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Na 23, Cl 35.5 density of water 1g cm3 2marks b Water containing hydrogen carbonate, HCO3-and calcium ions, Ca2 is said to be hard. Explain how these ions get into sources of water. 2marks www.freekcsepastpapers.comPage 103 c Analysis of river water sample showed the presence of the following ions: Mg2 , Na , Cl , 24SO i Name the type of water hardness present in the sample 1mark ii Identify two methods used to remove this type of hardness. 2marks d Study the information in the table below and answer the questions that follow. Salt Solubility in g 100g water At 400C At 600C Na NO3 38 24 Na Cl 101 52 A mixture containing 31g NaNO3 and 47g NaCl in 100g of water at 600c was cooled to 400c. A Which salt crystallizes out and by what mass 1mark b Identify the method used to obtain crystals 1mark 5. A The diagram below shows the Frasch process used for extraction of sulphur. Use it to answer the questions that follow. I Identify X 1mark ii Why is it necessary to use superheated water in this process? 1mark iii State two physical properties of sulphur that makes it possible for it to be extracted by this method 2marks b The diagram below shows part of the process in the manufacture of sulphuric VI acid. Study it and answer the questions that follow. I Write an equation for the reaction in the absorption chamber 1mark ii Explain how the acid is obtained after the reaction in the absorption chamber 1mark iii State two roles of the heat exchanger 2marks iv How is pollution controlled in the above process 1mark www.freekcsepastpapers.comPage 104 c Complete the table below to show the observation made and property when sulphur IV oxide is bubbled through the following. 3marks Substance Observation Property Acidified potassium Dichromate VI solution 1mark mark Moist hydrogen sulphide 1mark mark 6. |
Study it and answer the questions that follow. I Write an equation for the reaction in the absorption chamber 1mark ii Explain how the acid is obtained after the reaction in the absorption chamber 1mark iii State two roles of the heat exchanger 2marks iv How is pollution controlled in the above process 1mark www.freekcsepastpapers.comPage 104 c Complete the table below to show the observation made and property when sulphur IV oxide is bubbled through the following. 3marks Substance Observation Property Acidified potassium Dichromate VI solution 1mark mark Moist hydrogen sulphide 1mark mark 6. A Use the following data to calculate the enthalpy change for the decomposition of calcium carbonate Ca s O2 g Ca O s H -635kJmol-1 Ca s C s 3 2O2 g Ca CO3 s H - 1207kJ mol C s O2 g CO2 g H -394kJ Mol 2marks b State two factors to consider when choosing a fuel 1mark c The diagram below represents a set up used to determine the molar heat of combustion of ethanol. Calculate: i Heat given out during the experiment density of water 1g cm3, C 4.2kJ kg k 2marks ii Molar heat of combustion C 12, O 16, H 1 2marks iii Write the thermochemical equation for the combustion of ethanol 1mark d i State Hess s law 1mark ii Study the information below and answer the questions that follow. MgCl2 s Mg2 g 2 Cl- g H 2487kJ mol. |
A Use the following data to calculate the enthalpy change for the decomposition of calcium carbonate Ca s O2 g Ca O s H -635kJmol-1 Ca s C s 3 2O2 g Ca CO3 s H - 1207kJ mol C s O2 g CO2 g H -394kJ Mol 2marks b State two factors to consider when choosing a fuel 1mark c The diagram below represents a set up used to determine the molar heat of combustion of ethanol. Calculate: i Heat given out during the experiment density of water 1g cm3, C 4.2kJ kg k 2marks ii Molar heat of combustion C 12, O 16, H 1 2marks iii Write the thermochemical equation for the combustion of ethanol 1mark d i State Hess s law 1mark ii Study the information below and answer the questions that follow. MgCl2 s Mg2 g 2 Cl- g H 2487kJ mol. MgCl2 s aq Mg Cl2 aq H2 -170 kJ mol 2Cl- g aq 2Cl- aq H3 -762kJ mol a Name the enthalpies H1 and H2 1mark b Determine the enthalpy for the reaction 2marks Mg2 g aq Mg 2 aq 7. A Study the flow chart below and use it to answer the questions that follow. |
MgCl2 s Mg2 g 2 Cl- g H 2487kJ mol. MgCl2 s aq Mg Cl2 aq H2 -170 kJ mol 2Cl- g aq 2Cl- aq H3 -762kJ mol a Name the enthalpies H1 and H2 1mark b Determine the enthalpy for the reaction 2marks Mg2 g aq Mg 2 aq 7. A Study the flow chart below and use it to answer the questions that follow. Results: Initial water temperature 22.00C Final water temperature 44.50C Mass of lamp before burning 126.5g Mass of lamp after burning 125.0gwww.freekcsepastpapers.comPage 105 I Name: R, S and T 3marks II Write the chemical equation for the reaction between i R and concentrated sulphuric VI acid 1mark ii T and hydrochloric acid 1mark III What is the role played by R in the reaction in II i above 1mark b Study the flow chart below and use it to answer the questions that follow. |
MgCl2 s aq Mg Cl2 aq H2 -170 kJ mol 2Cl- g aq 2Cl- aq H3 -762kJ mol a Name the enthalpies H1 and H2 1mark b Determine the enthalpy for the reaction 2marks Mg2 g aq Mg 2 aq 7. A Study the flow chart below and use it to answer the questions that follow. Results: Initial water temperature 22.00C Final water temperature 44.50C Mass of lamp before burning 126.5g Mass of lamp after burning 125.0gwww.freekcsepastpapers.comPage 105 I Name: R, S and T 3marks II Write the chemical equation for the reaction between i R and concentrated sulphuric VI acid 1mark ii T and hydrochloric acid 1mark III What is the role played by R in the reaction in II i above 1mark b Study the flow chart below and use it to answer the questions that follow. I Write the formula of the metal ion in solution W 1mark ii Name the white precipitate Q 1 mark iii What property of the white precipitate is illustrated in step II and III 1mark iv Write the equation for the reaction taking place in step II 1mark www.freekcsepastpapers.comPage 106 CEKENAS PREMOCK EXAMINATION, 2023 Kenya Certificate of Secondary Education 233 3 CHEMISTRY PAPER 3 CONFIDENTIAL INSTRUCTIONS In addition to the laboratory facilities each student requires the following: About 50cm3 of solution P About 80cm3 of solution Q Two pieces of solid M A burette A pipette and pipette filler 50cm3 measuring cylinder Thermometer A stop watch A 250ml volumetric flask A 250ml empty beaker A 100ml plastic beaker One label 2 conical flasks Complete stand About 10cm3of liquid L in a stopped boiling tube. |
A Study the flow chart below and use it to answer the questions that follow. Results: Initial water temperature 22.00C Final water temperature 44.50C Mass of lamp before burning 126.5g Mass of lamp after burning 125.0gwww.freekcsepastpapers.comPage 105 I Name: R, S and T 3marks II Write the chemical equation for the reaction between i R and concentrated sulphuric VI acid 1mark ii T and hydrochloric acid 1mark III What is the role played by R in the reaction in II i above 1mark b Study the flow chart below and use it to answer the questions that follow. I Write the formula of the metal ion in solution W 1mark ii Name the white precipitate Q 1 mark iii What property of the white precipitate is illustrated in step II and III 1mark iv Write the equation for the reaction taking place in step II 1mark www.freekcsepastpapers.comPage 106 CEKENAS PREMOCK EXAMINATION, 2023 Kenya Certificate of Secondary Education 233 3 CHEMISTRY PAPER 3 CONFIDENTIAL INSTRUCTIONS In addition to the laboratory facilities each student requires the following: About 50cm3 of solution P About 80cm3 of solution Q Two pieces of solid M A burette A pipette and pipette filler 50cm3 measuring cylinder Thermometer A stop watch A 250ml volumetric flask A 250ml empty beaker A 100ml plastic beaker One label 2 conical flasks Complete stand About 10cm3of liquid L in a stopped boiling tube. Six test tubes and a test tubes rack About 10cm3of solutions R in boiling tube Wooden splint Spatula Filter paper and filter funnel Access to Source of heat. |
B ALL working MUST be clearly shown where necessary. C Mathematical table and silent electronic calculators may be used. 1. You are provided with: i Solution P which is a monobasic acid solution. Ii 2cm long magnesium ribbon labelled metal M. iii 0.5M sodium hydroxide solution Q You are required to: a Calculate the mass of the 2cm long metal M. b Determine the molarity of the dibasic acid solution P. PROCEDURE 1 Measure exactly 40cm3 of solution P using 50ml measuring cylinder and transfer it into a 100ml plastic beaker. Measure the temperature of the solution after every thirty seconds for the first sixty and record in table I below. At exactly 90 seconds add the 2cm long solid M and record the temperature of the solution after every thirty seconds up to 300 seconds RETAIN THIS SOLUTION FOR PROCEDURE II BELOW Table I Time sec 0 30 60 90 120 150 180 210 240 270 300 Temperature X 4marks a Draw a graph of temperature against time in the grid provided below. 3marks b From the graph determine the highest temperature change, T 1mark c Calculate the heat change for the reaction above in kJ 1mark Density of solution 1g cm3 specific Heat capacity of solution 4.2Jg-K-mol- d i Given that the molar enthalpy reaction between metal M and acid P is 1590kJmol , determine the number of moles of metals M in the 2cm long pieces. 1mark e Given that R.A.M of Magnesium is 24.1. Calculate the mass of the 2cm long ribbon 1mark PROCEDURE II Transfer all the solution formed from procedure I into a 250ml volumetric flask. Add distilled water to the mark, transfer the solution into a 250ml beaker and this solution as P1. Fill the burette with solution Q Pipette 25cm 3 of solutions P1 into a 250 ml conical flask. Titrate solution Q against P1 using phenolphthalein indicator and record your results in table II below. Repeat the titration two more times to get consider values. |
The diagram below shows part of the Frasch process used for extraction of sulphur. Use it to answer the questions that follow. A Identify X 1mk b Why is it necessary to use superheated water and hot compressed air in this process? 1mk c State two physical properties of sulphur that makes it possible for it to be extracted by this method. 1mk 10. Hydrogen sulphide gas was bubbled through a solution of zinc nitrate for some time. I. State observation made. 1mk ii. Where should the experiment be carried out and why? 1mk iii. Write the equation of the reaction that occurs. 1mk 11. Calcium carbonate reacts with dilute sulphuric VI acid to form a gas and a salt. I. Write an equation for the above reaction. 1mk ii. Why would the above reactants not be suitable for preparation of the above gas in the laboratory? 2mks 12. A student prepared ammonia gas and bubbled it in a solution of copper II sulphite as shown below. A State the observation made in the beaker after; i. A short while 1 mk ii. A long while 1 mk b Write the formula of the ion formed in the beaker in a ii above. X Heat Mixture of NH4Cl and Ca OH 2 Beaker Copper II sulphate solution 15atm www.freekcsepastpapers.comPage 119 13. Study the table below and answer the question that follow. Solution pH A 3.0 B 14.0 C 8.0 i. In which solution will phenolphthalein indicator be colourless? Explain 1mk ii. Which of the solutions can be used to relieve a heartburn. Explain 1mk iii. Which two solutions can react with zinc oxide. 1 mk 14. The diagram below shows a set up that was used to show the part of air used in burning. A Given that phosphorous was in excess, draw a diagram of the set up at the end of the experiment when there was no further observable change. 1 mk b Suggest of one modification that can be made to the apparatus if the percentage of air used is to be determined. |
How will increase in pressure affect the yield of nitrogen II oxide? 1mk 20. After 7.5 hrs the percentage of a certain nuclide in a sample of ore was found to be 12.5 . A What is meant by the term half-life? 1mk b Determine the half-life of the nuclide. 2mks 21. Name the following compound. Ii. CH3 COOCH2CH2CH3 1 mk b Complete the equation below. 1mk Inverted gas jar A piece of burning phosphorous Waterwww.freekcsepastpapers.comPage 120 22. The diagram below represented a set up that was used to react Lithium with water. Study it and answer the question that follow. A Complete the diagram to show how the gas formed can be collected. 1mk b Write an equation for the reaction that takes place. 1mk c Why would it not be advisable to use potassium in place of lithium in the above set up. 1mk 23. During extraction of aluminium. Aluminium oxide with melting point of 20540C is electrolysed but the temperature is maintained between 8000C and 9000C. a Explain why electrolysis is not carried at 20540C 1mk b How can the temperature be lowered from 20540C to about 8000C 1mk c State one use of aluminium. 1 mk 24. The scheme below represents reactions starting with solid X. i. Identify solid X. 1mk ii. Write an ionic equation to show formation of white precipitate. 1 mk iii. Why would gas S not form a white precipitate with solution of sodium hydroxide. 25. The electrode potentials for elements C and D are given below. C 2 aq 2 e- C s E - 0.38V D 2 aq 2 e- D s E -0.67V Is it advisable to store a nitrate solution of C in a container made of element D? Explain showing your working. 3 mks 26. A Water is polar. What is meant by the term polar? |
Name the catalyst Y. 1mk II. State one commercial use of sulphuric VI acid. 1mk d i. The copper obtained from the chamber N is not pure. Draw a labelled diagram to show the set up you would use to refine the copper by electrolysis. 2mks ii. Given that the mass of copper obtained from the above extraction was 210kg. Determine the percentage purity of the ore copper pyrites if 810kg of it was fed to the 1st roasting furnace. Cu 63.5, Fe 56, D 32 3mks 4. Use the standard electrode potentials given below to answer the questions that follow. A Select two half cells which when connected give the lowest electromotive force e.m.f 1mk b Calculate the e.m.f of the cell formed by combining the half cells in a above. 1mk c Select the; i. Strongest oxidizing agent. 1 2 mk ii. Strongest reducing agent 1 2 mk d A cell was set up using lead and zinc electrodes as shown below. I. Write the half cell equation for the half cell in which oxidation takes place. 1 mk ii. Write the overall cell equation. 1mk iii. What is the role of the salt bridge? 2mks e An iron knife was electroplated using chromium. The knife was thoroughly cleaned and weighed before being dipped in the electrolyte used. I. Why is it necessary to clean the knife before electrolysis is carried out. 1mk ii. A current of 0.75A was passed through the electrolyte for one hour and 4 minutes. The mass of chromium deposited on the knife was 0.52g. Determine the valency of chromium. 1F 96500C, Cr 52 2mks 5. The sketch below represents a graph obtained when zinc granules were reacted with excess 0.2M sulphuric acid in the presence of a catalyst in a conical flask placed on an electronic balance. Www.freekcsepastpapers.comPage 124 a i Write an equation for the reaction that took place. 1mk ii. Explain why there is loss in mass. |
Www.freekcsepastpapers.comPage 124 a i Write an equation for the reaction that took place. 1mk ii. Explain why there is loss in mass. 1mk b Sketch on the same axes, the curve obtained when: I: Same mass of zinc powder was used under the same conditions. Label it P. 1mk II: No catalyst was used. Label it N. 1 mk c In the contact process, sulphur IV oxide is converted to sulphur VI oxide in the catalytic chamber in which a dynamic equilibrium is reached. 2 SO2 aq O 2 g 2SO 2 g H -97kJ Mol i. What is meant by dynamic equilibrium? 2mks ii. State and explain how each of the following would affect the position of the equilibrium. I. Decrease in pressure. 2mks II. Decrease in temperature. 2mks d An equilibrium exists between chromate and dichromate ions as shown below. 2CrO4 2- aq 2H Cr2O7 2- aq H2O l yellow aq Orange State and explain the observation made when aqueous sodium hydroxide is added to the above mixture. 2mks 6. A The table below shows properties of chlorine, bromine and iodine. Complete the table by giving the missing information in i , ii and iii 3mks b Chlorine gas is prepared by reacting concentrated hydrochloric acid with manganese IV oxide. I. Write the equation for reaction between concentrated hydrochloric acid and manganese IV oxide. 1mk ii. What is the role of manganese IV oxide in this reaction. 1mk c i. Iron II chloride reacts with chlorine gas to form substance E. Identify substance E. 1mk ii. During the reaction in c i above, 6.30g of iron II chloride were converted to substance E. Calculate the volume of chlorine used. |
1mk ii. During the reaction in c i above, 6.30g of iron II chloride were converted to substance E. Calculate the volume of chlorine used. 3mks Cl 35.5, Molar gas volume at room temperature 24000cm3, Fe 56 d Draw and name the structure of the compound formed when excess chlorine gas is reacted with ethane gas. 2mks e Give two industrial uses of chlorine. 2mks 7. In an experiment 50cm3 of 1.0M sodium hydroxide solution was placed in a suitable apparatus and 5.0cm3 portion of hydroxide acid were added. The resulting mixture was stirred with a thermometer and temperature recorded after each addition. Volume of HCl cm3 5 10 15 20 25 30 35 40 45 50 Temperature 0C 21.5 22.5 24.0 25.0 26.0 27.0 27.5 27.5 27.0 26.5 a Plot a graph of temperature against volume of the acid added. 3mks b i. From the graph determine volume of HCl used to neutralize 50cm3 of 1M NaOH. 1mk ii. Hence determine concentration of the HCl in moles per litre. 3mks c i. Calculate the amount of heat produced in the reaction Specific heat capacity 4.2 kjKg-1 k-1 and density of the solution 1g cm3 2 mks ii. Hence calculate the molar enthalpy of neutralization of sodium hydroxide. 1mk www.freekcsepastpapers.comPage 125 KIRINYAGA CENTRAL EFFECTIVE 40 JOINT EXAMINATION, 2023 233 3 CHEMISTRY PAPER 3 CONFIDENTIAL Each candidate should have the following :- 1. 90cm3 of solution X. 2. 100cm3 of solution Y. 3. 120cm3 of solution Z. 4. 6 test tubes in a rack and 1 boiling tube. 5. 50ml measuring cylinder. 6. A conical flask. 7. A burette. 8. A 25ml pipette. 9. |
8. A 25ml pipette. 9. A thermometer -100C 1100C 10. Stopwatch. 11. About 15cm3 of liquid Q. 12. Watch glass. 13. Test tube holder. 14. 0.1g NaHCO3. 15. A dropper. 16. 1g ammonium iron II sulphate hexahydrate. Labelled solid T NH4 2 SO4FeSO4.6H2O 17. 500cm3 distilled water in a wash bottle. 18. Metallic spatula. 19. One blue litmus paper and one red litmus paper. Access to:- 1. 2M NaOH with own dropper. 2. 0.1M acidified potassium dichromate VI with a dropper. 3. 0.2Macidified barium nitrate with own dropper. 4. 20 hydrogen peroxide with own dropper. 5. 2M NH4OH with own dropper. 6. 0.02M acidified potassium manganate VII with a dropper. 7. Bunsen burner flame. Solution preparation confidential. 1. Solution X- Ferrous Ammonium sulphate. Prepared by dissolving 34g of Ferrous Ammonium Sulphate in 1000cm3 of distilled water. Note that this solution should be prepared the morning of the exam and also per shift to prevent oxidation. 2. Solution Y Acidified potassium manganate VII . Prepared by dissolving 3g of potassium Manganate vii crystals in 800cm3 of distilled water then adding 200cm3 of 2M sulphuric VI acid. 3. Solution Z Oxalic acid. Prepared by dissolving 6.3g of oxalic acid in 1000cm3 of water. 4. Acidified potassium dichromate VI is prepared by dissolving 29.4g in 200cm3 2M sulphuric VI acid and top up to 1litre using distilled water. 5. Acidified barium nitrate is prepared by dissolving 52.3g of barium nitrate in 200cm3 of HNO3 and top up the solution with distilled water to 1l 1000cm3 6. Liquid Q is ethanol. |
1 mk b Given that the equation for the reaction between solution Y and X is: MnO- 4 aq 8H aq 5Fe 2 aq Mn2 aq 5Fe3 aq 4H2O l Determine i. The number of moles of iron II salt, solution X in 25cm3 of the solution used. 1 mk ii. The concentration of solution X in moles per litre. 1 mk iii. The relative formula mass of the iron II salt. 1mk iv. The value of n in the formula FeSO4 NH4 2SO4.nH2O. 1mk Fe 56, N 14, S 32, O 16, H 1 Procedure 2 Using a burette place 1 cm3 of solution Y in each of the 5 test tubes on the rack. Measure 20cm3 of solution Z into a boiling tube using a measuring cylinder. Put a thermometer into solution Z in the boiling tube and warm it until it attains a temperature of 400C. Place the boiling tube in the rack and add the first portion of solution Y in the test tube and immediately start the start watch. Record the time taken for the purple colour to be decolourised in the table 2 below. Repeat the procedure above with 20cm3 solution Z at 500C, 600C, 700C and 800C to fill table 2. Clean the test tubes and the burette immediately you finish the experiment. Table 2 4 mks Temperature of solution Z 0C 40 50 60 70 80 Time taken for colour to decolourise sec t Rate 1 t sec-1 a On the grid below, plot a graph of rate l t against temperature 0C . 3mks b From the graph, determine the time for decolourisation of the mixture if temperature of solution was 580C. 1mk c Explain how the rate of reaction between solution Y and solution Z varies with change in temperature. 2mks www.freekcsepastpapers.comPage 127 2. You are provided with organic liquid Q. |
Give one reason why they have low melting points. 1 mark 3. A heavy metal P was dissolved in dilute nitric acid to form a solution of compound P NO3 2. Portions of the resulting solution were treated as follows: i To the first portion a solution of dilute hydrochloric acid is added, where a white precipitate S is formed, which dissolves on warming. Ii The second portion is treated with two drops of 2M Sodium hydroxide solution where a white precipitate T is formed. The white precipitate dissolved in excess sodium hydroxide to form a colourless solution. Iii A solution of potassium iodide is added to the third portion where a yellow precipitate U is formed. Iv When the resulting solution is evaporated to dryness and heated strongly a yellow solid V is formed and a brown gas W and a colourless gas X are formed. A. Identify the substances P, S, T, U, V, W 3 marks b. Write an ionic equation of the reaction that occurs in part iii 1 mark A B C Fwww.freekcsepastpapers.comPage 137 4. 100cm3 of air is continuously passed through a combustion tube connected to two syringes as shown below. The combustion tube contains some clean granules of copper metal which are heated. The process is repeated until there is no further change in the volume of air. The volume of air remaining is 80cm3 i State one observation made in the combustion tube 1mark ii Work out the percentage of air used after the reaction 1mark iii List two gases remaining after the reaction 1 mark iv Would the reaction take place if it is repeated with magnesium in place of copper metal explain 1mk 5. The electronic configuration of the ions of X3 and Y are 2, 8 and 2, 8 respectively. I . Write the electronic configuration of the neutral atoms of X and Y 1 mark ii . Write the formula of the compound formed between element X and O 1 mark iii . Compare the atomic radius of element X and Y 2 marks 6. The diagram below represents an experiment which was carried out by a student, to investigate the effect of passing an electric current on molten sodium chloride. I . Molten sodium chloride is a binary electrolyte. |
The diagram below represents an experiment which was carried out by a student, to investigate the effect of passing an electric current on molten sodium chloride. I . Molten sodium chloride is a binary electrolyte. State the meaning of the term binary electrolyte. 1 mark ii . State two observations made at the anode 1 mark iii . Write an equation to show what happens at the cathode. 1 mark iv Show the direction of flow of electrons on the set up mark 7. 100cm3 of propane gas diffuses through a porous plug in 20 seconds. How long would it take for 80cm3 of methane gas to diffuse through the same plug? C 12, H 1 3marks Combustion tubeSyringe AHeated Copper MetalSyringe BGraphite electrodeBeakerMolten Sodium Chloridewww.freekcsepastpapers.comPage 138 8. The graphs below were drawn when 15g of marble chips in different physical states were reacted with 50cm3 of 2M Hydrochloric acid. They are drawn by measuring the volume of carbon iv oxide produced with time. A Which curves corresponds to the reactions involving powdered calcium carbonate and large sized marble chips with the dilute acid. I Powdered calcium carbonate 1 mark ii Large sized calcium carbonate 1 mark b All the graphs eventually flatten out at the same level but at different time. Why do the graphs flatten out at the same level? 1 mark c Why is curve A very steep at any given point compared to the other curves 1 mark 9. One mole of ethane gas was mixed with excess chlorine gas in a gas jar at room temperature and kept in dark conditions. On observation, no reaction occurred in the dark conditions. On exposure to light the chlorine gas was decolourised. A State the importance of light in the above reaction. 1 mark b Write an equation for the reaction that occurs once the mixture is exposed to light.1mark c Name the organic product formed in the above reaction 1mark 10. Below is an equation showing an equilibrium Br2 aq H2O l Br aq 2H aq OBr aq State and explain the observation that would be made if some drops of concentrated sodium hydroxide solution were introduced to the equilibrium mixture 3 marks 11. |
A State the importance of light in the above reaction. 1 mark b Write an equation for the reaction that occurs once the mixture is exposed to light.1mark c Name the organic product formed in the above reaction 1mark 10. Below is an equation showing an equilibrium Br2 aq H2O l Br aq 2H aq OBr aq State and explain the observation that would be made if some drops of concentrated sodium hydroxide solution were introduced to the equilibrium mixture 3 marks 11. A mixture of dilute nitric acid 50 water 50 acid was reacted with copper turnings in a round bottomed flask. I Name the gas that is produced in the above case. 1 mark ii Write a balanced equation to show the reaction 1 mark iii State two physical properties of the gas evolved above. 1 mark 12. The molar enthalpy of combustion of propanol is 1560Kjmol 1 i Write an equation to show the combustion of ethanol completely in oxygen 1 mark ii Calculate the amount of energy in joules released when10g of propanol is burnt in excess oxygen 2 marks iii The practically obtained value of enthalpy of combustion of propanol is less than the value obtained from books. Give two reasons for the above variation. 1 mark 13. Given a solid sample of calcium carbonate and sodium chloride, explain how you can obtain some pure crystals of sodium chloride. 3 marks Volume of Co 4050Curve ACurve BCurve CTime4050www.freekcsepastpapers.comPage 139 14 The solubility curves below shows the solubility of two salts A and B in water. Study it and answer the questions that follow: i Which salt is more soluble in water at 70oc 1mark ii Work out the amount of salt that would saturate 50gm of water at 120sc 2mark 15. 3.78g of a hydrated salt of iron II sulphate, FeSO4, in H2O were heated until all the water of crystallization was driven off. The anhydrous salt left had a mass of 1.52g. Determine the formula of the hydrated salt. |
3.78g of a hydrated salt of iron II sulphate, FeSO4, in H2O were heated until all the water of crystallization was driven off. The anhydrous salt left had a mass of 1.52g. Determine the formula of the hydrated salt. Fe 56, S 32, H 1, O 16 3 marks 16. A steady current of 0.2 Amperes was passed through molten silver bromide for 80 minutes. I . Calculate the quantity of electricity that passed through the set up. 1 mark ii . Calculate the mass of product deposited at the cathode. 1F 96500C; Ag 108, Br 80 2 marks 17. The apparatus set up below was used to prepare an anhydrous solid P i Identify solid P 1 mark ii Write an equation for formation of solid P 1 mark iii Suppose the gas used in the set up was dry hydrogen chloride gas; what would be the product obtained after the reaction? Give a reason for your answer 1020 40 60 80 100 120 140Salt ASalt BSolubility g per 100g of H o2Temp C 0DryChlorine gasDrying agent MIron wireSolid Pwww.freekcsepastpapers.comPage 140 18. A radioactive cobalt Co6128 undergoes decay by emitting a beta particle and forming Nickel atom, a Write a balanced decay equation for the above change 1 mark b If a sample of the cobalt has an activity of 1000 counts per minute, determine the time it would take for its activity to decrease to 62.50 if the half-life of the element is 30years 2 marks c Define the term half-life. 1 mark 19. |
Give a reason for your answer 1020 40 60 80 100 120 140Salt ASalt BSolubility g per 100g of H o2Temp C 0DryChlorine gasDrying agent MIron wireSolid Pwww.freekcsepastpapers.comPage 140 18. A radioactive cobalt Co6128 undergoes decay by emitting a beta particle and forming Nickel atom, a Write a balanced decay equation for the above change 1 mark b If a sample of the cobalt has an activity of 1000 counts per minute, determine the time it would take for its activity to decrease to 62.50 if the half-life of the element is 30years 2 marks c Define the term half-life. 1 mark 19. The table below gives the solubility of potassium bromide and potassium sulphate at 0oc and 40oC Substance Solubility g 100g H2O at 0oc 40oC Potassium bromide 55 75 Potassium sulphate 10 12 When an aqueous mixture containing 60g of potassium bromide and 7g potassium sulphate in 100g of water at 80oc was cooled to 0oC, some crystals were formed a Identify the crystals 1mark b Determine the mass of the crystals 1mark c Name the method used to obtain the crystals 1mark 20. The table below gives some information about the melting and the likely structures in substances V, W, and X. Complete the table by filling the missing Information in the spaces numbered. I, II and III 3marks Element Structure Example Melting point V Grant Metallic i High W ii F2 Low X iii Si Very high 21. Use for diagram below to answer the questions that follows:- a Name the letter that corresponds to: i Activation energy of the reaction 1mark ii Change in energy for the overall reaction. 1mark b The reaction exothermic or endothermic. Explain. 2mark www.freekcsepastpapers.comPage 141 22. Study the set up below and answer the question that follows a Write an equation for the reaction which takes place in the combustion tube. |
Explain. 2mark www.freekcsepastpapers.comPage 141 22. Study the set up below and answer the question that follows a Write an equation for the reaction which takes place in the combustion tube. 1mark b What property of gas Z to allows it to be collected as shown in the diagram . 1mark c Identify gas Z 1mark 23. The setup below was used to prepare dry sample or hydrogen sulphide gas. A Complete the diagram to show how the gas was collected. 1mark b Identify the following solids; H J 2marks 24. The table below shows the atomic and ionic radius of some elements. Element Atomic Radius nm Ionic radius nm U V W X 0.174 0.203 0.099 0.136 0.099 0.133 0.181 0.065 a Classify X as a metal or non-metal. Explain 1mark b Identify the element which is the strongest reducing agent. 1mark c Which element forms an anion? 1mark www.freekcsepastpapers.comPage 142 WEITHAGA JOINT MOCK EXAMINATIONS, 2023 Kenya Certificate of Secondary Education 233 2 Chemistry PAPER 2 Theory TIME: 2 HOURS 1. I The table below shows properties of some elements represented by symbols W, X, Y and Z. Study the information in the table and answer the questions that follows Element No. Of protons Atomic radius nm Boiling point 0C W 2 0.93 -269 X 10 1.31 -246 Y 18 1.54 -186 Z 36 1.89 -152 a Write down the electron arrangement for elements W and X 1mk b In which group of the periodic table are the elements in the table above? Give the name of the group 2mks c Explain why the atomic radius of W is smaller than that of X 1mk d state one use of element X 1mk II. The section below represents part of the periodic table. Study it and answer the questions that follow. The letters are not the actual symbol of the elements. Q X B H M T Y A V Z S a Select the least reactive non-metal. |
Study it and answer the questions that follow. The letters are not the actual symbol of the elements. Q X B H M T Y A V Z S a Select the least reactive non-metal. 1mk b Which of the elements has the greatest tendency of forming covalent compounds in nature? Explain your choice. 1mk c Explain why the atomic radius of T is smaller than that of M. 2mks d Compare the electrical conductivity of element X and B. 2mks 2. Two half cells were connected as shown to form a voltaic cell. The reduction potentials are given. Pb2 aq 2e Pb s E 0.13V Fe2 aq 2e Fe s E 0.44V a Calculate the e.m.f of the cell. 1mk b Sodium chloride is used as the salt bridge. State the two functions of the salt bridge. 2mks c Show the direction of the electron flow in the external circuit. 1mk d The e.m.f of the cell will reduce with time. Give a reason for this. 1mk www.freekcsepastpapers.comPage 143 e During electrolysis of water acidified with Sulphuric acid, two gases were produced at the electrodes: i State which ions are preferentially discharged at the electrodes. Explain with aid of half ionic equations. Anode. 1mk Cathode. 1mks ii Calculate the volume of the gases at s.t.p produced when a current of 0.025A is passed for 4 hours. 1 Faraday 96500C 3mks 3. A The fermentation of glucose is catalysed by enzymes from yeast. Yeast is added to aqueous glucose, the solution starts to bubble and becomes cloudy as more yeast cells are formed. C6H12O6 aq 2C2H5OH aq 2CO2 g The reaction is exothermic. Eventually the fermentation stops when the concentration of ethanol is about 12 . I On a large scale, the reaction mixture is cooled. Suggest a reason why this is necessary. 1mk ii Why does the fermentation stop? Suggest one reasons. |
An experiment was carried out using magnesium ribbon and dilute hydrochloric acid of different concentrations. The time needed to produce 50cm3 of the gas for every experiment was recorded in a table. Concentration of HCl moles per litre 2.0 1.75 1.50 1.25 1.00 0.75 0.50 0.25 Time seconds 8.8 10.0 11.7 14.0 17.5 18.7 35.0 70.0 time1 Sec-1 a Complete the table above for 1 time. 4mks b Plot a graph of rate i.e 1 time against concentration. 3mks www.freekcsepastpapers.comPage 144 c From your graph determine the concentration needed to produce 50cm3 of hydrogen gas when time is 15.0 seconds 1mk d From your graph state the relationship between the rate of reaction and concentration. Give a reason. 1mk e A state of equilibrium between dichromate vi and chromate ions is established as shown below Cr2O72- aq 2OH- aq 2CrO42- aq H2O l Orange Yellow i What is meant by dynamic equilibrium? 1mk ii State and explain observation made, when a few drops of Hydrochloric acid are added to equilibrium mixture 2mks 5. A Read the following passage and answer the questions. A salt K was heated with slaked lime calcium hydroxide . A colourless gas L with a characteristic smell and turns red litmus paper blue was evolved. A large quantity of this gas was passed through an inverted filter funnel into Copper II sulphate solution, and a deep blue solution M was obtained. I Identify gas L 1mk ii What is K most likely to be? 1mk iii Write an equation for the reaction between K and slaked lime 1mk iv . |
1mk ii What is the identity of metal F. 1mk iii State the name of the ore from which metal F is extracted. 1mk iv Explain why the metal loses its lustre when exposed to air. 1mk v What is the function of wire gauze shell that separates the anode from the cathode? 1mk vi Write a chemical equation for the reaction between metal F and ammonia 1mk vii Apart from being a deoxidizing agent, state two other uses of metal F. 1mks b During extraction of aluminium by electrolysis, molten cryolite is used instead of water and the anode must be replaced from time to time. I State the main ore from which aluminium is extracted 1mk ii Explain why cryolite is preferred over water 1mk iii Give a reason why the anode is replaced from time to time. 1mk iv Extraction of aluminium is very expensive compared to other metals like Iron, explain 1mk 8. A Consider the following reaction: A2 g B2 g 2AB g , H 75 kJ Sketch an energy level diagram showing the relative activation energies for the catalysed and uncatalysed reactions using the axes below. 2mks b The following data was obtained during an experiment Mass of ethanol burnt 0.2g Mass of water in the calorimeter 200g Specific heat capacity of water 4.2 jg-1k-1 Initial temperature of water 23.5 0C Final temperature of water 28.0 0C i How was the mass of ethanol that burnt determined? 1mk ii How much heat was required to raise the temperature of water from 23.5 0C to 28.00C? 2mks iii Two assumptions were made in calculating the enthalpy of combustion for ethanol. State them. 1mk iv Determine the molar enthalpy of combustion of ethanol. C 12,H 1,O 16 2mks v Write a thermochemical equation for the combustion of ethanol given the accurate value for enthalpy of combustion is 1368 kJmol-1. |
11. 400cm2 of distilled water. 12. Means of labeling. 13. About 0.5g of NaHCO3 Solid A. 14. 5cm3 of solution D. 15. About 1g of solid R. 16. Bunsen burner. Access to: 2M aqueous ammonia solution supplied with a dropper. Phenolphthalein indicator supplied with a dropper. 0.5M KI solution. 2M HCL 2M NaOH Zinc granules. 0.5 g Acidified KMnO4 supplied with a dropper. Acidified K2Cr2O7 supplied with a dropper. Solution D is a mixture of Pb NO3 2 and Cu NO3 2 ratio 1:1 Solid R is a maleic acid. Www.freekcsepastpapers.comPage 164 MURANG A EXTRA COUNTY SCHOOLS EXAMINATION. Kenya Certificate of Secondary Education 233 1 Chemistry Paper 1 Theory TIME: 2 HOURS 1 a Bauxite is the chief ore found in the extraction of Aluminium. Name two impurities found in bauxite 2mks b Name the chief ores of both zinc and copper 1mk i zinc ii copper 2. A Identify the products formed when dinitrogen tetra oxide is dissolved in water 2mks b Write the balanced equation for the reaction above 1mk 3. State one use of the following substances 3mks i AgBr ii CaSO4.XH2O iii Tincture of iodine 4. The grid below represents part of the periodic table. Study it and answer the questions that follow .The letters given do not represent the actual symbols of the elements. A B C D E F G H i Select the element that can form a divalent anion mk . Ii Name type of structure would the oxide of C have? Mk . Iii How does the melting point of A compare with that of E? Mk . |
Mk . Iii How does the melting point of A compare with that of E? Mk . Iv 2.6 g of B reacts completely when heated with 2.42 litres of chlorine gas Cl2 at s.t.p, calculate the relative atomic mass of B. 1 mole of gas occupies 22.4 litres at s.t.p. 112mk . 5. Explain the differences in bleaching properties of chlorine and sulphur use equations where necessary 3mks 6. Metals K and N were connected to form a cell as shown in the diagram below. Their reduction potentials are as shown below: K aq K s - 0.17V N aq N s 1.1 6Vwww.freekcsepastpapers.comPage 165 i P is made by dipping a filter paper in a solution of sodium nitrate, on the salt bridge show the direction of flow of ions 1mk ii On the diagram, show the flow of electrons 1mk iii Write the equation for the half-cell reaction that occurs at 1mk Metal K electrode........................................................................... Metal N electrode........................................................................... 7. Write equations for the reactions between the following metals and steam. 3mks Iron Zinc Copper 8. Study the diagram below and answer the questions that follow. A. Name 1mk i Solid V ....... ii Gas W b. Describe a chemical test for chloride ions 2mks 9. Starting with ethanol, describe how a sample of tetrachloroethane can be prepared 3mks 10. A solution of bromine in water is a chemical reaction in equilibrium. The reaction involved is represented by the equation below; Br2 aq H2O l 2H aq Br- aq OBr- aq Yellow Colourless i State and explain the observation made when dilute sulphuric VI acid is added to the mixture at equilibrium. 2mks ii Define the term dynamic equilibrium 1mk 11. |
A solution of bromine in water is a chemical reaction in equilibrium. The reaction involved is represented by the equation below; Br2 aq H2O l 2H aq Br- aq OBr- aq Yellow Colourless i State and explain the observation made when dilute sulphuric VI acid is added to the mixture at equilibrium. 2mks ii Define the term dynamic equilibrium 1mk 11. Apart from downward delivery name another method that can be used to collect the following gases 2mks i Nitrogen IV oxide Sulphur VI oxide ii Name one gas that can be dried using anhydrous calcium oxide 1mk 12. Starting with magnesium metal describe how a sample of magnesium carbonate can be prepared. 3mks 13. With aid of well labelled diagrams show how a sample of sodium chloride, iodine and sand can be separated 3mks 14. Explain the following 3mks i Why number of protons and electrons are equal in an atom ii The role of neutrons in the nucleus of an atom iii Cations are positively charged 15. A In an experiment 10.6g of a mixture of a anhydrous Sodium Carbonate and Sodium chloride were dissolved in water to make 100cm3 of solution .25cm3of this solution required 20cm3 of 1M Hydrochloric acid solution for complete neutralization. I Calculate the number of moles of Hydrochloric acid used 1mk ii Write a balanced equation for the above reaction. 1mk iii Calculate the mass of Sodium Carbonate in 25 cm3 of this mixture. 1mk 16. Briefly describe how caffeine can be extracted from tea leaves. 3mks 17. State the two roles of platinized-platinum in a standard hydrogen electrode 2mks 18. |
Briefly describe how caffeine can be extracted from tea leaves. 3mks 17. State the two roles of platinized-platinum in a standard hydrogen electrode 2mks 18. Explain the following 3mks i Yellow phosphorus is stored under water ii Sodium is stored under paraffin oil iii Lime water and not potassium hydroxide is used to test for carbon iv oxide Solution of a sodium salt Solid V Gas W which turns K2Cr2O7 paper from orange to green BaCl2 aq HCl aq www.freekcsepastpapers.comPage 166 18. Study the information below and use it to answer the questions that follow H lattice MgCl2 - 2477kjmol-1 H hydration Cl-1 aq -363kjmol-1 H hydration Mg 2 aq -1891jmol-1 i Differentiate between hydration energy and lattice energy? 1mks ii Calculate the heat of solution of Magnesium Chloride 2mks 19. Nylon 6,6 is formed from two monomers, hexan-1,6-dioic acid adipic acid and hexan-1,6-diamine hexamethylene diamine through condensation polymerisation as shown in the diagrams below. A. Define condensation polymerisation 1mk b. Write the equation for the formation of Nylon 6,6 2mks 20. According to Bronsted-Lowry theory, define an acid 1mk NH3 aq H2O l NH4 aq OH- aq Identify the species that acts as; i A base. Explain . 1mks ii An acid. . Explain .. 1mk 21. A Explain how painting prevents iron from rusting 1mk b. Apart from protection from rusting state another reason for electroplating 1mk c. What is sacrificial protection, use an example to explain your answer. 2mks 22. The structure of RCOO-Na below represents a type of cleansing agent. Describe how the cleansing agent removes grease from a piece of cloth. 3mks 23. |
The structure of RCOO-Na below represents a type of cleansing agent. Describe how the cleansing agent removes grease from a piece of cloth. 3mks 23. The diagram below represents a jiko when in use. Study it and answer the questions that follow. I Write equations for the reactions that occur in region I: B 1 mk II: C 1 mk ii Explain what happens in region A. 1 mks 24. A compound contains 82.75 carbon and the rest is Hydrogen. C 12, H 1 a Determine its empirical formula. 2 Mrks b Determine the molecular formula if its molecular mass is 58. 1 Mks 25. Determine the oxidation state of manganese in the following; 3mks KMnO4 Mn2O3 26. Explain why the melting point of magnesium oxide is 3080 C while that of carbon IV oxide is -79oC. 2mks Region A Region B Region C Air inwww.freekcsepastpapers.comPage 167 MURANG A EXTRA COUNTY SCHOOLS EXAMINATION. Kenya Certificate of Secondary Education 233 2 Chemistry PAPER 2 Theory TIME: 2 HOURS 1. A The graph below represents the trend in melting points of elements in period 3. Study it and use it to answer the questions that follow i Explain the trend in melting point between Aluminum and Phosphorous. 2 marks ii Give a reason why Argon has the lowest melting point 1 mark b The table below shows the properties of several elements. Study it and use it to answer the questions that follow. Element Atomic radius nm Ionic radius nm P 0.136 0.065 Q 0.174 0.099 R 0.099 0.181 S 0.203 0.133 i Giving a reason, identify the nonmetal 2 marks ii Given that, element P and S belong to the same period of the periodic table, identify the element with a lower ionization energy. Explain. 2 marks c An element X forms an ion with the formula X2 . The electronic configuration of the ion is 2.8 i State the group and period to which element X belongs. |
Explain. 2 marks c An element X forms an ion with the formula X2 . The electronic configuration of the ion is 2.8 i State the group and period to which element X belongs. 1mark Group .. . Period ii Draw dot and cross diagram showing bonding when X combines with chlorine 1 mark d Explain the following observations; i Carbon has more than one melting point 1 mark ii Silicon and phosphorous are in the same period but at room temperature, the oxide of silicon is a solid, while the oxide of sulphur is gaseous 1 mark 2. A Determine the oxidation state of the element indicated in brackets 3 marks i. MnO4 Mn ii. K2 Cr2 O7 Cr iii. H3PO4 P www.freekcsepastpapers.comPage 168 b Below is a list of standard reduction potentials of some elements. Use it to answer the questions that follow. A 2 aq 2e A s 0.34 V N 2 aq 2e N s 0.76 V G aq 2e G s 0.00 V Y 2 aq 2e Y s 0.88 V L 2 aq 2e L s 2.16 V i Identify the strongest reducing agent 1 mark ii Explain why a solution containing A2 ions cannot be stored in a container made of metal N 1 mark iii The half cells of Y and L were combined to form an electrochemical cell. I Draw a well labelled diagram of the cell formed 3 marks II Calculate the e.m.f of the cell formed above 1 mark c The diagram below shows the set up used to investigate electrolysis of dilute sulphuric VI acid solution i Identify product X and Y 1 mark ii Write an equation for the reaction at the anode 1 mark iii Explain what happens to the solution after 2 hrs sometime 1 mark 3. Study the diagram below and use it to answer the questions that follow a. |
A 2 aq 2e A s 0.34 V N 2 aq 2e N s 0.76 V G aq 2e G s 0.00 V Y 2 aq 2e Y s 0.88 V L 2 aq 2e L s 2.16 V i Identify the strongest reducing agent 1 mark ii Explain why a solution containing A2 ions cannot be stored in a container made of metal N 1 mark iii The half cells of Y and L were combined to form an electrochemical cell. I Draw a well labelled diagram of the cell formed 3 marks II Calculate the e.m.f of the cell formed above 1 mark c The diagram below shows the set up used to investigate electrolysis of dilute sulphuric VI acid solution i Identify product X and Y 1 mark ii Write an equation for the reaction at the anode 1 mark iii Explain what happens to the solution after 2 hrs sometime 1 mark 3. Study the diagram below and use it to answer the questions that follow a. During the experiment, the following data was collected Volume of water 400 cm3 Initial temperature of water 23.00 C Final temperature of water 35.00 C Initial mass of lamp and ethanol 99.07 g Final mass of lamp and ethanol 98.23 g Specific heat capacity 4.2 kJ Kg-1 K- Calculate the; i Temperature change 1 mark ii Heat change for the reaction 2 marks iii Mass of ethanol that reacted 1 mark iv Molar enthalpy of combustion of ethanol C 12, H 1.0, O 16.0 2 marks www.freekcsepastpapers.comPage 169 b. |
I Draw a well labelled diagram of the cell formed 3 marks II Calculate the e.m.f of the cell formed above 1 mark c The diagram below shows the set up used to investigate electrolysis of dilute sulphuric VI acid solution i Identify product X and Y 1 mark ii Write an equation for the reaction at the anode 1 mark iii Explain what happens to the solution after 2 hrs sometime 1 mark 3. Study the diagram below and use it to answer the questions that follow a. During the experiment, the following data was collected Volume of water 400 cm3 Initial temperature of water 23.00 C Final temperature of water 35.00 C Initial mass of lamp and ethanol 99.07 g Final mass of lamp and ethanol 98.23 g Specific heat capacity 4.2 kJ Kg-1 K- Calculate the; i Temperature change 1 mark ii Heat change for the reaction 2 marks iii Mass of ethanol that reacted 1 mark iv Molar enthalpy of combustion of ethanol C 12, H 1.0, O 16.0 2 marks www.freekcsepastpapers.comPage 169 b. Use the information in the table below to answer the questions that follow Na g Cl- g NaCl s H1 776 kJ Mol Na g aq Na aq H2 390 kJ Mol Cl- g aq Cl- aq H3 384 kJ Mol i Give the name of 2 marks H1 .. H3 .. ii Using an energy cycle diagram, calculate the molar enthalpy of solution of sodium chloride 3 marks 4. Study the flow diagram below and use it to answer the questions that follow. A. Name substance; H , T F 3 marks b. State the conditions for 2 marks i. Step 1 ii. Step 2 c. Write an equation for the reaction in 2 marks i. Step 6 ii. Step 5 d. Draw the structural formula of substance M 1 mark e. |
Describe three successive tests he would carry out to confirm the solid is zinc and give the observations expected in each test. 3marks Test Procedure Expected observation 1 2 3www.freekcsepastpapers.comPage 171 7. The diagram below shows the laboratory preparation of ammonia gas. Study it and use it to answer the questions that follow. A. Name the reactants used 1 mark b. Give the role of calcium oxide 1 mark c. State 2 physical properties of ammonia gas 1 mark d. Write an equation for the reaction 1 mark e. Ammonia reacts with oxygen in the presence of a catalyst to produce nitric V acid industrially. I Name the catalyst used 1 mark ii Describe how the product in e above is converted to nitric V acid 2 marks f. Ammonia and sulphuric VI acid are reacted to form a fertilizer. I Write an equation for the reaction. 1 mark ii Calculate the volume of ammonia required at STP to manufacture 1500kg of the fertilizer at STP N 14.0, H 1.0, S 32, O 16.0, MGV at STP 22.4L 3 marks www.freekcsepastpapers.comPage 172 MURANG A EXTRA COUNTY SCHOOLS EXAMINATION. Kenya Certificate of Secondary Education 233 3 Chemistry PAPER 3 PRACTICAL 1. You are provided with; solution P, potassium manganate VII solution Q, containing 6.3 g litre of dibasic acid H2X.nH2O Solution R, containing 4.0 g litre of Sodium hydroxide solution. You are required to determine: a The value of n in H2X.nH2O b How the rate of reaction of solution P with solution Q varies with change in temperature. Procedure 1 Fill the burette with solution Q. Pipette 25cm3 of solution R into a conical flask and titrate solution Q with solution R using phenolphthalein indicator. Record your results in table I below and repeat the titration two more times and complete the table: Table I. |
Phenolphthalein indicator 2. Source of heat 3. 2M Pb NO3 2 aq 4. 2M HNO3 aq 5. 0.5M Ba NO3 2 aq 6. 2M Ammonia solution 7. 2M NaOH 8. Acidified KMnO4 solution 9. 2M HCl aq NOTES 1. Solution Q is 0.05M oxalic acid 2. Solution P is 0.01M potassium manganate vii solution. 3. Solution R is 0.1M sodium hydroxide solution. 4. A hot Water bath prepared by placing about 200 cm3of water in a 250ml beaker. 5. Solid V mixture NH4 2SO4 and Al2 SO4 3 in the ratio 1: 1 6. Solid T is maleic acid crystals. 7. Acidified KMnO4 is made by dissolving 3.169 of the solid KMnO4 in about 500 cm3of 2M H2S04 acid and diluting to one litre of solution. Www.freekcsepastpapers.comPage 187 MUMIAS WEST JOINT EVALUATION TEST, 2023 Kenya Certificate of Secondary Education 233 1 CHEMISTRY Paper 1 Theory TIME: 2 HOURS 1. A mixture of magnesium powder and copper powder was reacted with dilute hydrochloric acid. The solution was then filtered. Name: a i The residue 1mk ii The filtrate 1mk b Write an ionic equation for the reaction that takes place 1mk 2. Aluminium chloride solution changes the blue litmus paper red. Explain this observation 2mks 3. The diagram below shows the set-up that can be used to prepare and collect oxygen gas. Study it and answer the questions that follow. A Identify two mistakes from the diagram which must be corrected for one to collect dry oxygen gas 2mks b What property of oxygen gas makes it possible to be collected over water? 1mk 4. The table below gives information on four elements by letters K, L, M and N. Study it and answer the questions that follow. |
1mk 4. The table below gives information on four elements by letters K, L, M and N. Study it and answer the questions that follow. The letters do not represent the actual symbol of the elements. Element Electron arrangement Atomic radius nm Ionic radius nm Q 2.8.2 0.136 0.065 R 2.8.7 0.099 0.181 S 2.8.8.1 0.203 0.133 T 2.8.8.2 0.174 0.099 a Which two elements have similar chemical properties? Explain 2mks b What is the most likely formula of the oxide of R? 1mk c Which element is a non-metal. Explain 1mk 5. A fixed mass of a gas has a volume of 250cm3 at a temperature of 270C and 750mmHg pressure. Calculate the volume the gas would occupy at 420C and 750mmHg pressure. 3mks 6. Zinc metal and Hydrochloric acid react according to the following equation Zn s 2HCl aq ZnCl2 aq H2 g 1.96g of zinc were reacted with 100cm3 of 0.2M Hydrochloric acid, a Determine the reagent that was not enough 2mks www.freekcsepastpapers.comPage 188 b Calculate the total volume of hydrogen gas that was liberated at S.T.P conditions Zn 65.4, molar gas volume 22.4 litres at S.T.P 1mks 7. A Explain how a sample of CH3CH2OH could be distinguished from a sample of CH3COOH by a chemical test 2mks b Give the name of the type of compound formed when the a above are reacted . 1mk 8. A polymer has the following structure a Draw the repeating unit of the polymer 1mk b A sample of this polymer is found to have a molecular mass of 5194. |
A Explain how a sample of CH3CH2OH could be distinguished from a sample of CH3COOH by a chemical test 2mks b Give the name of the type of compound formed when the a above are reacted . 1mk 8. A polymer has the following structure a Draw the repeating unit of the polymer 1mk b A sample of this polymer is found to have a molecular mass of 5194. Determine the number of monomers on the polymer H 1.0, C 12.0, N 14.0 2mks 9. Describe how the following reagents can be used to prepare lead II sulphate: Solid potassium sulphate, solid lead II carbonate, dilute nitric acid and distilled water. 3mks 10. Explain why the enthalpy of neutralization of ethanoic acid with sodium hydroxide is different from that of Hydrochloric acid with sodium hydroxide. 3mks 11. Use the information below to answer the questions that follow: Equation: Enthalpy of formation. I H2 g O2 g H2O l H1 -286kJmol-1 ii C s O2 g CO2 g H2 -394kJmol-1 iii 2C s 3H2 g O2 g C2H5OH l H3 -277kJmol-1 Calculate the molar enthalpy of combustion of ethanol, given that: C2H5OH l 3O2 g 2CO2 g 3H2O l 3mks 12. The structure shown below represent two cleansing agents A and B. Which cleansing agent would be more suitable for washing in water containing magnesium sulphate? Explain 2mks b Identify the Soapy detergent . 1mk 13. M grammes of a radioactive isotope decayed to 5 grammes in 100 days. The half life of the isotopes is 25 days. A What is meant by half life? |
M grammes of a radioactive isotope decayed to 5 grammes in 100 days. The half life of the isotopes is 25 days. A What is meant by half life? 1mks b Calculate the initial mass M of the radioactive isotope 2mks 14. Complete the diagram to show how a sample of dry ammonia gas can be prepared in the laboratory. 3mks 15. 30cm3 of hydrogen gas was exploded with 10cm3 of oxygen gas at room temperature and pressure. Calculate the total volume of the mixture at; a 1000C 2mks b 700C 1mk www.freekcsepastpapers.comPage 189 16. Study the scheme below and answer the questions that follow a Write the formula of the cation present in the yellow solution F 1mk b What property of chlorine is shown in step I 1mk c Write an equation for the reaction in step III 1mk 17. A student set up the experiment below to collect gas K. The glass wool was heated before heating the zinc powder. A Why was it necessary to heat the moist glass wool before heating the zinc powder 2mk b What observations were made in the test tube 1mk 18. Using dots and crosses to represent the outermost electrons, draw the structure to show the bonding in CO2. C 6, O 8 . 3mks 19. Calculate the mass of nitrogen IV oxide gas that would occupy the same volume as 10g of hydrogen gas at the same temperature and pressure. H 1.0, N 14.0, O 16.0 3mks 20. Below is a table of reduction potentials and voltage of some half cells. |
2mks 27. In an experiment to study the properties of concentrated nitric acid, a mixture of the acid and wood charcoal was heated in a boiling tube. A What observations were made? Explain your answer 2mks b Write an equation for the reaction that took place in the boiling tube 1mk www.freekcsepastpapers.comPage 191 MUMIAS WEST JOINT EVALUATION TEST, 2023 Kenya Certificate of Secondary Education 233 2 Chemistry PAPER 2 Theory TIME: 2 HOURS 1. Study the flow chart that follows and answer the questions that follow. A Name the following 3mrks i Reagent E and Reagent S ii Compound F iii Reagent G iv Compound B v Compound C vi Compound O b Name the type of reaction in steps 2, 4. 8 and 9. 2mrks c State any one condition necessary for steps 3, 4, 8 and 10 to take place 2mrks d Draw the structure of compounds P, F and O 3mrks e Steps 5 and 9 are similar and lead to the same products. State and explain one difference in the observations made when steps 5 and 9 are separately carried out. 2mrks f Write chemical equations for the reactions that take place in steps 2 and 8. 2mrks 2. A Distinguish between an element and a molecule. 2mks b The diagram below represents part of the periodic table. Use it to answer the questions that follow. The letters do not represent the actual symbols of the elements F C G H D E J K i Which metallic element shown on the table has the highest electrical conductance? Explain 2mks www.freekcsepastpapers.comPage 192 ii Write the formula of the compound formed between E and G 1mk iii How do the first ionization energies of elements C and D compare? Explain. 2mks iv The melting point of E and K are 1120oC and -34oC respectively. In terms of structure and bonding, explain why there is a large difference in the melting point of E and K. |
Explain. 2mks iv The melting point of E and K are 1120oC and -34oC respectively. In terms of structure and bonding, explain why there is a large difference in the melting point of E and K. 2mks v Indicate on the grid the position of element L which forms L3- ions with electronic configuration 2.8.8. 1mk vi Element J reacts with dilute sulphuric VI acid at room temperature to produce 0.4dm3 of gas. Determine the mass of J which was reacted with dilute sulphuric VI acid. Molar gas volume at rtp is 24dm3, relative atomic mass of J 27 3mks 3. The graph that follows shows the solubility curves for some three common salts. Study it and answer the questions that follow. A Which of the three salts has the highest solubility at 200C? 1mrk b Which of the three salts has the lowest solubility at 300C? 1mrk c State the temperature at which the solubility of sodium chloride is the same as that of potassium nitrate and state the solubility of these salts at this temperature. 2mrks d The solubility of potassium nitrate is 137g 100g of water at 700C and 110g 100g of water at 600C. The solubility of potassium chlorate is 32g 100g of water at 700C and 25g 100g of water at 600C. Predict what will happen when 100g of water containing 130g of potassium nitrate and 20g of potassium chlorate is cooled from 700C to 600C. 2mrks e 100g of water at 600C containing 100g of potassium nitrate and 22g of potassium chlorate v was cooled to 200C. All the crystals formed were filtered. I Calculate the mass of each salt filtered out. 2mrks ii Determine the composition of the solution at 200C after filtration. 2mrks iii Determine the total mass of the solution at 200C after filtration. 2mrks 4 a Define the following terms. 3mrks i. Enthalpy of formation. Ii. Enthalpy of combustion. |
A Identify the following substances 2mks i Solid A ii Gas D. iii Solid Q. iv Solution M. b Write a chemical equation for the reaction in step I. 1mk c Write chemical equation for the formation of the following compounds. 3mks i Solid G. ii Gas D. iii Light blue solution C. iv State the confirmatory test for oxygen gas. 1mk v Write the ionic equation for reaction taking place in process P. 1mk vi State two uses of oxygen. 2mks 7. A State Charles law 1mk b Complete the following table by interconverting the following temperatures and filling in the missing volumes assuming that the volumes apply to the same mass of gas at constant pressure. 5mrks Temperature in 0C Temperature in K Volume in litres 195 156 8 312 -234 c A certain gas occupies 700cm3 at -700C. If pressure remains constant, at what temperature in 0C will its volume increase by a factor of 3? 4mrkswww.freekcsepastpapers.comPage 195 MUMIAS WEST JOINT EVALUATION TEST, 2023 Kenya Certificate of Secondary Education 233 3 Chemistry PRACTICAL Paper 3 TIME: 2 HOURS 1. You are provided with: Sodium hydroxide labeled solution A 0.128M hydrochloric acid labeled solution B Carboxylic acid labeled solution C Solution D prepared by diluting 25cm3 of solution A with distilled water to 150cm3 of solution You are required to: i Standardize solution D with solution B ii Determine the ratio between sodium hydroxide, solution A and the carboxylic acid, solution C iii Determine the concentration of C in moles per litre. Procedure 1 Fill the burette with solution B. Pipette 25cm3 of solution D into 250cm3 conical flask. Add 2 drops of phenolphthalein indicator and titrate with solution B. Record your results in table 1 below. Repeat the titration two more times and complete the table. |
Add 2 drops of phenolphthalein indicator and titrate with solution B. Record your results in table 1 below. Repeat the titration two more times and complete the table. Table 1 4marks I II III Final burette reading cm3 Initial burette reading cm3 Volume of solution B used cm3 a Determine the average volume of solution B used. 1mark b Calculate the concentration in moles per litre of sodium hydroxide in : i Solution D 2marks ii Solution A 2marks PROCEDURE 2 Using a clean burette, place 16cm3 of solution C into a boiling tube. Take the initial temperature of the solution in the boiling tube and record it in the table 2. Using a clean measuring cylinder, measure 4cm3 of solution A into 100cm3 beaker and add it to solution C in the boiling tube. Stir the mixture immediately with the thermometer and record in Table 2 the maximum final temperature reached. Repeat the experiment with the other set volumes of solution C and A in Table 2 and complete it. Rinse the thermometer and the boiling tube with distilled water after each experiment. Table 2 6Marks Volume of solution C, cm3 16 12 8 6 4 2 Volume of solution A, cm3 4 8 12 14 16 18 Final temperature OC Initial temperature OC Change in temperature, c On the grid provided, plot a graph of change in temperature vertical axes against the volume of sodium hydroxide, solution A d From the graph, determine the volume of sodium hydroxide solution A required to neutralize the carboxylic acid 1mark www.freekcsepastpapers.comPage 196 e Calculate the volume of carboxylic acid, solution C used for neutralization 1mark f Calculate the: i Ratio between the volumes of solution A and C 2marks ii Concentration in moles per litre of carboxylic acid, solution C Assume the volume ratio is the same as the mole ratio 2marks 2. You are provided with solid E. Carry out the tests below and record your observations and inferences in the spaces provided. A Divide E into halves. |
Filter funnel 3. Pipette 25cm3 4. One pipette filler 5. 0.3g of solid G 6. Two 250ml conical flasks 7. About 120ml of solution A 8. About 100ml of solution B 9. About 60ml of solution C 10. About 100ml of solution D 11. One 10ml measuring cylinder 12. Thermometer -10 110OC 13. 100ml plastic beaker 14. Two boiling tubes 15. One test tube holder 16. 2 red and 2 blue litmus papers 17. 1g of solid E 18. 0.5g of solid F 19. 6 clean dry test tubes 20. About 500ml distilled water Access to the following: 1. 2.0M sodium hydroxide supplied with a dropper 2. 0.5M Lead II nitrate supplied with a dropper 3. Bunsen burner 4. Phenolphthalein indicator supplied with a dropper 5. 2M sulphuric VI acid 6. Bromine water supplied with a dropper 7. Acidified potassium manganate VII supplied with a dropper NOTES AND PREPARATION 1. Solution A is made by dissolving 48g of sodium hydroxide in 500cm3 of distilled water and diluting to make one litre. 2. Solution B is made by dissolving 12cm3 of concentrated hydrochloric acid in about 600cm3 of distilled water and diluting it to one litre. 3. Solution C is prepared by dissolving 76g of oxalic acid in 600cm3 of distilled water and diluting to one litre 4. Solution D is prepared by dissolving 4g of sodium hydroxide in 600cm3 of distilled water and diluting to one litre. 5. Solid G is NaHCO3 6. Solid E is calcium chloride 7. Solid F is benzoic acidwww.freekcsepastpapers.comPage 213 KIRINYAGA WEST SCHOOL BASED EXAMINATION, 2023 233 1 CHEMISTRY PAPER 1 Theory TIME: 2 HOURS Instructions to candidates a. Answer ALL the questions. B. Mathematical tables and electronic calculators may be used. |
100cm3 of oxygen diffuse through an opening in 10 seconds while 150cm3 of unknown gas takes 12 seconds. Calculate the molecular mass of gas x. O 16.0 3mks 6. In a titration experiment 25cm 3 of sodium hydroxide solution containing 8.0g per litre was required for complete neutralization of 0.245g of diabasic acid. Calculate the relative molecular mass of the acid. Na 23, O 16, H 1.0 3mks www.freekcsepastpapers.comPage 214 7. Use the information below and answer the questions that follow. A Identify solid x. 1mk b Name gas w. 1mk c Write an equation between yellow solid and sulphuric VI acid. 1mk 8. Oxide of M was found to react with dilute hydrochloric acid and potassium hydroxide. What type of oxide is M oxide? 1mk 9. A 100g of radioactive substance was reduced to 6.25g within 15.6 years. Calculate the half life of the substance. 2mks b Study the nuclear reaction given in the scheme below and answer the question that follow. C127 Write an equation for the nuclear reaction in step II. 1mk 10. The information below relates to elements D E F and H. The letters do not represent the actual symbols of the elements. I. E displaces H from an aqueous solution containing ions H. ii. Hydrogen gas reduces heated oxide of D but doesn t reduce heated oxide of H. iii. F liberates hydrogen gas from cold water but E doesn t. a Write an equation for the reaction between E and ions of H. Both B and D are in group II of the periodic table. 1 mk b Arrange the elements in order of their increasing reactivity. 1mk 11. The table below shows some information about elements A1, A2, A3 and A4 which are in the same group of the periodic table. Use the information to answer the questions that follow. Element 1st ionization energy kJ Mol A1 500 A2 420 A3 400 A4 520 i. What is meant by the term ionization energy? |
Use the information to answer the questions that follow. Element 1st ionization energy kJ Mol A1 500 A2 420 A3 400 A4 520 i. What is meant by the term ionization energy? 1mk ii. Select the most reactive element. Give a reason for your answer. 1mk iii. Arrange the element according to increase in atomic radii. 1mk 12. A factory uses 200kg of ammonia each day to produce 120kg of nitrogen II oxide. Calculate the percentage yield of nitrogen II oxide. 3mks 13. Dry hydrogen chloride gas was passed over heated iron turnings as shown in the diagram below. A What was observed in the combustion tube during the experiment? 1mk b Write down the equation for the reaction taking place in the combustion tube. 1 mk c Identify the colour of the flame D. 1mk Step 1 Step 2 Heat Iron fillings Dry hydrogen chloride Flame Dwww.freekcsepastpapers.comPage 215 14. A gaseous hydrocarbon contains 80 carbon by mass. Given that 2dm3 of the compound at r.t.p has a mass of 2.5g. Calculate the molecular formula of the compound. C 12, H 1, Molar gas volume at r.t.p 24dm3 3mks 15. A When potassium nitrate is heated it decomposes. Write a balanced equation for the thermal decomposition of potassium nitrate. 1mk b How would you test for the gas produced in the process? 1 mk c State one use of the gas formed on decomposition. 1mk 16. Study the scheme below and answer the questions that follow. A Identify gas C. 1 mk b State one disadvantage of using platinum asbestos catalyst. 1 mk c Give the most appropriate catalyst. 1 mk 17. Study the flow chart below and answer the questions that follow. I. Give; I. The name of process that takes place in step I and II. 1 mk Step I Step II 1 mk II. The name and formula of substance N. 1 mk ii. The relative molecular mass of K is 15680. Calculate the number of monomers that make up K. |
1 mk ii. The relative molecular mass of K is 15680. Calculate the number of monomers that make up K. 1mk 18. Below is a flow chart that shows the process of obtaining substance C from ammonia gas at an optimum temperature of 9000C and in presence of a catalyst. A Name raw materials used in Haber process. 1mk b Identify catalyst used to convert ammonia into substance c. 1mk c Write an equation leading to formation of substance C. 1mk 19. When hydrogen peroxide is mixed with little manganese IV oxide, a colourless gas is evolved. A Identify the gas. 1mk b What is the purpose of manganese IV oxide? 1 mk c How is the gas a above prepared in large scale? 1mk 20. Hydrogen sulphide gas was bubbled in a test tube containing a solution of Nitric V acid. A State and explain the observation that was made. 2mks b Write an equation for the reaction that took place. 1mk www.freekcsepastpapers.comPage 216 21. A Name two gaseous pollutants emitted from a car exhaust. 1mk b What is a pollutant? 1 mk 22. A In the space provided below draw a diagram to represent the apparatus that can be used to prepare hydrogen gas from a reaction of steam and metal x that is divalent. 2 mks b Write a balanced chemical equation for a above . 1 mk 23. The table below shows the relative molecular masses and the boiling points of; Explain why the boiling point of butan 1 ol is higher than that of butane. 2mks 24. Study the thermochemical equations below and answer the questions that follow. |
The table below shows the relative molecular masses and the boiling points of; Explain why the boiling point of butan 1 ol is higher than that of butane. 2mks 24. Study the thermochemical equations below and answer the questions that follow. C s O 2 g ----- CO 2 g H C -39.3kJ Mol H 2 g O 2 g ------ H2O g H C - 286kJ Mol 3C s 4H 2 g ------- C3H 8 g Hf 103.6kJ Mol Calculate the heat of combustion of propane C3H8 3mks 25. Study the figure below and answer the questions that follow. I. Name process T. 1 2 mk ii. Name the substance represented by R. 1 2 mk iii. Write the formula of complex ion present in solution W. 1 mk iv. Write the equation for the reaction taking place in step P. 1 mk 26. The following equations show the dissociation of two acids. I. rH aq r- aq H aq II. PH aq P- aq H aq a Which of the two acids is a weak acid? Give a reason for your answer. 2 mks b Give a difference between a dilute acid and weak acid. 1mk 27. Element Z has three isotopes 36Z, 38Z 40Z and the abundance of the element is 0.34 , 0.06 and 99.6 respectively. Calculate the relative atomic mass of Z. 2mks 28. Describe the chemical tests that would distinguish between C3H8O and C2H4O2. 2 mks 29. Study the information given in the table below and answer the questions that follow. |
Describe the chemical tests that would distinguish between C3H8O and C2H4O2. 2 mks 29. Study the information given in the table below and answer the questions that follow. Half reactions Electrode potential E V P 2 aq 2e - P s 0.34 Q aq e- Q s 0.80 R 2 aq 2e- R s -2.87 V 2 aq 2e- V s -0.13 W 2 aq 2e- W s -2.71 U3 aq e- U 2 s 0.68 Construct an electrochemical cell that will produce the largest e.m.f. 3mks www.freekcsepastpapers.comPage 217 KIRINYAGA WEST SCHOOL BASED EXAMINATION, 2023 233 2 CHEMISTRY PAPER 2 Theory TIME: 2 HOURS INSTRUCTIONS TO CANDIDATES 1. Answer all questions in the English. 2. Mathematical tables and electronic calculators may be used. 3. All working must be clearly shown where necessary. 1. A The grid below shows part of the periodic table. Study it and answer the questions that follow. The letters do not represent the actual symbols of the elements. I State an element that can form an ion with a charge of -2. 1 2mk ii What type of structure will a chloride of Q have? 1 2mk iii Explain how the reactivities of V and W compare. 2mks iv Compare the atomic radius of T and S. Explain. 2mks v 2.5g of a Q react completely with 1.2dm3 of gas R at s.t.p I. Write a balanced equation for the reaction between Q and R. 1mk II. Determine the R.A.M of Q Molar Volume of a gas at s.t.p 22.4dm3 2mks b Study the information given below and answer the questions that follow. |
Write a balanced equation for the reaction between Q and R. 1mk II. Determine the R.A.M of Q Molar Volume of a gas at s.t.p 22.4dm3 2mks b Study the information given below and answer the questions that follow. Formula of compound Nacl MgCl2 Al2Cl6 SiCl4 PCl5 Boiling point 0C 1470 1420 Sublimes 60 75 Melting point 0C 800 710 800 -70 90 i Why is the fomula of aluminium chloride given as Al2Cl6 and not AlCl3. 1mk ii Give a chloride that is a liquid at room temperature. Explain 1mk iii Explain the difference in melting point of NaCl and PCl5. 2mks 2. Study the flow chart below and answer the questions that follow. Www.freekcsepastpapers.comPage 218 a Identify i Substance F 1 2mk ii Liquid D 1 2mk iii Gas Y 1 2mk iv Gas X 1 2mk b Name and draw the structure of compounds; b T 2mks c X 2mks c Identify the type of reaction and condition for changing X to CH3CH2Cl. 1mk d Name the type of reaction that i Leads to the formation of CH3CH2COOH. 1mk ii Leads to the formation of substance W. 1mk d Write an equation that results in formation of product Z. 1mk e What is the effect on the continued use of substance T to the environment? Explain. 2mks 3. A The diagram below is part of a set up used to prepare and collect dry chlorine gas. I Complete the diagram to show how dry chlorine gas can be collected. 2mks ii Name another substance that can be used instead of Manganese IV oxide. 1mk ii Write an equation for the following I. Chlorine reacting with Iron. 1mk II. Chlorine reacting with hot concentrated sodium hydroxide solution. |
Chlorine reacting with Iron. 1mk II. Chlorine reacting with hot concentrated sodium hydroxide solution. 1mk iv An oxide of chlorine of mass 1.83g was found to contain 1.12g of oxygen. Determine the empirical formula of the oxide. O 16, Cl 35.5 3mks v Other than manufacture of hydrochloric acid name two other uses of chlorine. 1mk b Two solutions containing cations P and Q were separately added to solutions containing chloride ions. In both cases a white precipitate was formed. To each a few drops of nitric V acid were added. The chloride compound of P and Q warmed. The chloride compound of Q dissolved while that of P did not. I Identify the metal ions of P and Q. 1mk ii Write ionic equations for the reaction that occurred when cations of P and Q reacted with chloride ions. 2mks 4. A The set up below was used during electrolysis of aqueous iron II sulphate using inert electrodes. Study it and answer the questions that follow. Concentrated HCl Manganese IV oxide Aqueous Iron II Sulphatewww.freekcsepastpapers.comPage 219 i Name a suitable material for the electrodes. 1mk ii Identify the cations present in the solution. 1mk iii On the diagram label the cathode. 1mk iv Write an ionic equation for the reaction that took place at the anode. 1mks v Explain the changes that occurred in the concentration of iron II sulphate solution during the experiment. 2mks b The information below is about the standard reduction potentials of four half cells. Study it and answer the questions that follow. Letters do not represent the actual symbols of the elements. Half cell E value V F2 aq 2e- 2F- aq 0.54 G2 aq 2e- G s -0.44 H2 aq 2e- H s 0.34 2J aq 2e- J2 g 0.00 i Identify the strongest reducing agent. Explain. |
Letters do not represent the actual symbols of the elements. Half cell E value V F2 aq 2e- 2F- aq 0.54 G2 aq 2e- G s -0.44 H2 aq 2e- H s 0.34 2J aq 2e- J2 g 0.00 i Identify the strongest reducing agent. Explain. 1mk ii Write the equation for reaction which takes place when solid G is added to a solution containing H2 aq ions 1mk iii Calculate the E value of the reaction in ii above. 1mk iv If element G becomes the reference electrode calculate the new standard electrode potential for element H. 1mk c Calculate the mass of chlorine liberated during the electrolysis of molten sodium chloride when a current of 2A is passed for 4 minutes. Cl 35.5 2mks 5. A Define the following terms. I Half-life 1mk ii Nuclear fission 1mk b The table below gives percentage of a radioactive isotope of Bismuth that remains after decaying at different times. Time in min 0 6 12 22 38 62 100 Percentage of Bismuth 100 81 65 46 29 12 3 i On a graph paper plot the percentage of Bismuth remaining against time. 3mks ii Using the graph determine the original mass of the Bismuth Isotope given that the mass that remained after 70 minutes was 0.16g. 2mks c Radioactive Carbon 14 decays by emitting beta particle to form N-14, write a nuclear equation for the reaction. 1mk d State one use of radioactive Isotope in: i Medicine 1mk ii Industry 1mk 6. An excess Zinc powder was added to 200cm3 of Copper II sulphate solution. The mixture was stirred with a thermometer and the temperature noted. The temperature rose from 220C to 28.20C and 1.58g of Copper was deposited. A Write ionic equation for the reaction that took place. |
The mixture was stirred with a thermometer and the temperature noted. The temperature rose from 220C to 28.20C and 1.58g of Copper was deposited. A Write ionic equation for the reaction that took place. 1mk b Why was excess Zinc powder used? 1mk c Besides the temperature rise state two other observations made as the mixture was stirred. 2mks d Using the information above calculate the molar enthalpy of deposition of copper by zinc. R.A.M of copper 63.5, Specific heat capacity 4.18KjKg-1 k-1 4mks e Using the result of d above draw an energy level diagram of deposition of copper by zinc. 2mks f If this experiment was repeated using Iron fillings instead of zinc powder how would you expect the molar enthalpy of displacement to compare with one obtained in d above. Explain. 2mks www.freekcsepastpapers.comPage 220 4. Iron is obtained from haematite using a blast furnace shown in the figure below. A State two raw materials required for the production of iron other than iron oxide. 1mk b Write an equation for the reaction in which carbon IV oxide is converted to carbon II oxide. 1mk c Explain why the temperature in the region marked Y is higher than that of the incoming hot air. 2mks d State one physical property of molten slag other than density that allows it to be separated from molten iron as shown. 1mk e One of the components of the waste gases is nitrogen IV oxide. Describe the adverse effects it has on the environment. 2mks f Iron from the blast furnace contains 5 carbon. I Describe how the car bon content is reduced. 2mks ii Why is it necessary to reduce the carbon content? 1mk www.freekcsepastpapers.comPage 221 KIRINYAGA WEST SCHOOL BASED EXAMINATION, 2023 233 3 CHEMISTRY PAPER 3 CONFIDENTIAL In addition to the sittings and apparatus found in a chemistry laboratory, each candidate will require the following; - 120 cm3 of solution T. |
I Describe how the car bon content is reduced. 2mks ii Why is it necessary to reduce the carbon content? 1mk www.freekcsepastpapers.comPage 221 KIRINYAGA WEST SCHOOL BASED EXAMINATION, 2023 233 3 CHEMISTRY PAPER 3 CONFIDENTIAL In addition to the sittings and apparatus found in a chemistry laboratory, each candidate will require the following; - 120 cm3 of solution T. - 100 cm3 of solution E - 100cm3 of solution F - 3 cm of polished magnesium ribbon labelled solid M - 1 label - 50 ml burette - 25 ml pipette - 2 conical flasks - Thermometer - White file - Complete stand - 250ml volumetric flask - White plain piece of paper. -. Distilled water. -. 50ml measuring cylinder. -. 10ml measuring cylinder. -. 100ml plastic beaker - Stop watch - Filter funnel. -. 1 boiling tube. -. 5 test tubes in a rack. -. 0.2g of solid sodium hydrogen carbonate approximate . -. Solid K - Solid Q - Filter funnel - Test tube holder - 1 filter paper. -. Metallic spatula. -. Source of heat Access to: - Bunsen burner. -. 2M sodium hydroxide solution with a dropper. -. 0.5 M sodium sulphate solution with a dropper. -. 0.5M barium nitrate solution with a dropper. -. 0.5M lead ii nitrate solution with a dropper. -. Acidified potassium manganate VII solution with a dropper. -. Acidified potassium dichromate VI solution with a dropper. -. Phenolphthalein indicator with a dropper. NOTES 1. Solid Q , 1 g zinc chloride 2. Solid K, crushed paracetamol panadol 0.5g 3. Solution E is 2M hydrochloric acid. 4. Solution F is 0.2M sodium hydroxide solution. 5. Solution T is 0.15M sodium thiosulphate. 6. Solid M is 3 cm polished magnesium ribbon. |
Solution T is 0.15M sodium thiosulphate. 6. Solid M is 3 cm polished magnesium ribbon. Www.freekcsepastpapers.comPage 222 KIRINYAGA WEST SCHOOL BASED EXAMINATION, 2023 233 3 CHEMISTRY PAPER 3 Practical TIME: 2 HOURS 15 MINUTES Instructions to candidates a. Answer ALL the questions. B. Mathematical tables and electronic calculators may be used. C. All working MUST be clearly shown where necessary. 1. You are provided with; - Solution E, containing 2M hydrochloric acid. -. Solution F, containing 0.2M sodium hydroxide. -. Solid M, Magnesium ribbon. -. Solution T, containing 0.15M sodium thiosulphate. You are required to; i. Determine molar heat of reaction between magnesium and hydrochloric acid. Ii. Determine rate of reaction between hydrochloric and sodium thiosulphate. Procedure 1 i Place 20cm3 of solution E into 100ml plastic beaker and measure the intial temperature of solution E. Initial temperature of solution E 0C 1 2 mk ii Add all the solid M provided to solution E and stir the mixture with a thermometer. Measure the maximum temperature of the solution. Maximum temperature of the solution 0C. 1 2 mk iii Transfer the resulting solution formed into a 250ml volumetric flask, add distilled water upto the mark. Shake the mixture well and label it as solution G. iv Fill the burette with solution G upto 0.0cm3 mark. Pipette 25cm3 of solution F into a clean conical flask and add 2-3 drops of phenolphthalein indicator. V Titrate solution G against solution F until the pink colour turns colourless. Repeat the titration two more times and record the values in table 1 below. A Table 1 4 mks Experiment i ii iii Final burette reading Initial burette reading Volume of solution G used cm3 b Calculate the average volume of solution G used. 1 mk c Calculate the number of moles of sodium hydroxide solution F used. 1 mk d Calculate the number of moles of hydrochloric acid; i. In the average volume of solution G used. |
A Explain the role of common salt in defrosting ice on roads in ice cold countries. 1 mark b Explain why the long-term effects of use of common salt is costly to motorists. 1 mark 13. Given the equation below NH3 aq H2O l NH4 aq OH- aq Identify the species that acts as; H HHHwww.freekcsepastpapers.comPage 234 i A base. Explain 1 mark ii An acid. Mark 14. A State Grahams law of diffusion. 1mark b The rate of diffusion of Sulphur IV oxide gas through a porous material is 40cm3s 1. Calculate the rate of diffusion of carbon IV oxide gas through the same porous material S 32,O 16,C 12 2 marks 15. Describe how a solid sample of lead II chloride can be prepared using the following reagents: dilute nitric acid, dilute hydrochloric acid and lead carbonate 3 marks 16. The production of ammonia is given by the equation i State and explain the effect of addition of dilute hydrochloride acid on equilibrium. 2 marks ii Explain the effect of increase in temperature on the yield of ammonia. 2 marks 17. Cr2O72- 14 H aq 6Fe2 Cr23 7H2O l 6Fe3 . The above equation show a redox reaction a Calculate the oxidation state of chromium in Cr2O72- 2 marks b What is the role of H in the above reaction. 1 mark 18. A Define the standard heat of formation. 1 mark b Draw energy cycle diagram to show how the standard heat of formation of ethanol C2H5OH can be determined from standard heats of combustion of its elements. 2 marks c Given that HC C - 393kJmole-1, HC H2 -286kJmole-1 and HC C2H5OH - 1368kJmole-1. Calculate the enthalpy of formation of C2H5OH. 2 marks 19. |
2 marks c Given that HC C - 393kJmole-1, HC H2 -286kJmole-1 and HC C2H5OH - 1368kJmole-1. Calculate the enthalpy of formation of C2H5OH. 2 marks 19. 3.78g of a hydrated salt of iron II sulphate, FeSO4, in H2O were heated until all the water of crystallization was driven off. The anhydrous salt left had a mass of 1.52g. Determine the formula of the hydrated salt. Fe 56, S 32, H 1, O 16 3 marks 20. A steady current of 0.2 Amperes was passed through molten silver bromide for 80 minutes. A Calculate the quantity of electricity that passed through the set up. 1 mark b Calculate the mass of product deposited at the cathode. 1F 96500C; Ag 108, Br 80 2 marks c If a sample of cobalt has an activity of 1000 counts per minute, determine the time it would take for its activity to decrease to 62.50 if the half-life of the element is 30 minutes. 2 marks 21. The apparatus set up below was used to prepare an anhydrous solid P a Write an equation for formation of solid P 1 mark b Suppose the gas used in the set up was dry hydrogen chloride gas; what would be the product obtained after the reaction? Give a reason for your answer. 1 mark 22. Aluminium is obtained from the ore with the formula Al2O3. 2H2O. The ore is first heated and refined to obtain pure aluminium oxide Al2O3 . The oxide is then electrolysed to get Aluminium and oxygen gas using carbon anodes and carbon as cathode. A Give the common name of the ore from where aluminium is extracted from. Mark b What would be the importance of heating the ore first before refining it? 1 mark c The refined ore has to be dissolved in cryolite first before electrolysis. Why is this necessary? |
Mark b What would be the importance of heating the ore first before refining it? 1 mark c The refined ore has to be dissolved in cryolite first before electrolysis. Why is this necessary? 1 mark d Why are the carbon anodes replaced every now and then in the cell for electrolysing aluminium oxide? 1 mark 23. Use the cell representation below to answer the questions that follow V s V3 aq Fe2 aq Fe s i Write the equation for the cell reaction 1 mark ii If the E.M.F of the cell is 0.30 volts and the E value for V3 aq V s is -0.74V, calculate the E of Fe2 aq Fe s 2 marks 24. When 50cm3 1M potassium hydroxide was reacted with 50cm3 of 1M hydrochloric acid, the temperature rose by 80C. When the same volume of Potassium hydroxide was reacted with 50cm3 of 1M Pentanoic acid, the temperature rose by 30C. www.freekcsepastpapers.comPage 235 i Give reasons for the above difference in temperature. 2 marks ii Write an equation to show dissociation of pentanoic acid? 1 mark 25. The following is structural formula of polyester. OCHOCOO2CH2CH2C a Draw the structural formula and name the alkanoic acid and alkanol that react to form the polymer. 2 marks b Give one use of polyester. 1 mark 26. A heavy metal P was dissolved in dilute nitric acid to form a solution of compound P NO3 2. Portions of the resulting solution were treated as follows: a To the first portion a solution of dilute hydrochloric acid is added, where a white precipitate S is formed, which dissolves on warming. B The second portion is treated with two drops of 2M Sodium hydroxide solution where a white precipitate T is formed. The white precipitate dissolved in excess sodium hydroxide to form a colourless solution. C A solution of potassium iodide is added to the third portion where a yellow precipitate U is formed. |
B The second portion is treated with two drops of 2M Sodium hydroxide solution where a white precipitate T is formed. The white precipitate dissolved in excess sodium hydroxide to form a colourless solution. C A solution of potassium iodide is added to the third portion where a yellow precipitate U is formed. D When the resulting solution is evaporated to dryness and heated strongly a yellow solid V is formed and a brown gas W and a colourless gas X are formed. Identify the substances P, S, T, U, V, W. 3 marks 27. The graphs below were drawn when 15g of marble chips in different physical states were reacted with 50cm3 of 2M Hydrochloric acid. They are drawn by measuring the volume of carbon iv oxide produced with time. A Which curves corresponds to the reactions involving powdered calcium carbonate and large sized marble chips with the dilute acid? I Powdered calcium carbonate mark ii Large sized calcium carbonate mark b All the graphs eventually flatten out at the same level but at different time. Why do the graphs flatten out at the same level? 1 mark c Why is curve A very steep at any given point compared to the other curves? 1 mark Volume of Co 50Curve A Curve BCurve CTime4050www.freekcsepastpapers.comPage 236 28. Sodium thiosulphate was reacted with dilute hydrochloric acid in a round bottomed flask as shown below. The gas evolved was collected by downward delivery in a gas jar. A Write an equation to show the reaction going on in the reaction in vessel. 1 mark b State the observation noted on the filter paper. Give a reason for your answer. 1 mark c Give a reason why the filter paper soaked in the acidified potassium chromium VI is used at the top of the flask 1 mark Dilute hydrochloric acidCardboard covermoisty filter paper soaked in acidified potassium chromium vi solutionsodium thiosulphatewww.freekcsepastpapers.comPage 237 FORM IV TRIAL 2 EXAMINATIONS, 2023 Kenya Certificate of Secondary Education K.C.S.E 233 2 CHEMISTRY Paper 2 THEORY Time: 2 Hours 1. |
State how the two substances differ as conductors of electric current. 2marks 2. Study the flow chart below and answer the questions that follow. Www.freekcsepastpapers.comPage 238 R CONa O a Name ore N 1mark b Explain why the ore is first dissolved in excess sodium hydroxide solution. 1mark c Name the major compound present in the residue. 1mark d Give the formula of the aluminium compound present in solution 1mark e i Explain how to obtain aluminium hydroxide from solution X 1mark ii Write equation for reaction that takes place in e above 1mark iii What is the role of cryolite in the extraction of aluminium. 1mark f Aluminium is a good conductor of electricity. State two uses of aluminium based on this property. 2marks g If sodium carbonate is added to aluminium nitrate solution, effervescence occurs. Explain. 2marks 3. Study the flow chart below and answer the questions that follow. A Give the names of the following i Compound K 1mark ii Substance Y 1mark iii Product obtained in step 4 1mark b Identify the type of reaction that takes place in step 1 and give one other condition necessary for the reaction other than the temperature indicated. Type of reaction . 1mark Condition 1mark c Draw the structural formula of the following i Polymer M 1mark ii Acid Q 1mark d Give the industrial application for the reaction in step 3 1mark e Write chemical equations for the reactions in step 6 and step 7. 2marks f The following are structures of two cleansing agents. R SO Na In the table below, give one advantage and one disadvantage of each of them. 2marks Cleansing Agent Advantage Disadvantage R-COO-Na R-OSO3-Na 4. The standard reduction potentials for five half cells are shown in the table below. Study it and answer the questions that follow. The letters do not represent the actual symbol of elements . |
The standard reduction potentials for five half cells are shown in the table below. Study it and answer the questions that follow. The letters do not represent the actual symbol of elements . Elements E Volts i 09.1 aqaqAeA ii 13.022 SaqQeQ iii 37.222 SaqReRwww.freekcsepastpapers.comPage 239 iv 34.022 SaqYeY v 00.0222 SaqSeS I a With a reason, identify the strongest reducing agent. 1mark b Which half-cell is likely to be hydrogen? 1mark c Write an equation for the reaction between two half cells in ii and IV . 1mark d Calculate the e.m.f of the cell in c above. 2mark II. The diagram below represents a mercury cell that can be used in the industrial manufacture of sodium hydroxide. Study it and answer the questions that follow:- a Name: i Raw material introduced at 2. Mark ii Another substance that can be used in the cell instead of graphite. Mark b Identify the by-product that comes out at I. 1 mark c Write an equation for the reaction: - i That occurred at the anode. 1 mark ii In which sodium hydroxide was produced. 1 mark d Give two reasons why mercury is recycled. 2 marks e State one use of sodium hydroxide 1mark 5. The flow chart below illustrates two industrial processes. Haber process and the contact process. A Name the process of obtaining nitrogen from atmospheric air. 1mark b List TWO sources of obtaining large volumes of hydrogen for industrial use. 2 marks c Write equation for Haber process. 1mark d Name the catalysts for: 1mark i Haber process ii Contact processwww.freekcsepastpapers.comPage 240 e Identify substances: 1mark i D . |
1mark b List TWO sources of obtaining large volumes of hydrogen for industrial use. 2 marks c Write equation for Haber process. 1mark d Name the catalysts for: 1mark i Haber process ii Contact processwww.freekcsepastpapers.comPage 240 e Identify substances: 1mark i D . Ii C . F Give ONE major use of compound D 1mark g Write an equation for dilution of C with water. 1mark h A farmer has three plots each measuring 0.25 acres. He applied nitrogenous fertilizers as follows. -. Plot A 250 kg of ammonium phosphate - plot B 250 kg of urea CO NH2 2 - Plot C 250kg of ammonium nitrate Which plot received the highest nitrogen content? 3marks H 1, N 14, 0 16. P 31, C 12. 6. Study the diagram below and answer the questions which follow. I State two observations made when hydrogen gas pass over hot Lead II oxide. 2marks ii Write the equation for the reaction which occurs in the combustion tube. 1mark iii What property of hydrogen is shown in the experiment above. 1mark iv Identify liquid M and describe the test for its purity 2marks v What would be observed if MgO was used instead of Lead II Oxide: Explain 2marks vi What is the colour of the flame 1mark vii Write a chemical equation of the reaction producing the flame. 1mark vii Apart from hydrogen peroxide, state two other reagents that can be used to prepare oxygen gas. 1mark viii Write an equation to show how hydrogen gas is formed from the reagents chosen in vii above. 1mark 7. I. |
Repeat procedure II three more times and record the temperatures in table 1. RETAIN the contents of the boiling tube for use in PROCEDURE II. TABLE 1 Volume of water in the boiling tube cm3 Crystallization temperature C Solubility of solid P in g 100 g of water 4 6 8 10 12 4marks a Complete table 1 above by working out the solubility. 1 mark b On the graph provided, plot a graph of solubility of solid P against crystallization temperature. 3marks c From the graph, determine; i The solubility of solid P at 50 C 1 mark ii The temperature at which 65 g of solid P would dissolve in 100 g of water 1 mark Procedure II i Transfer the contents of the boiling tube from PROCEDURE I into a clean 250 ml volumetric flask. Ii Add distilled water up to the mark iii Label the resulting solution as solution P iv Fill the burette with solution P v Pipette 25cm3 of solution L into a conical flask. Add three drops of phenolphthalein indicator vi Titrate solution P against solution L to an accurate end point. Record your results in table 2 below. 4 marks TABLE 2 1 2 3 Final burette reading Initial burette reading Volume of solution P used cm3 www.freekcsepastpapers.comPage 243 a Calculate Average volume of solution P used. 1mark b i Moles of solution L used. 1 mark ii Moles of solution P used. 1 mark iii Moles of solution P in 250 cm3 of solution P 1 mark iv The relative formula mass of P. 1 mark c Determine the value of n in the formula; H2C2O4.nH2O H 1, C 12, O 16 2marks 2. You are provided with solid E. Carry out the experiments below. Write your observations and inferences in the spaces provided. Place all solid E into a boiling tube. Add about 20cm3 of distilled water and shake. Retain the contents of the boiling tube. |
Place all solid E into a boiling tube. Add about 20cm3 of distilled water and shake. Retain the contents of the boiling tube. Observations inferences 1 mark 1 mark Use 2cm3 of solution E, in a test tube in each experiment i, ii, iii, iv and v i. To experiment i, Add two drops of aqueous Sulphuric vi acid Observations inferences 1 mark 1 mark ii. To experiment ii, add NaOH solution drop wise till in excess. Observations inferences 1 mark 1 mark iii. To experiment iii, dip a stirring rod into the solution, place the rod in a non-luminous flame. Observations inferences 1 mark 1 mark iv. To experiment iv, add two drops of lead ii nitrate solution. Observations inferences 1 mark 1 mark v. To experiment v, add a piece of aluminium foil followed by sodium hydroxide solution and warm. Test the gas given out with litmus papers. Observations inferences 2 marks 1 mark 3. You are provided with liquid Q. carry out the tests below. Write your observations and inferences in the spaces provided. I . To 2 cm3 of liquid Q in a test tube, add universal indicator Observations inferences 1 mark 1 mark ii . Place 3 drops of liquid Q on a watch glass and ignite. Observations inferences 1 mark 1 mark iii . To 2 cm3 of liquid Q in a test tube , add two or three drops of acidified potassium dichromate VI and warm Observations inferences 1 mark 1 markwww.freekcsepastpapers.comPage 250 GATUNDU SOUTH JOINT EXAMINATION, 2023 Kenya Certificate of Secondary Education 233 1 CHEMISTRY PAPER 1 THEORY 2 HOURS Answer all the questions. 1. Describe the non luminous flame of a Bunsen burner and give a reason why it s preferred when heating substances in the laboratory. 3mks 2. The table below gives some properties of gases M and N Describe how one would obtain a sample of gas N from a mixture of gases M and N 2mks 3. The following results were obtained trying to determine the solubility of copper II sulphate in water at 400 C. |
Hydrogen sulphide gas was bubbled through a solution of zinc nitrate for some time. I State the observation made. 1mark ii Where should the experiment be carried out and why? 1mark iii Write the equation of the reaction that occurs 1mark 25. 25cm3 of 0.12M Potassium Hydroxide solution required 30cm3 of a solution of a dibasic acid H2X for complete neutralization. The acid contained 3.15g per 500cm3 solution. Calculate i The molarity of the acid solution. 2marks ii The relative molecular mass of the acid. 1mark www.freekcsepastpapers.comPage 254 26. In the Haber process, the industrial manufacture of ammonia is given by the following equation; i Give one source of the Hydrogen that is used in the process 1 mk ii Name the catalyst used in the above reaction iii What is the effect of increasing temperature on yield of ammonia? Explain. 1 mk 27. Study the diagram shown below to answer the questions that follow. The curve shows heating curve of water in the laboratory. I At what temperature does the water boil? 1mark ii Is the curve for a pure water or impure water? Give a reason for your answer. 2marks iii Give the effect of impurities on the boiling point of water. 1mark 2 23ggHN 1 KJmolHNHgwww.freekcsepastpapers.comPage 255 GATUNDU SOUTH JOINT EXAMINATION, 2023 Kenya Certificate of Secondary Education 233 2 CHEMISTRY PAPER 2 THEORY 2 HOURS INSTRUCTIONS TO CANDIDATES Answer ALL questions. Mathematical tables and electronic calculators may be used. All workings must be clearly shown where necessary. 1. The flow chart given shows an analysis of mixture K that contains two salts. Study it and answer the question that follows. A Name substances L, M and N 1 marks b What condition is necessary for step 1 to take place? |
The flow chart given shows an analysis of mixture K that contains two salts. Study it and answer the question that follows. A Name substances L, M and N 1 marks b What condition is necessary for step 1 to take place? 1mark c State the colour changes that the metal oxide undergoes when hot and cold 1mark d Write down an equation to show how i Solution N is formed 1mark ii Colourless solution A and NH3 aq are formed. 1mark e When excess NaOH aq is added to a solution N a white precipitate is formed which subsequently dissolves. Give the name and formula of the complex ion formed 1mark f Ammonia gas bubbled into water forms a solution which conducts electricity whereas the solution formed when it is bubbled through methylbenzene does not. Explain. 2 marks g Boilers used for boiling hard water are normally covered with boiler scales after sometime. I What is the chemical name for boiler scales? 1 mark ii Describe how the boiler scales can be removed? 1 marks www.freekcsepastpapers.comPage 256 2. A The diagram below shows a set-up of apparatus that can be used to prepare nitrogen IV oxide. Study it and use it to answer the questions that follow i Write the equation for the reaction that takes place in the boiling tube. 1mark ii Explain why lead II nitrate is preferred over other metal nitrates in this experiment. 2marks iii Describe how gas A can be identified. 1mark iv Name liquid B 1mark b Consider the following reaction: N2 g 3H2 g 2NH3 g H 75KJ Sketch an energy level diagram showing the relative activation energies for the catalysed and uncatalysed reactions using the axes below. 2 marks Energy KJ Reaction path c Given that the lattice energy of calcium chloride is 2237kJmol 1 and the hydration energy of Ca2 aq -1650kJmol 1 and Cl aq -364kJmol 1. Calculate the enthalpy of solution of calcium chloride. |
1mark iv Name liquid B 1mark b Consider the following reaction: N2 g 3H2 g 2NH3 g H 75KJ Sketch an energy level diagram showing the relative activation energies for the catalysed and uncatalysed reactions using the axes below. 2 marks Energy KJ Reaction path c Given that the lattice energy of calcium chloride is 2237kJmol 1 and the hydration energy of Ca2 aq -1650kJmol 1 and Cl aq -364kJmol 1. Calculate the enthalpy of solution of calcium chloride. 2 marks d i Define the term Heat of atomization of a compound. 1mark ii Use the following information to answer the questions that follow. C s O2 g CO2 g H 393kJmol 1 H2 g O2 g H2O g H 285kJmol 1 C2H5OH l 3O2 g 2CO2 g 3H2O g H 1370kJmol 1 Calculate the heat of formation of ethanol. 2marks 3. Study the table below and answer the questions that follow. The letter do not represent the actual symbols of the elements Element A B C D E F G H Atomic number 11 12 13 14 15 16 17 18 Boiling point 0c 890 1110 2470 2360 280 445 -34.2 -186 Formula of Oxide BO E2O5 G2O Boiling point of oxide of 0c 1193 3075 2045 1728 563 -72 -91 a Complete the table to show the formulae of the oxides of A, C, D, and F. 2marks b State the period to which the element above belong to. |
Study the table below and answer the questions that follow. The letter do not represent the actual symbols of the elements Element A B C D E F G H Atomic number 11 12 13 14 15 16 17 18 Boiling point 0c 890 1110 2470 2360 280 445 -34.2 -186 Formula of Oxide BO E2O5 G2O Boiling point of oxide of 0c 1193 3075 2045 1728 563 -72 -91 a Complete the table to show the formulae of the oxides of A, C, D, and F. 2marks b State the period to which the element above belong to. 1mark Lead II nitrate Heat Boiling tube Liquid B Gas A Warm water Icewww.freekcsepastpapers.comPage 257 c Select an oxide that reacts with both dilute hydrochloric acid and potassium hydroxide solution. 1mark d Write an equation for the reaction between the oxide of A and water. 1mark e Explain the difference in boiling point of the chlorides of B and C. 2marks f Write the formula of the compound formed between E and G. 1mark g Explain the difference in the atomic radii of elements D and H. 2marks 4. The flow diagram below is for the extraction of zinc. A Name the chief ore from which zinc is extracted. 1mark b Describe how froth floatation is carried out 2marks c Name the process taking place at I and II 2marks d Explain how zinc liquid is changes to zinc granules. 1mk e Identify the reagent used at stage II. 1 mark f Name two major environmental pollutants likely to be released into the atmosphere 1 mark g Zinc sulphide and sulphuric acid react according to the following equation: ZnS S H2SO4 aq ZnSO4 aq H2S g 2.91g of zinc sulphide reacted with 100cm of 0.2M sulphuric acid. Determine the limiting reagent in this reaction. Zn 65.0, S 32.0 . |
1mk b i Draw a diagram to show how an aluminium spoon can be electroplated with copper. 2 marks ii In the experiment to electroplate aluminium spoon, 0.2 amperes were passed through the solution for 1,930 seconds. The mass of the aluminium spoon increased from 6.35 to 6.478 g. Find the charge on a copper ion. 1 Faraday 96,500 coulombs, Cu 64 . 3 marks Step I Step II Step III Step IV Step V MnO2www.freekcsepastpapers.comPage 259 c The diagram below represents a mercury cell that can be used in the industrial manufacture of sodium hydroxide. Study it and answer the questions that follow: I Name: i Raw material introduced at 2. Mark ii Another substance that can be used in the cell instead of graphite. Mark II Identify the by-product that comes out at I. 1 mark III Write an equation for the reaction:- i That occurred at the anode. 1 mark ii In which sodium hydroxide was produced. 1 mark IV Give two reasons why mercury is recycled. 1 mark 7. A Petrol is a mixture of hydrocarbons used as a fuel and is obtained from crude oil by fractional distillation. I Define the term fractional distillation 1mk ii Name two gases that pollute the atmosphere as a result of burning in internal combustion engines. 1mk iii Tetraethyl lead is an anti-knock additive that is added to petrol. This petrol additive is however being phased out. Give a reason to this. 1mk iv CF2Cl2 is present in aerosols. Explain how it is a hazard to the atmosphere and give its systematic name. 1 mark v One of the hydrocarbons present in petrol is 3,3-dimethylpentane. C7H16 11O2 7CO2 8H2O, H -4800Kj I. What mass of carbon IV oxide would be produced when 5g of C7H16 were burned? C 12, H 1, O 16 2mks II. |
C7H16 11O2 7CO2 8H2O, H -4800Kj I. What mass of carbon IV oxide would be produced when 5g of C7H16 were burned? C 12, H 1, O 16 2mks II. Draw the structural formula of 3,3-dimethylpentane. 1mk b Perspex is a synthetic polymer formed from the monomer below. I Draw a polymer with three repeat units. 1 mark ii A sample of Perspex has a mass of 100,000g. Calculate the number of monomers in the Perspex. 1 mark 1www.freekcsepastpapers.comPage 260 c Sodium hexandecanoate sodium palmate commonly known as Imperial Leather soap is manufactured by hydrolysis of palmitic acid using sodium hydroxide as shown. Write the formula of the Imperial Leather soap and the product V. 2 marks Imperial Leather soap Product V Product V 3NaOH Imperial Leather soapwww.freekcsepastpapers.comPage 261 GATUNDU SOUTH JOINT EXAMINATIONS, 2023 Kenya Certificate of Secondary Education 233 3 CHEMISTRY PAPER 3 CONFIDENTIAL Requirements for each candidate 1. 150 cm3 of solution A 2. 200 cm3 of solution B 3. 60 cm3 of solution X 4. 150 cm3 of solution Z 5. Pipette 6. Burette 7. Thermometer 8. Stop watch 9. 2 conical flasks 10. 1 boiling tube 11. 7 test tubes 12. 2 filter paper and a filter funnel 13. Clean spatula 14. 10 ml measuring cylinder 15. 50 ml 100 ml measuring cylinder 16. Solid Q 1g Na2 CO3 : PbCO3 1:2 17. Solid M. Crushed paracetamol.1 tablet per candidate ACCESS i 2M HNO3 ii 2M HCl iii 2M NH3 iv Acidified KMnO4 v Acidified K2Cr2O7 vi Bromine vii Source of heat viii Tripod stand ix Wire gauze NOTES a. |
Solid Q 1g Na2 CO3 : PbCO3 1:2 17. Solid M. Crushed paracetamol.1 tablet per candidate ACCESS i 2M HNO3 ii 2M HCl iii 2M NH3 iv Acidified KMnO4 v Acidified K2Cr2O7 vi Bromine vii Source of heat viii Tripod stand ix Wire gauze NOTES a. Solution B 0.04 M acidified KMNO4 b. Solution A Ferrous ammonium sulphate Fe SO4 NH4 2 SO4 X H2O made by dissolving 8.5 g in 50 cm3 of 2M H2SO4 making it to 250 cm3 c. Solution X which is prepared by dissolving 75.6 g of glucose in about 500 cm3 of distilled water, then making it up to the liter. D. Solution Z, 2 M Sulphuric vi acid. Www.freekcsepastpapers.comPage 262 GATUNDU SOUTH JOINT EXAMINATIONS, 2023 Kenya Certificate of Secondary Education 233 3 CHEMISTRY Paper 3 PRACTICAL Time: 2 Hours Instructions to candidates Answer all the questions You are NOT allowed to start working with the apparatus for the first 15 minutes of the 2 Hours allowed for this paper. This time is to enable you to read the question paper and make sure you have all the chemicals and apparatus that you may need. Mathematical tables and silent electronic calculators may be used. All working must clearly be shown where necessary. 1. A You are provided with; i Solution A Ferrous ammonium sulphate FeSO4. NH4 2SO4. XH2O containing 8.5g in 250cm3 of solution ii Solution B 0.04 M acidified potassium manganite VII You are required to determine the value of X in FeSO4. NH4 2SO4. XH2O Procedure I Fill the burette with solution B. Pipette 25.0cm3 of solution A into a clean conical flask and titrate until the solution turns pink. Record your results in table I below. |
1 mark ii The concentration of solution A in moles per litre 1 marks iii The concentration of solution A in grams per litre 1 marks iv The relative formula mass of iron II salt 1 marks v The value of X in the formula FeSO4. NH4 2 SO4.XH2O Fe 56, N 14, S 32, O 16 1 mark b You are provided with 2.0 M sulphuric vi acid labeled as solution Z 0.42 M glucose solution labeled as solution X 0.04 M potassium manganate vii labeled as solution B You are required to determine the rate of reaction between aqueous glucose solution and acidified potassium manganate vii at different temperatures. Procedure i Using the 10 cm3 measuring cylinder, place 10 cm3 of solution B into the conical flask ii Rinse the 10 cm3 measuring cylinder and use it to measure 10 cm3 of solution of solution X. Keep it for step belowwww.freekcsepastpapers.comPage 263 iii Using the 100cm3 or the 50 cm3 measuring cylinder, measure 25 cm3 of solution Z and add it into the conical flask, containing solution B, Heat the mixture to slightly above 65 0c and then remove it from the heat source. Iv Allow the mixture in step 3 to cool to 650c, then add the 10 cm3 of solution X and immediately start the stop watch. V Stir the mixture and note the time taken for the colour of the mixture to change from purple to colourless. Record the time taken in the table below. Vi Rinse the conical flask and the 10 cm3 measuring cylinder and repeat the procedure at temperatures of 600 c, 550c , 500c,and 450c respectively. Record the time taken in the table below in each case. Vii Complete the table by calculating the reciprocal of time 1 t Temperature of the solutions 0c 65 60 55 50 45 Time taken for the purple colour to disappear s 1 t sec- 5mks I. Plot a graph of 1 t y axis against the temperature at the point when the solution becomes colourless 3mks II . |
Record the time taken in the table below in each case. Vii Complete the table by calculating the reciprocal of time 1 t Temperature of the solutions 0c 65 60 55 50 45 Time taken for the purple colour to disappear s 1 t sec- 5mks I. Plot a graph of 1 t y axis against the temperature at the point when the solution becomes colourless 3mks II . From the graph a Determine the time that the reaction would take if the temperature at which the solution becomes colourless is 52.50c 2mks b Determine the rate of reaction if the temperature at which the solution becomes colourless is 470c 1mk c Explain the shape of the graph 1mk 2. You are provided with solid Q Carry out the following tests and record your observations and inferences in the spaces provided, a Add about 15 cm3 of distilled water to solid Q and shake. Filter and retain both the filtrate and the residue. I To about 2 cm3 of the filtrate add ammonia solution drop wise until in excess Observations Inferences 1 mark 1 mark ii To about 2 cm3 of the filtrate add a few drops of dilute hydrochloric acid. Observations Inferences 1 mark 1 mark b i Put the residue in a test tube and add about 10cm3 of dilute nitric v acid and wait for about five minutes To 2 cm3 of the solution add 2 to 3 drops of barium nitrate Observations Inferences 1 mark 1 mark ii To 2 cm3 of the solution add ammonia solution drop wise until in excess Observations Inferences 1 mark 1 mark iii .To 2 cm3 of the solution add 2 to 3 drops of potassium iodide solution Observations Inferences 1 mark 1 mark www.freekcsepastpapers.comPage 264 3. You are provided with organic solid M, Carry out the tests below. |
KNEC Mathematical tables and silent non-programmable electronic calculators may be used. 3. All working MUST be clearly shown where necessary 1. A Explain the condensation process using the kinetic theory of matter. 1mk b Name one chemistry laboratory apparatus that can be used to measure accurate volume of a solution 1mk 2. Study the flow chart below and answer the questions that follow: a Identify i Q 1 2 mk ii R 1 2 mk b State two uses of Polyvinylchloride 1mk 3. Naphthalene is soluble in ether but not in water and has a melting point of 800C.You are provided with a mixture of powdered naphthalene, Sodium Chloride and Zinc Carbonate. Describe briefly how Naphthalene can be obtained from the mixture. 3mk 4. A Name a suitable solvent for extracting an indicator from flowers. 1mk b Give a reason why the solvent named in a above is used 1mk 5. Using the elements Chlorine, Calcium and Phosphorus, a Select Elements that will form an Oxide whose aqueous solution has a PH of Less than 7. 1mk b Write an Equation for the reaction between Calcium Oxide and dilute Hydrochloric Acid. 1mk c Give one use of Calcium oxide. 1mk 6. When steam was passed over heated charcoal as shown below, Hydrogen and carbon II Oxide were formed. Www.freekcsepastpapers.comPage 276 a Write the equation for the reaction that takes place 1mk b Name one common use of carbon II Oxide and Hydrogen gas. 1mk 7. A State Grahams Law of Diffusion. 1mks b Determine how long it would take for a given volume of ammonia gas to diffuse through a porous plug , If the same volume of hydrogen chloride takes 48 seconds to diffuse under the same conditions. 3mks 8. In an experiment it was found out that 0.28g of iron powder reacted with 0.53g of chlorine. Use this information to write a balanced equation to represent the reaction. Fe 56, Cl 35.5 . 3mks 9. |
Use this information to write a balanced equation to represent the reaction. Fe 56, Cl 35.5 . 3mks 9. A What is meant by atomic number? 1mk b An element P has a mass number of 35 and atomic number 17.Draw a diagram showing the Composition of electrons and the composition of the nucleus of its atom. 2mks 10. The table below shows properties of some elements P, Q, R and S which belong to the same period of the periodic table. The letters are not the actual symbols of the elements. Element P Q R S M.P 0C 1410 98 -101 660 Atomic Radius 0.117 0.186 0.099 0.143 Electrical conductivity P00v Good Non conductor Good a Arrange the elements in the order they would appear in the period. Give reasons. 2mks b Select the metallic element which is the better conductor of electricity. Give a reason. 2mks 11. Distinguish between polar substances and non-polar substances 1mk 12. Starting with copper describe how a pure sample of copper II carbonate can be prepared. 3mks 13. Study the setup below and answer the questions that follow: a Write an equation for the reaction between ammonia and copper II Oxide 1mk b During the experiment the colour of the contents in the water trough changed .State the colour observed and give an explanation. 2mks 14. A Define the molar heat of displacement 1mk b The following ionic equation represents the reaction between metal Z and aqueous Y2 Z s Y2 aq Z2 aq Y s H -VE Draw an energy level diagram to represent the reaction 2mks 15. A Why is graphite preferred for use as a non-greasy lubricant 2mk b Brine is electrolysed using graphite as electrodes .State the products formed at i Anode 1mk ii Cathode 1mk 16. A Sulphur IV Oxide is bubbled through acidified Potassium Manganate VII . State and Explain the observation made. 2mks b What is meant by vulcanisation? |
1mk 21. A State the Le Chatelier s principle 1mk b Carbon II oxide gas reacts with steam according to the equation. CO g H20 g H2 g CO 2 g What would be the effect of increasing pressure of the system at equilibrium .Explain 2mks 22. Given the following half cell equations; P2 aq 2e- P S E -2.37V Q2 aq 2e- S E -0.76V a Write an equation for the cell reaction. 1mk b Calculate the E value for the cell 1mk c Write the cell representation for the electrochemical cell formed. 1mk 23. A hydrated salt has the following composition by mass. Iron 20.2 , oxygen 23.0 , Sulphur -11.5 and water 45.3 . Determine the empirical formula of the salt. Fe 56, S 32, O 16, H 1 3 mks 24. Give the systematic names of the following compounds 3mks a CH3 CH CH3 CH2 CH3 b CH3 CH2CH2 CH Br CH2 OH c HOCH2 CH2 CH2OH 25. Using a well labelled diagram, illustrate how an iron bungle can be electroplated using silver 3mks 26. Study the sequence of reactions below and answer the questions that follow; Mg Air Nitrogen Magnesium nitride Step I Step II Step III Ammonia. A Name the process in step I 1mk b Name the reagent that can be used in step III. 1mk www.freekcsepastpapers.comPage 278 c Write a balancing Equation for step II 1mk 27. When an aqueous solution of compound W was mixed with a few drops of Bromine water, the colour of the mixture remained yellow. When another portion of W was reacted with acidified potassium dichromate VI , the colour of the mixture changed from orange to green. A What conclusion can be made from the use of i Bromine water? |
All working MUST be clearly shown where necessary 1. Study the figure below and answer the questions that follow a Write the formula of the organic compounds P and S 2mks b Name the types of reaction, the reagents and conditions for the reactions in the following steps 4mrks Reaction Reagent condition Step I Step II c Name the reagent R 1mrk d Draw the structural formula of T and give its name i Structural Formula 1Mk ii Name 1mk e If the relative molecular mass of U is 42000, determine the value of n C 12, H 1 2mrks f State the reasons why C2H4 burns with more smoky flame than C2H6 1mrk 2. The heat of solution of magnesium chloride is 1278 kJ Mol. Given that the lattice energy of magnesium chloride is -3933kJ Mole and hydration energy of magnesium is -1891kJ Mol a Draw an energy level diagram to show this information 2mrks b Calculate the hydration energy of chloride ions 2mrks c The enthalpies of combustions of methane, carbon and hydrogen are -886.7, -393.5 and -285.7 kJ Mol respectively. Use the information given to calculate molar heat of formation of methane 2mrks d State two measures taken to reduce pollution by vehicles 2mrks www.freekcsepastpapers.comPage 280 3 In an experiment to study the reactions between German silver an alloy of Nickel, Zinc and Copper and excess sulphuric VI acid, the data below was recorded. It showed the volume of gas collected after every one minute. Use it to answer the questions that follow. |
An excess of copper carbonate is added to 50.0cm3 of 2M sulphuric VI acid in a beaker and the mixture warmed until no further reaction takes place. The warm mixture is then filtered and the filtrate evaporated until the volume reduced to 20.0cm3. The mixture is allowed to cool and the crystals formed dried and weighed. A Write the ionic equation for the reaction 1mrk b Give reason for adding excess copper carbonate 1mrk c Give reasons for warming the mixture 1mark d How does one determine the end of the reaction 1mrk e Why is it necessary to filter the reaction mixture after the end of reaction 1mrk f It is advisable not to evaporate the filtrate to dryness. Give two reasons 2mrks g Determine the mass of anhydrous copper ii sulphate formed 3mrks CU 64, S 32, O 16, H 1 h Give reasons as to why crystals of Lead II sulphate are not prepared using lead carbonate and Sulphuric VI acid as outlined in the experiment above 2mrks 5. The diagram below represents a mercury cell chlor-alkali process that can be used in the industrial manufacture of sodium hydroxide. Study it and answer the questions that follow. Www.freekcsepastpapers.comPage 281 a i Name the raw materials introduced at 1 and 2. 2 marks ii Identify a substance that can be used as anode. 1 mark iii Write equations for the reactions taking place at: Cathode 2 marks Decomposer 1 mark iv Give two reasons why mercury is recycled. 2 marks v How is the aqueous sodium hydroxide purified? 1 mark vi State one use of sodium hydroxide. 1 mark b If a factory produces 1000 kg of sodium hydroxide in every 24 hours, calculate the required current per day. H 1.0, Na 23.0, O 16.0 2 marks 6. |
1 mark vi State one use of sodium hydroxide. 1 mark b If a factory produces 1000 kg of sodium hydroxide in every 24 hours, calculate the required current per day. H 1.0, Na 23.0, O 16.0 2 marks 6. Study the following diagram below and use it to answer the questions that follow:- a Identify ions present in solid R 1mrk b Identify Solid V 1mk Solution S- 1 mk Solution T- 1mk c Write an equation leading to the formation of substance Z 1mrk d What is the identity of? Brown gas- 1mk Colorless gas- 1mk Yellow solid 1mk e What name is given to the reaction in step 2? 1mrk f State and explain the observation that would be made if sodium carbonate solution was added to solution S 1mk www.freekcsepastpapers.comPage 282 7. The table below represents part of the periodic table. The letters do not represent the actual symbols of the elements. Study it and answer the questions that follow: S P Z T D Q C X J R a To which family do element P, Q and R belong? 1mrk b Write the electronic arrangements of stable ions of D and C 2mrks c Compare melting point of chlorides of Z and T 2mrks d Select the most reactive metallic element 1mrk e Give one use of element Q 1mrk f Compare the atomic radius of element Z and J 2mrks g Element B forms an ion B3- with electron arrangement of 2.8.8. Place it on the periodic grid above 1mrks h Write the formula of the compound formed when elements X and D react 1mk i Explain the trend of reactivity of element Z, C and J 1mk www.freekcsepastpapers.comPage 283 KIGUMO CLUSTER EXAMINATION, 2023 Kenya Certificate of Secondary Education KCSE 233 3 CHEMISTRY PAPER 3 CONFIDENTIAL Requirements to Candidates In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require. |
Study it and answer the questions that follow: S P Z T D Q C X J R a To which family do element P, Q and R belong? 1mrk b Write the electronic arrangements of stable ions of D and C 2mrks c Compare melting point of chlorides of Z and T 2mrks d Select the most reactive metallic element 1mrk e Give one use of element Q 1mrk f Compare the atomic radius of element Z and J 2mrks g Element B forms an ion B3- with electron arrangement of 2.8.8. Place it on the periodic grid above 1mrks h Write the formula of the compound formed when elements X and D react 1mk i Explain the trend of reactivity of element Z, C and J 1mk www.freekcsepastpapers.comPage 283 KIGUMO CLUSTER EXAMINATION, 2023 Kenya Certificate of Secondary Education KCSE 233 3 CHEMISTRY PAPER 3 CONFIDENTIAL Requirements to Candidates In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require. 1. Solid A 4.8 g of oxalic acid in a boiling tube 2. 100cm3 solution B 0.2M NaOH 3. Thermometer -10 C 110 C 4. One 50ml burette 5. Filter funnel 6. Pipette and pipette filler 7. One label 8. 250ml volumetric flask 9. Two 250ml conical flasks 10. About 300cm3 of distilled water 11. Bunsen burner 12. 0.5g of solid F maleic acid 13. 0.5g of solid V iron iii sulphate 14. 6 test-tubes in a rack 15. Boiling tubes 2 16. Test tube holder Access to the following; 1. Phenolphthalein indicator supplied with a dropper 2. 2M NaOH supplied with a dropper 3. Dilute nitric V acid supplied with a dropper 4. 0.5M Pb NO3 2 supplied with a dropper 5. 0.5g NaHCO3 supplied with a dropper 6. |
Dilute nitric V acid supplied with a dropper 4. 0.5M Pb NO3 2 supplied with a dropper 5. 0.5g NaHCO3 supplied with a dropper 6. Acidified K2Cr2O7 supplied with a dropper 7. Acidified KMnO4 supplied with a dropper 8. Bromine water NB Each of the solutions in Bottle should be supplied with a dropper. Preparations Solution B is prepared by dissolving 8.0g of NaOH pellets in 600cm3 of distilled H2O then making it to one litre of solution Acidified potassium permanganate is prepared by dissolving 3.16g of solid KMnO4 in 400cm3 of 1M H2SO4 acid and making it to one litre of solution. Www.freekcsepastpapers.comPage 284 KIGUMO CLUSTER EXAMINATION, 2023 Kenya Certificate of Secondary Education KCSE 233 3 CHEMISTRY Practical Paper 3 Time: 2 Hours Kenya Certificate of Secondary Education a Answer ALL the questions b KNEC Mathematical tables and electronic calculators may be used for calculations c All working MUST be clearly shown where necessary 1. You are provided with; - 4.8g of solid A which is a hydrated acid with formula H2C2O4.nH2O - Solution B, a 0.2M sodium hydroxide solution. You are required to determine: Solubility of solid A Procedure 1 Fill the burette with distilled water Place solid A in the boiling tube. Transfer 4cm3 of distilled water from the burette into the boiling tube containing solid A. Heat the mixture while stirring with the thermometer to a temperature of 75 C. Allow the solution to cool while stirring with a thermometer. Record the temperature at which the crystals start to form in the table below Add a further 2cm3 of distilled water from the burette to the mixture Repeat procedure iv and v above and record the crystallization temperature. Complete the table below by adding the volumes of distilled water as indicated. |
Allow the solution to cool while stirring with a thermometer. Record the temperature at which the crystals start to form in the table below Add a further 2cm3 of distilled water from the burette to the mixture Repeat procedure iv and v above and record the crystallization temperature. Complete the table below by adding the volumes of distilled water as indicated. PRESERVE THE CONTENTS Volume of distilled water cm3 Crystallization temperature Solubility of solid A in g 100g of water 4.0 6.0 8.0 10.0 12.0 14.0 6marks a On the grid provided, plot a graph of solubility of solid A y axis against crystallization temperature. 3 marks b From the graph determine; i The solubility of solid A at 80 C 1 mark ii The temperature at which 34g of A dissolves in 50g of water 1 mark iii Describe the trend of the graph 1 Mk Procedure II Transfer the contents of the boiling tube in procedure I to a clean 250ml volumetric flask. Add distilled water to the mark Label the resulting solution as C Fill the burette with solution C Pipette 25cm3 of solution B into a clean conical flask. Add three drops of phenolphthalein indicator Titrate C against B to an accurate end point. Www.freekcsepastpapers.comPage 285 Record your results in table II below Table II 4 mks Calculate; a Average volume of C used 1mark b Moles of solution B used 1mark c Moles of solution C given that 2 moles of B react with 1 mole of C. 1 mark d Concentration of solution C in moles per litre 1 mark 2. A You are provided with: - Solid V, which could be iron III sulphate - 1 M nitric acid - 1 M sodium hydroxide - Source of heat - Distilled water - 0.1 M Lead II nitrate solution i From the reagents provided, describe three tests that may be carried out consecutively to confirm if solid V is iron III sulphate. Write the tests and expected observations in the spaces provided. |
1 mark d Concentration of solution C in moles per litre 1 mark 2. A You are provided with: - Solid V, which could be iron III sulphate - 1 M nitric acid - 1 M sodium hydroxide - Source of heat - Distilled water - 0.1 M Lead II nitrate solution i From the reagents provided, describe three tests that may be carried out consecutively to confirm if solid V is iron III sulphate. Write the tests and expected observations in the spaces provided. Test 1 Expected Observations 1 mark 1 mark Test 2 Expected Observations 1 mark 1 mark Test 3 Expected Observations 1 mark 1 mark ii Carry out the tests described in a above using solid V and record the observations and inferences in the spaces provided. Test 1 Observations Inferences 1 mark 1 mark Test 2 Observations Inferences 1 mark 1 mark Test 3 Observations Inferences 1 mark 1 mark I II III Final burette reading in cm3 Initial burette reading in cm3 Volume of solution C used in cm3www.freekcsepastpapers.comPage 286 3. You are provided with solid F carry out the tests below write your observations and inferences in the spaces provided a. Place the half of solid F in a boiling tube and add 12cm3 of distilled water divide the resulting solution into five portions b. To the first portion add acidified potassium manganate VII and warm Observations Inference 1 marks 1 marks c. To the second portion add acidified potassium dichromate VI solution and warm Observations Inference 1 marks 1 marks d. To the third portion add NaHCO3 Observations Inference 1 marks 1 marks e. Test the forth portion add bromine water Observations Inference 1 marks 1 marks www.freekcsepastpapers.comPage 294 BOKAKE JOINT EXAMINATIONS, 2023 Kenya Certificate of Secondary Education 233 1 CHEMISTRY Paper 1 Theory TIME: 2 HOURS INSTRUCTIONS TO CANDIDATES 1. All working must be clearly shown where necessary. 2. |
Na 23, O 16, H 1, S 32 3mks 6. Describe how you can extract oil from ground nuts? 3marks 7. Passing a small quantity of carbon iv oxide through calcium hydroxide, forms a white precipitate which dissolves when excess carbon IV oxide is bubbled through. A Name the white precipitate. Mk b Explain using a chemical equation why the white precipitate dissolves in excess carbon IV oxide. 1 mks c What will happen when solution in b above is boiled? 1mk 8. The scheme below represents some reactions starting with a white solid A. a Identify solid A 1mk b Write an equation for the reaction between solid B and 2M sulphuric VI acid. 1mk c Write ionic equation for the formation of colourless solution Z. 1mk 9. Some reaction of metals P, Q, R and S are given below. Metal Reaction with water Reaction with dilute hydrochloric acid P A few bubbles form slowly in water Vigorous reaction. Gas is given off Q Vigorous reaction , metal melts gas given off Explosive reaction Should not be attempted R No reaction No reaction S Does not react with cold water. Hot metal reacts with steam Steady fizzing a Arrange the metals in order of the reactivity starting with the least reactive. 1mk b Write a chemical equation for the reaction between metal Q and water 1mk c Which of the metals could be copper? Explain. 1mk 10. The diagram below shows the laboratory preparation of hydrochloric acid. A State the condition necessary for the reaction to occur. 1mk b Write a chemical equation for the reaction between sodium chloride and concentrated sulphuric VI acid. 1mk c Give one reason why an inverted funnel is used instead of delivery tube. 1mk 11. Use the reaction scheme below to answer the questions that follow. A Draw the structure of alkanol X. 1mk b Name process Y. 1mk www.freekcsepastpapers.comPage 296 c Write the molecular formula of the 5th member in which propene belong. 1mk 12. |
1mk b Name process Y. 1mk www.freekcsepastpapers.comPage 296 c Write the molecular formula of the 5th member in which propene belong. 1mk 12. Study the reaction below and answer the questions that follow NH3 g H2O l NH4 aq OH- aq a Define the term acid 1mk b Identify an acid in the above reaction 1mk c Explain your answers in b above 1mk 13. Define; a Solubility 1mk b The solubility of Iron II Sulphate crystals is 22oC is 15.65g per 100g of water. Calculate the mass of iron II sulphate crystals in 45g of saturated solution at the same temperature. 2mks 14. In an attempt to prepare a gas, Njeri added concentrated hydrochloric acid to Potassium manganate. The products were then passed through two wash bottles containing water and concentrated sulphuric acid a Name the gas prepared 1mk b Name the purpose of wash bottle: i Containing water? 1mk ii Containing concentrated sulphuric acid? 1mk 15. A fixed mass of gas occupies 200 cm3 at a temperature of 230c and a pressure of 740 mm Hg. Calculate the volume of the gas at -250c and 790 mm Hg pressure. 2mks 16. Study the table below and answer the questions that follow a Calculate the enthalpy change for the following reaction 2mks C2H4 g Br2 g C2H4Br2 g b Name the type of reaction that took place in a above 1 mark 17. Study the diagram below and answer the questions that follow: a What do H1 and H2 represent? H1 1mkwww.freekcsepastpapers.comPage 297 H2 1mk b Write an expression to show the relationship between H1, H2 and H3. 1mk 18. |
Study the diagram below and answer the questions that follow: a What do H1 and H2 represent? H1 1mkwww.freekcsepastpapers.comPage 297 H2 1mk b Write an expression to show the relationship between H1, H2 and H3. 1mk 18. Nitrogen and hydrogen react reversibly according to the equation:- N2 g 3H2 g 2NH3 g ; H -92kjmol-1 How would the yield of ammonia be affected by: i A increase in temperature. 2mks ii An increase in pressure. 1mk 19. Study the information in the table below and answer the questions that follow: Element Atomic radius nm Ionic radius nm W 0.114 0.195 X 0.072 0.136 Y 0.133 0.216 Z 0.099 0.181 a Would these form part of a metallic or a non-metallic group? Explain 1 mks b Suggest an element in the table above likely to be the most reactive. Explain 1 mks 20. Give the IUPAC names of the following compounds: 3mks i CH3COOCH2CH3 ii CH3CH2COOH iii 21. The structure below represents a cleansing agent. A State the type of cleansing agent represented above 1mk b State one advantage and one disadvantage of using the above cleansing agent. 2mks 22. The grid below represents part of the periodic table. Study it and answer the questions that follow: i Identify the element that gains electrons most readily 1mk ii Which of the metal is most reactive? Explain 1mk iii What name is given to the family of elements to which elements X and T belong? 1mk 23. 3.52g of Carbon IV Oxide and 1.40g of water are produced when a mass of a hydrocarbon is completely burnt in oxygen. Determine the empirical formula of the hydrocarbon; H 1 , C 12, O 16 3mks 24. A Hydrogen can reduce coppers Oxide but not aluminium oxide. |
3.52g of Carbon IV Oxide and 1.40g of water are produced when a mass of a hydrocarbon is completely burnt in oxygen. Determine the empirical formula of the hydrocarbon; H 1 , C 12, O 16 3mks 24. A Hydrogen can reduce coppers Oxide but not aluminium oxide. Explain 1mk b When water reacts with potassium metal the hydrogen produced ignites explosively on the surface of water. I What causes this ignition? 1mk ii Write an equation to show how this ignition occurs 1mkwww.freekcsepastpapers.comPage 298 25. The diagram below shows the extraction of sulphur by Frasch process. State the uses of pipes A, B and C. 3mks 26. The set-up below was used to prepare dry sample of hydrogen sulphide gas a i Complete the diagram to show how the gas was collected 2mks ii Identify the following:- I. Solid H mk II. Solid I mk 27. Define the following terms: a Malleability. 1mk b Ductility. 1mk c Give an example of element with the above properties. 1mkwww.freekcsepastpapers.comPage 299 BOKAKE JOINT EXAMINATIONS, 2023 233 2 CHEMISTRY PAPER 2 THEORY 2 HOURS Instructions to candidates a Answer all the questions. B Non-programmable silent electronic calculators and KNEC mathematical tables may be used. C All working must be clearly shown where necessary. 1. The set up below shows the reagents that can form hydrogen gas in a laboratory. A Complete the diagram to show how a dry sample of hydrogen gas can be collected. 3 marks b Write the chemical equation for above reaction. 1 mark c Why is it not advisable to use calcium in this method to prepare hydrogen? 1 mark d Why is it advisable to discard the first jar of the gas collected? 1 mark e The set-up below was used to investigate some of the properties of hydrogen gas. I State the observation made in the combustion tube. 1 mark ii Write down the equation leading to formation of liquid L. |
1 mark e The set-up below was used to investigate some of the properties of hydrogen gas. I State the observation made in the combustion tube. 1 mark ii Write down the equation leading to formation of liquid L. 1 mark iii What property of hydrogen is being investigated? 1 mark iv Why is potassium oxide not used to investigate this property of hydrogen gas? 1 mark v Hydrogen gas is used in hydrogenation of oils. What do you understand by the term? Hydrogenation? 1 mark vi Give any two other industrial uses of hydrogen gas. 2 marks www.freekcsepastpapers.comPage 300 2. The chart below represents the main steps in the large-scale manufacture of sodium carbonate. A Name substances A and B. 2 marks b Write down the chemical equation leading to formation of C. 1 mark c A stream of cold water is made to circulate around chamber X. What does this suggest about the reaction taking place. 1 mark d Name the process that takes place in chamber Y. 1 mark e State any two by-products recycled in the process. 2 marks f Give any two uses of sodium carbonate. 1 mark g In an experiment, wood charcoal was mixed with concentrated sulphuric VI acid in a test-tube. The mixture was then placed over a Bunsen-burner flame for some time. I Write down the chemical equation of the reaction that takes place. 1 mark ii State the property of concentrated sulphuric VI acid investigated in i above. 1 mark 3. A Ethyne gas can be prepared in the laboratory by action of water on a certain compound M i Name compound M . 1 mark ii Write an equation for the reaction taking place between compound M and water. 1mark iii Name the homologous series in which ethyne belongs. 1mark iv State one commercial use of ethyne. 1 mark b The scheme below represents some reactions of ethyne. Study it and answer the questions that follow. I Name compound P and draw its structural formula. |
1 mark b The scheme below represents some reactions of ethyne. Study it and answer the questions that follow. I Name compound P and draw its structural formula. 2 marks ii Identify the reagents used in: I Process R 1 mark II Step I 1 mark iii Draw the repeating unit in polymer T. 1 mark iv Name polymer T ... 1 mark v Give one use of polymer T 1 mark www.freekcsepastpapers.comPage 301 4. In the preparation of Copper carbonate, copper was burnt in air and the product collected. Dilute sulphuric acid was added and the mixture filtered and cooled. Sodium carbonate solution was added to the filtrate and the content filtered. The residue was washed and dried to give a green powder. A Give the chemical name of the product formed when Copper burns in air 1mk b Write a chemical equation that leads to the formation of the green powder. 1mk c i Name filtrate collected after sodium carbonate was added 1mk ii Name the green powder. 1mk d Write chemical equation for the reaction between product in a and acid. 1mk e Write an ionic equation to show the formation of the green powder 1mk f Write an equation to show what happened when green powder is strongly heated. 1mk g Using a diagram, describe how a salt can be obtained from the filtrate in c i above 3mks 5. The grid below shows a section of the periodic table. The letters do not represent the actual symbols of the elements. K L M N P Q R S T V W a Name the family to which element P belongs. 1mark b Which two elements will form carbonates that do not decompose on heating. 1 mark c With a reason, identify an element in period three with the largest atomic radius. |
K L M N P Q R S T V W a Name the family to which element P belongs. 1mark b Which two elements will form carbonates that do not decompose on heating. 1 mark c With a reason, identify an element in period three with the largest atomic radius. 2marks d Write the formula of the compound formed between L and M 1 mark e State two uses of element R and for each use, state property of element R that makes it possible for the use i Use 1mark Property mark ii Use 1 mark Property mark f Using dots and cross x , show bonding in the compound formed between R and oxygen. 2 marks g In terms of structure and bonding, explain why the boiling point of the oxide of L is higher than that of N. 2 marks h Calculate the volume of the gas produced when 1.95g of element W reacts with water W 39, Molar gas volume at S.T.P 24,000cm3 2 marks 6. A The diagram below represents the extraction of Sulphur by the Frasch process. I Identify and state the use of the substances that pass through tubes A and C. 2 marks ii Rhombic and monoclinic are allotropes of Sulphur. They are inter convertible as shown below Rhombic Monoclinic I. What does the temperature 96 C represent? 1 mark II. State the difference in crystalline appearances between rhombic and monoclinic crystals. L mark b The following scheme represents the steps followed in the contact process, study it and answer the questions which follow. Rhombicwww.freekcsepastpapers.comPage 302 i Name solid A. 1 mark ii Name two impurities removed by the purifier. 1 mark iii Why is it necessary to remove impurities? 1 mark iv Write chemical equations for the reactions which occur in the; Catalytic chamber 1 mark Diluter 1 mark v State the optimum temperature used in the catalytic chamber. 1 mark vi Why is sulphur VI oxide gas not dissolved in water directly. 1mark 7. |
Molar volume at s.t.p 22.4dm3, zn 65 2 marks e On the same axis, draw a sketch of the graph that would be obtained if the zinc granules are reacted with 1.0M hydrochloric acid. 1 mark www.freekcsepastpapers.comPage 303 BOKAKE JOINT EXAMINATIONS, 2023 Kenya Certificate of Secondary Education 233 3 CHEMISTRY Practical 3 Time 2 hours 1. You are provided with the following o 4cm of magnesium ribbon o 2M hydrochloric acid solution A You are require to determine the rate of reaction of magnesium with hydrochloric acid PROCEDURE Take four 100cm3 plastic beaker and label them 1,2,3,4 To the first beaker, place 10cm3 of 2M hydrochloric acid. To the second beaker place 8cm3 of acid and 2cm3 of distilled water. To the third beaker place 6cm3 of acid and 2cm3 of distilled water. To the forth beaker place 4cm3 of acid and 6cm3 of distilled water. Cut the magnesium ribbon into 4 parts of 1cm each Place a piece of 1cm magnesium ribbon into the first beaker and start the stop watch Record the time taken for the magnesium ribbon to disappear completely. Record it in the table below. Repeat this procedure with beaker 2, 3 and 4 to complete the table. 4mks Beaker 1 2 3 4 Volume of acid cm3 10 8 6 4 Volume of water cm3 0 2 4 6 Time second a Plot a graph of volume of acid cm3 against time sec in the graph provided. 3mks b From the graph determine; i Time taken for magnesium to disappear completely at 5cm3 1mk ii Volume of the acid in which magnesium takes 100 seconds to disappear completely 1mk c The rate of reaction for the reaction at 100secs 2mks d Name one factor been investigated above that can affect the rate of reaction 1mk B. You are provided with Solution B containing 4. |
4mks Beaker 1 2 3 4 Volume of acid cm3 10 8 6 4 Volume of water cm3 0 2 4 6 Time second a Plot a graph of volume of acid cm3 against time sec in the graph provided. 3mks b From the graph determine; i Time taken for magnesium to disappear completely at 5cm3 1mk ii Volume of the acid in which magnesium takes 100 seconds to disappear completely 1mk c The rate of reaction for the reaction at 100secs 2mks d Name one factor been investigated above that can affect the rate of reaction 1mk B. You are provided with Solution B containing 4. 26g of potassium dichromate VI per litre K2Cr2O7 Solution C containing 39.2g of ammonium ferrous sulphate per litre NH4 2SO4 .FeSO4.nH2O You are required to: 1. Determine the concentration of solution B in moles per litre 2. Determine the value of n in the formula of compound C PROCEDURE Fill the burette with solution B. Pipette 25cm3 of it and transfer into a conical flask. Titrate against C until the colour turns green. Record your results in the table below. |
1713.17METALWORK 445 3.17.1 Metalwork Paper 1 445 1 For More Free KCSE Past papers Visit www.freekcsepastpapers.com172For More Free KCSE Past papers Visit www.freekcsepastpapers.com173For More Free KCSE Past papers Visit www.freekcsepastpapers.com174For More Free KCSE Past papers Visit www.freekcsepastpapers.com. |
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1-The method of switching the starting winding is by a centrifugal switch. 1 This allows the starting winding to be switched off before the motor reaches its normal speed. 1-Once the motor reaches its normal speed, it runs with only one winding energized. 14 marks b i Load current I2 VP 1 24024000100A cm 21 ii For an ideal transformerOutput power input power 21 I2 voltagepower 21Input current I2 48024000cm 21 50A 21For More Free KCSE Past papers Visit www.freekcsepastpapers.com585 iii Transformer ratio 1 1N2N1V2V14802401:2 13 marks13. A 4 marks b Lamp electrodesSix items labelled 21 3Correctness 1 Total 4 marksFor More Free KCSE Past papers Visit www.freekcsepastpapers.com586Operation- When the supply is switched on with starter switch closed, current flows through inductor L and through lamp electrodes E.-This initial currents heats the lamp electrodes in readiness for striking the lamp.- The starting switch is now opened making a sudden interruption in the current flowing through the inductor and causing a high voltage to be induced.-The voltage starts a discharge between the two lamp electrodes and current rises rapidly due to the inductor.-The starter switch is left open while the lamp is alight, the electrodes maintaining their operating temperature as long as they continue to pass the discharge current.5 marks14. A i Heating.-A ferromagnet metal alloy is heated to bright red hot 1 then allowed to cool in a powerful magnetic field. 1 ii Stroking-This involves stroking a piece of hard steel with one pole of magnet along the length of metal piece. 1 At the end of each stroke the magnet is lifted up and taken through a reasonable curve. The starting end takes the same polarity as the stroking pole of the magnet. 14 marks b 218 parts 21 4 marksLow high current circuit 2 marksTOTAL 6 marksFor More Free KCSE Past papers Visit www.freekcsepastpapers.com587- When the remote switch is closed. Current flows through the coil making it an electromagnet. 1-The electromagnet attracts the armature which closes the circuit. |
14 marks b 218 parts 21 4 marksLow high current circuit 2 marksTOTAL 6 marksFor More Free KCSE Past papers Visit www.freekcsepastpapers.com587- When the remote switch is closed. Current flows through the coil making it an electromagnet.1-The electromagnet attracts the armature which closes the circuit.1-The load in the controlled circuit then operates and when the switch is opened, the load stops to operate.19 marks15. A OR gate ii NAND gate 6 x 21 3 marks b Truth table for NAND gateABQInputs 4 x 21 2Output 4 x 21 24 marks c - Inspect the top plug, cable and kettle for burn-out signs.1- Open the top plug 21 and check for loose connections.- Check for fuse continuity.1- Check for continuity of cables conductors.1- Remove the element and check continuity 1 of the element.1 216 marksFor More Free KCSE Past papers Visit www.freekcsepastpapers.com. |
Www.freekcsepastpapers.comGEOGRAPHY PAPER 1 2 222 IMENTI SOUTH 312 1 GEOGRAPHY PAPER 1 SECTION A 25 marks Answer all the questions in this section 1. A Differentiate between physical and human environment. 2 marks b State three reasons why it s important to study Geography. 3 marks 2. A Define a meteor. 2 marks b State three characteristics of comets. 3 marks 3. A What is a mineral? 2 marks b Give three examples of non-metallic minerals. 3 marks 4. A Define climate change. 2 marks b List three common events that are associated with climate change. 3 marks 5. Give five characteristics of tundra climates. 5 marks SECTION B 75 marks Answer question 6 compulsory and any other two questions from this section 6. Study the map provided Kisumu East map extract, East Africa 1:50,000 Kenya and answer the questions that follow. A i Give six figure grid reference for the trigonometric station SKP 21. 2 marks ii Measure the distance of the provincial regional boundary from the water works station 0199 to 0997 in kilometers. 2 marks b Describe how relief has influenced settlement in the area covered by the map. 6 marks c Name two types of natural vegetation found in the area covered by the map. 2 marks d Citing evidence from the map, state three social functions of Kisumu East. 6 marks e i Draw a rectangle measuring 16cm by 12cm to enclose the area bound by Eastings 95-98 and Northings 80-83. On the rectangle mark and name; Lake Swamp River Luando 6 marks ii Name the title of the map. 1 mark 7. A i What is soil degeneration? 2 marks ii Name three types of soil degeneration. 3 marks b i State two factors that contribute to soil leaching. 2 marks ii List five characteristics of desert soils. 5 marks iii State three importance of soil texture. |
3 marks b i State two factors that contribute to soil leaching. 2 marks ii List five characteristics of desert soils. 5 marks iii State three importance of soil texture. 3 marks c Students from your school carried out field study of soils found in Nyika Plateau. I State three methods they are likely to use to collect data. 3 marks ii Give three characteristics of soils that they are likely to study. 3 marks d State four ways of managing and conserving soils in Kenya. 4 marks 8. A i What is a river divide. 1 mark ii Describe three ways by which a river transports its load. 6 marks b Describe the characteristics of a river in its Old Stage. 7 marks c Describe each of the following drainage systems and patterns. I Superimposed drainage system. 3 marks ii Centripetal drainage pattern. 2 marks d You have planned to carry out a field study of a river in its youthful stage. I State two ways in which you would prepare for the study. 2 marks ii Name two features you are likely to study. 2 marks iii List two problems you are likely to experience during the study. 2 marks www.freekcsepastpapers.comGEOGRAPHY PAPER 1 2 223 9. A i What are earthquakes. 2 marks ii Name three belts of the world associated with earthquakes. 3 marks iii Give four reasons why the above belts are associated with earthquakes. 4 marks b Describe the characteristics of the following earthquake waves. Primary waves. 3 marks c Explain four natural causes of earthquakes. 8 marks d Give five effects of earthquakes to human activities. 5 marks 10. A i What is underground water. 2 marks ii List three sources of underground water. 3 marks iii State four factors that influence the occurrence of underground water. 4 marks iv State three importance of underground water. 3 marks b Give three conditions necessary for the development of Karst scenery. 3 marks c The following diagram represents a feature found in a Karst Scenery. Use it to answer the questions that follow. I Name the parts labelled X and Z. |
3 marks c The following diagram represents a feature found in a Karst Scenery. Use it to answer the questions that follow. I Name the parts labelled X and Z. 2 marks ii Describe the formation of the feature marked Y 3 marks d State the significance of a Karst landscape. 5 marks IMENTI SOUTH 312 2 GEOGRAPHY PAPER 2 SECTION A 25 marks Answer all the questions in this section 1. A State two factors that are considered in determining mining method. 2 marks b List down three uses of soda ash mined in L. Magadi. 3 marks 2. A Differentiate between forests and forestry. 2 marks b State three features of soft wood forests. 3 marks 3. A Identify two characteristics of intensive commercial agriculture. 2 marks b List down three physical factors favouring dairy farming in Denmark. 3 marks 4. A State two aims of setting up of Perkerra irrigation scheme. 2 marks b List down three physical factors that influenced the location of Mwea-Tebere irrigation. 3 marks 5. A Define the term fishing. 2 marks b State three ways in which the convergence of cold and warm ocean current affect fishing. 3 marks X Y Zwww.freekcsepastpapers.comGEOGRAPHY PAPER 1 2 224 SECTION B 75 marks Answer question 6 compulsory and any other two questions from this section 6.a i List down three factors that determine the distribution of forests in Kenya. 3 marks ii Study the data in the following table and answer questions that follows. The table shows the status of forests in Kenya between 2006 to 2009. In hectares. Year Area Open woodland Indigenous Tree farm lands Private plantation forests 2006 6800 4700 2400 800 2007 7200 3800 2000 400 2008 6400 1400 1900 500 2009 5400 4600 2000 700 Calculate the percentage decrease in the area under open woodland forest in Kenya. 3 marks b i Draw a compound bar graph to represent the data above. Use a scale of 1cm represent 1000 hactares. |
Year Area Open woodland Indigenous Tree farm lands Private plantation forests 2006 6800 4700 2400 800 2007 7200 3800 2000 400 2008 6400 1400 1900 500 2009 5400 4600 2000 700 Calculate the percentage decrease in the area under open woodland forest in Kenya. 3 marks b i Draw a compound bar graph to represent the data above. Use a scale of 1cm represent 1000 hactares. 8 marks ii State three advantages of using compound bar graph to represent data. 3 marks c Explain the differences of exploitation of soft wood in Kenya and Canada under the following headings. I Period of harvesting. 2 marks ii Transportation. 2 marks d Highlight four ways in which the clearing of forests has affected the natural environment in Kenya. 4 marks 7.a i Name two fossil fuels and energy minerals found on the earth crust. 2 marks ii State two alluvial mining methods applied in East Africa. 2 marks b i List down three main conditions needed for the formation of petroleum reservoir. 3 marks ii Describe the process of gold processing in South Africa. 8 marks c Students of Mbea school wanted to carry out a field study on mining around their school. I The students used questionnaire to collect data. State three considerations they had while preparing the questionnaire. 3 marks ii The students wanted to analyse the data collected from the field. List down four ways theycould use in data analysis. 4 marks d What three problems could the students have experienced during the field study? 3 marks 8.a i Name two areas within western region sugar Belt where large scale sugarcane cultivation ispracticed. 2 marks ii Explain three human requirements that favour sugarcane growing in Kenya. |
4 marks d What three problems could the students have experienced during the field study? 3 marks 8.a i Name two areas within western region sugar Belt where large scale sugarcane cultivation ispracticed. 2 marks ii Explain three human requirements that favour sugarcane growing in Kenya. 3 marks b i Name two diseases which affect sugarcane. 2 marks ii List down two disadvantages of shade trees in cocoa cultivation. 2 marks c Explain four contributions of cocoa to Ghana s economy. 8 marks d Briefly describe the process of cocoa cultivation in Ghana. 5 marks e Name three cocoa growing areas in Ghana. 3 marks 9.a i Define the term fisheries. 2 marks ii State two importance played by the presence of indented coastline in fishing industry. 2 marks b i Apart from indented coastline explain four factors that have contributed to large scalefishing in North-west pacific. 8 marks www.freekcsepastpapers.comGEOGRAPHY PAPER 1 2 225 ii Name three fish species found in inland fishing grounds which have large economic value. 3 marks c Give five limitations hindering the development of marine fishing in East Africa. 5 marks d i State three conservation methods advocated by Kenya Government in fishing industry. 3 marks ii Name two methods used in deep sea fishing. 2 marks 10. A i Differentiate between wildlife and tourism. 2 marks ii List down two features of game reserve. 2 marks b Explain four factors influencing the distribution of wildlife in E. Africa. 8 marks c i State three reasons why National parks have been established in Kenya. 3 marks ii List down four reasons why domestic tourism is encouraged in Kenya. 4 marks d Explain three differences between tourism in Kenya and Switzerland. 6 marks IMENTI SOUTH GEOGRAPHY PAPER 1 MARKING SCHEME 1. A Differentiate between physical and human environment. 2mks Physical environment refers to features that are natural although their presence have influenced human activities while human environment comprises of activities of people on the earths surface. 2mks b State three reasons why it is important to study Geography. 3mks It promotes awareness on sustainable use of resources. |
2mks Physical environment refers to features that are natural although their presence have influenced human activities while human environment comprises of activities of people on the earths surface. 2mks b State three reasons why it is important to study Geography. 3mks It promotes awareness on sustainable use of resources. It prepares one for career opportunities. It enables learners to manage time properly. It promotes the development of skills and critical thinking. It creates awareness about the country and the rest of the World. It helps promote national and international understanding. 2. A Define a meteor 2mks These are heavenly bodies which burn up and disappear as they enter the earths atmosphere from the universe. B State three characteristics of comets. 3mks They move along oval-shaped orbits. Have a head made up of frozen gases,. Dust particles and rocks. The sun is located at one end of their orbit. The tail disappears as the move near the sun. 3. A What is mineral 2mks This is naturally occurring, crystalline, organic substance with a definite chemical and physical properties. B Give three examples of non-metallic minerals. Coal - Sulphur - Petroleum Potash - Silicates - Graphite Asbestos - Nitrates - Trona Flousphar - Phosphates - Diamond 3mks 4. A Define climate change. 2mks This is the establishment of a new environmental and atmospheric states with change sin elements such as temperature and precipitation, or long term shifts in temperatures and other weather patterns. B List three common climatic events that are associated with climate change. 3msk Floods Drought Frost Heat waves www.freekcsepastpapers.comGEOGRAPHY PAPER 1 2 237 MOKASA 1 JOINT EXAMINATION 312 1 GEOGRAPHY PAPER 1 SECTION A: 25 MARKS Answer ALL questions in this section. 1. A What is physical Geography? 2marks b Give three divisions of physical Geography. 2marks 2. State four effects of rotation of the earth 4marks 3. The diagram below represents zones of natural vegetation on a mountain. Use it to answer questions that follow a Identify the vegetation zones marked X and Y. |
State four effects of rotation of the earth 4marks 3. The diagram below represents zones of natural vegetation on a mountain. Use it to answer questions that follow a Identify the vegetation zones marked X and Y. 2marks b State four characteristics of tropical rainforest vegetation. 4marks 4. A Identify two erosional processes in a desert landscape. 2marks b Describe deflation as wind erosional process 3marks 5. A Define a lake 2marks b Give three reasons why some rift valley lakes are fresh water. 3marks SECTION B Answer question 6 and any other two question in this section. 6. A Study the map of Kisumu East 1:50,000 sheet 116 2 provided and answer the following questions. I What type of map is Kisumu East map extract? 1mark ii Give two scales that have been used in the map extract. 2marks iii What is the bearing of the trigonometrical station at grid square 0383 from the Air Photo Principal Point at grid square 0281? 2marks b . I . Measure the length of the All Weather Road Bound Surface B2 1 from the junction at Grid square 9793 to the western edge of the map extract. Give your answer in kilometer. 2marks ii . What is the altitude of the highest point in the area covered by the map? 2marks c . Draw a rectangle measuring 16cm by 10cm to represent the area enclosed by Eastings 02 and 10 P X Tropical Rainforest Y Height in metreswww.freekcsepastpapers.comGEOGRAPHY PAPER 1 2 238 and Northing 90 and 00. 1mark On the rectangle, mark and name the following. 4marks Nyando escarpment. All Weather Road Bound Surface C543 1 Prison Agricultural Sugar Research Station. D . I. Describe the drainage of the area covered by the map. 5marks ii. Citing evidence from the map, identify three social services offered in Kisumu Municipality. 6marks 7. A . The diagram below shows the structure of the earth. Use it to answer the question that follows. I. Name the parts marked : 2marks P Q ii. |
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