Account for the difference in distribution of the colouration with iodine in the two specimens. Structure of the Seed
A typical seed consists of a seed coat enclosing an embryo. The seed coat is the outer covering which, in most seeds, is made
-Remains of style
Position of plumule
Position of radicle Scutellum
Attachment to External Parent plant
Position of radicle
Micropyle Hilum
Testa
Structure of monocotyledonous seed (maize grain)
External (bj Structure of dicotyledonous seed
Fig. 4.4: Structure of seeds
up of the two layers, an outer testa and inner one, the legmen. The testa is thick; the tegmen is a transparent membrane tissue. The two layers protect the seed bacteria, fungi and other organisms whk may damage it. There is a scar called hilurn on one part of the seed. This is point where the seed had been attached the seed stalk or funicle. Near one end of 1 hilum is a tiny pore, the micropyle. This allows water and air into the embryo, embryo is made up of one or two seed leavi or cotyledons, a plumule (embryonic sh( and a radicle (the embryonic root). The of the radicle is opposite the micropyle. In some seeds the cotyledons swollen as they contain stored food for growing plumule and radicle. Such seeds, called non-endospermic seeds. In ot cases, the seeds have their food stored in: endosperm. Such seeds are call endospermic seeds. Seeds with one cotyk are referred to as monocotyledonous wi those with two are referred to dicotyledonous. This is the major basis i differentiation between the two large cb of plants, the monocotyledonae aa dicotyledonae. Scutellum
Cotyledon
Coieoptile
Plumule
Radicle
Coleorhiza
Internal
Plumule
Radicle
Cotyledon
Internal
Fused pericaT and testa
Dormancy in Seeds
The embiyo of a dry, fully developed seed usually passes through a period of rest after ripening period. During this time the seed performs all its life (physiological) processes very slowly and uses up little food. This is a period of dormancy.


Scutellum
Cotyledon
Coieoptile
Plumule
Radicle
Coleorhiza
Internal
Plumule
Radicle
Cotyledon
Internal
Fused pericaT and testa
Dormancy in Seeds
The embiyo of a dry, fully developed seed usually passes through a period of rest after ripening period. During this time the seed performs all its life (physiological) processes very slowly and uses up little food. This is a period of dormancy. Even if all the favourable environmental conditions for germination are provided to the seed during this period of dormancy, the seed will not germinate. This is due to the fact that the seed embryo may need to undergo further development before germination. Some seeds can germinate immediately after being_shed from the parent plant (e.g. most tropical plants) while others must pass through dormancy period, lasting for weeks, months or even years before the seed can germinate. Dormancy provides the seeds with enough time for dispersal so that they can germinate in a suitable environment. It also enables seeds to survive during adverse environmental conditions without depleting their food reserves. The embryo has time to develop until favourable conditions are available e.g. availability of water. Factors that Cause Dormancy
Embryo may not yet be fully developed. Presence of chemical inhibitors that inhibit germination in seeds e.g.abscisic acid. Very low concentrations of hormones e.g. gibberellins and enzymes reduces the ability of seeds to germinate. Hard and impermeable seed coats prevent entry of air and water in some seeds e.g. wattle. In some seeds the absence of certain wavelengths of light make them remain dormant e.g. in some lettuce plants. Freezing of seeds during winter lowers their enzymatic activities rendering them dormant. Ways of Breaking Dormancy
When the seed embryos are mature then the seed embryos can break dormancyand germinate. Increase in concentration of hormones e.g. cytokinins and gibberellins stimulate germination. Favourable environmental factors such as water, oxygen and suitable temperature. Some wavelengths of light trigger the production of hormones like gibberellins leading to breaking of dormancy. Scarification i.e. weakening of the testa is needed before seeds with hard impermeable seed coats can germinate. This is achieved naturally by saprophytic bacteria and fungi or by passing through the gut of animals.


Scarification i.e. weakening of the testa is needed before seeds with hard impermeable seed coats can germinate. This is achieved naturally by saprophytic bacteria and fungi or by passing through the gut of animals. In agriculture the seeds of some plants are weakened by boiling, roasting and cracking e.g. wattle. Seed Germination
The process by which the seed develops into a seedling is known as germination. It refers to all the changes that take place when a seed becomes a seedling. At the beginning of germination water is absorbed into the seed through the micropyle in a process known as imbibition and causes the seed to swell. The cells of the cotyledons become turgid and active. They begin to make use of the water to dissolve and break down the food substances stored in the cotyledons. The soluble food is transported to the growing plumule and radicle. The plumule grows into a shoot while the radicle grows into a root. The radical emerges from the seed through micropyle, bursting the seed coat as it does so. Conditions Necessary for Germination
Seeds can easily be destroyed by unfavourable conditions such as excessive heat, cold or animals. Seeds need certain conditions to germinate and grow. Some of these conditions are external, for example water, oxygen and suitable temperature while others are internal such as enzymes, hormones and viability of the seeds themselves. Water
A non-germinating seed contains very little water. Without water a seed cannot germinate. Water activates the enzymes and provides the medium for enzymes to act and break down the stored food into soluble form. Water hydrolyses and dissolves the food materials and is also the medium of transport of dissolved food substances through the various cells to the growing region of the radical and plumule. Besides, water softens the seed coat which can subsequently burst and facilitate the emergence of the radicle. Oxygen
Germinating seeds require energy for cell division and growth. This energy is obtained from the oxidation of food substances stored in the seed through respiration thus making oxygen an important factor in seed germination. Seed in water logged soil or seed buried deep into the soil will not germinate due to lack of oxygen. Temperature
Most seeds require suitable temperature before they can germinate. Seeds will not germinate below 0°C or above 47° C. The optimum temperature for seeds to germinate is 30°C.


Temperature
Most seeds require suitable temperature before they can germinate. Seeds will not germinate below 0°C or above 47° C. The optimum temperature for seeds to germinate is 30°C. At higher temperature the protoplasm is killed and the enzymes in the seed are denatured. At very low temperatures the enzymes become inactive. Therefore, the protoplasm and the enzymes work best within the optimum temperature range. The rate of germination increases with temperature until it reaches an optimum. This varies from plant to plant. Enzymes
Enzymes play a vital role during germination in the breakdown and subsequent oxidation of food. Food is stored in seeds in form of carbohydrates, fats and proteins which are in insoluble form. The insoluble food is converted into a soluble form by the enzymes. Carbohydrates are broken down into glucose by the diastase enzyme, fats into fatty acids and glycerol by lipase, and proteins into amino acids by protease. Enzymes are also necessary for the conversion of hydrolysed products to new plant tissues. Hormones
Several hormones play a vital role in germination since they act as growth stimulators. These include gibberellins and cytokinins. These hormones also counteract the effect of germination inhibitors. Viability
Only seeds whose embryos are alive and healthy will be able to germinate and grow. Seeds stored for long periods usually lose their viability due to depletion of their food reserves and destruction of their embryo by pests and diseases. Study Question 4
In an experiment to investigate the effect of neat on germination of seeds, ten bags each containing 60 pea seeds were placed in a water-bath maintained at 85°C . After every two minutes a bag was removed and seeds contained in it planted. The number that germinated was recorded. The procedure used for pea seeds was repeated for wattle seeds. The results obtained were as shown in the table 4,2,
(a)Using a suitable scale and on the same axes, draw graphs of time in hot water against number of seeds that germinated for each plant. Use horizontal axis for time and the verticalaxis for the seeds that germinated. Explain why the ability of pea seeds to germinate declined with time of exposure to heat. Explain why the ability of the wattle seeds to germinate improved with time of exposure to heat.


Use horizontal axis for time and the verticalaxis for the seeds that germinated. Explain why the ability of pea seeds to germinate declined with time of exposure to heat. Explain why the ability of the wattle seeds to germinate improved with time of exposure to heat. Practical Activity 3
To investigate conditions necessary for seed germination
Requirements
Cotton wool, seeds, water, six fiat bottomed flasks, 2 corks, 2 test-tubes, blotting paper, incubator, refrigerator, thermometer, pyrogallic acid and sodium hydroxide. Procedure
Prepare three set-ups as shown in figure 4.5. Leave the set-ups to stand for five days. Record all the observable changes that have taken place in the flasks hi each set up in a table form as shown
Study Question 5
Which condition was being investigated in set-up I, II and III? For each set-up explain the results obtained. What was the role of flask B in each set-up? Types of Germination
The nature of germination varies in different seeds. During germination the cotyledons may be brought above the soil surface. This type of germination is called epigeal germination. If during germination the cotyledons remain underground the type of germination is known as hypogeal. SET UP 1
Pyrogallic acid + NaOH
Cotton wool
Seeds Moist
Water
SET UP 2
Moist cotton wool
Dry cotton wool
SETUPS
Fig. 4.5: Set-up for investigating conditions necessary for germination
Epigeal Germination
During the germination of a bean seed, the radicle grows out through the micropyle. It grows downwards into the soil as a primary root from which other roots arise. The part of the embryo between the cotyledon and the radicle is called the hypocotyl. This part curves and pushes upwards through the soil protecting the delicate shoot tip. The hypocotyls then straightens and elongates carrying with it the two cotyledons which turn green and leafy. They start manufacturing food for the growing seedling. The plumule which is lying between two cotyledons, begins to grow into first foliage leaves which start manufacturing food. Hyopgeal Germination
In maize, the endosperm provides food to the embryo which begins to grow.


They start manufacturing food for the growing seedling. The plumule which is lying between two cotyledons, begins to grow into first foliage leaves which start manufacturing food. Hyopgeal Germination
In maize, the endosperm provides food to the embryo which begins to grow. The radicle along with a protective covering(c(?/eorfci2a) grows out of the seed. The epicotyl is the part of the embryo between the cotyledon and the plumule. The epicotyl elongates and the plumule grows out of the coleoptile and forms the first foliage leaves. The seedling now begins to produce its own food and the endosperm soon shrivels. This type of germination in which the cotyledon remains below the ground is known as hypogeal germination. Practical Activity 4
To investigate epigeal and hypogeal germination
Requirements
Tin or box, soil, water, maize grains and bean seeds. Procedure
Place equal amounts of soil into two containers labelled A and B. In A, plant a few maize grains.In B, plant a few bean seeds. Water the seeds and continue watering daily until they germinate. Place your set-ups on the laboratory bench. Observe daily for germination. On the first day the seedlings emerge from the soil, observe them carefully with
regard to the soil level. Carefully uproot one or two seedlings from each set. Observe and draw the seedlings from each set Label the parts and indicate the soil level on your diagram. On the fifth day since emergence, again uproot another seedling. Observe and draw. Indicate the soil level on your diagram.. Tabulate the differences between the two types of germination studied. Cotyledon Plumule
Radicle
Root
Cotyledon Hypocotyf
Fig. 4.6 (a): Epigeal germination for castor seeds
Plumule
Coleoptile
Scutellum
Coleorhiza
Primary and Secondary Growth
The region of growth in plants is found in localised areas called meristems as shown . A meristem is a group of undifferentiated cells in plants which are capable of continuous mitotic cell division.


Cotyledon Plumule
Radicle
Root
Cotyledon Hypocotyf
Fig. 4.6 (a): Epigeal germination for castor seeds
Plumule
Coleoptile
Scutellum
Coleorhiza
Primary and Secondary Growth
The region of growth in plants is found in localised areas called meristems as shown . A meristem is a group of undifferentiated cells in plants which are capable of continuous mitotic cell division. The main meristems in flowering plants are found at the tips of shoots and roots, in young leaves, at the bases of the inter-nodes, and in
Apicai meristem
Leaf primordium
Vascular tissues
" beginning to form
Epidermis xylem Phloem Pericycte
Cortex
Medulla Cambium
(c) Epidermis
Node
Phloem
Xylefti Epidermis
Cortege
Endodermis
Root cap
Zone of cell division
Zone of cell elongation (expansion)
Zone Trf cell
differentiation
Permanent tissues
Fig. 4.7(a) and (b): Longitudinal section of the root tip and apex Fig. 4.7(c) and (d): Transverse section of the stem and rooi
zone
vascular cambium and cork cambium. T
he meristems at the tips of the shoots and the roots are known as apical meristems and are responsible for primary growth. The cambium meristems are responsible for secondary growth. Primary Growth
Primary growth occurs at the tips of roots and shoots due to the activity of apical meristems. These meristems originate from the embryonic tissues. In this growth there are three distinctive regions, the region of cell division, cell ejpngarion and eel] differentiation. See figure 4.7. The regipn of cell division is an area of actively dividing meristematic cells. These cells have thin cell walls, dense cytoplasm and no vacuoles. In the region of cell elongation, the cells become enlarged to their maximum size by the stretching of their walls. Vacuoles start forming and enlarging. In the region of ceH differentiation the cells attain their permanent size, have large vacuoles and thickened watt cells. The cells also differentiate into tissues specialised for specific functions.


Vacuoles start forming and enlarging. In the region of ceH differentiation the cells attain their permanent size, have large vacuoles and thickened watt cells. The cells also differentiate into tissues specialised for specific functions. Primary growth results into an increase in the length of shoots and roots. Study Question
;:Mgure;4-S indkate the appearance of cells at different regions at the apical meristems.Nudeus -Cytoplasm
Fig. 4.8
Rearrange them into three regions:
Zone of cell division. Zone of cell elongation.; -,
Zone of cell differentiation. (jb) Name specialised tissues formed at tl
zone of cell differentiation. Region of Growth in a root
This is determined by taking a young germinating seedling whose radicle is then marked with the Indian ink at intervals of 2 mm. The seedling is left to grow for sometime (about 24 hours or overnight) and then the ink marks are examined. When the distance between successive ink marks are measured, it is found that the first few ink marks, especially between the 2nd and 3"1 mark above tip of root have increased significantly. This shows that growth has occurred in the region just behind the tip of the root. The difference between the length of each new interval and the initial interval of 2 mm gives the increase in the length of that interval during that period of time. From this the rate of growth of the root region can be calculated. See figure 4.9. „Increase in length . „_
Growth = ^ . .—^— X 100
Original length
Practical Activity 5 To determine the region of growth in roots
Requirements
Germinating bean seeds with radicle of about 1cm in length, cork, pin, beaker or gas jar, water, Indian ink, blotting paper or filter paper, marker and ruler marked in mm. Procedure
Bent wire
Ruler
Take the germinating been seed, andusing a blotting paper, dry the radicaltaking care not to damage the root. Using a marker and ruler make light inkmarks 2mm apart along the length ofthe root. See figure 4.10(a). 4. 5
Make a drawing of the marked root. Pin the seedling onto the cork and place it in the beaker containing a little water. See figure 4.10(b). Leave it overnight. Take out the seedling and examine the ink marks. 6.


Leave it overnight. Take out the seedling and examine the ink marks. 6. 7. Measure the distances between the successive ink marks and record. Make a well labelled drawing of the seedling at the end of the experiment and compare with the drawing of the. seedling at the start of the experiment. Study Question 7
What part of the radicle has the inkmarks moved further apart? Give an explanation for your answersin (a) above. What is the increase in length withineach interval? Work out the rate of growth for theroot
Secondary Growth
Secondary growth results in an increase in width or girth due to activity of the cambium. In secondary growth new tissues are formed by vascular cambium and cork cambium. In monocotyledons plants there are no cambium cell in the vascular bundles.The growth in diameter is due to the enlargement of the primary cells. Secondary growth in dicotyledonous pjants begins with the division of vascular cambium to produce new cambium cells between the vascular bundles. This forms a continuous cambium ring. These cambium cells divide to form the new cells that are added to the older ones. The cambium cells have now become meristematic. The new cells produced to the outer side of cambium differentiate to become secondary phloem and those to the inner side differentiate to become the secondary xylem. More secondary xylem is formed than secondary phloem. The interfascuiar cambium a/so cuts orTparenchymatous cells which form secondary medullary rays as seen in figure 4.11 (a), (b) and (c). As a result of the increase in the volume of the secondary tissues, pressure is exerted on the outer cells of the stem. This results in stretching and rupturing of the epidermal cells. In order to replace the protective outer layer of the stem, a new band of cambium cells are formed in the cortex. These cells, called cork cambium orphellogen originate from the cortical cells. The cork cambium divides to produce new cells on either side. The cells on the inner side of the cork cambium differentiate into secondary cortex and those produced on the outer side become cork cells. Cork cells are dead with thickened walls. Their walls become coated with a waterproof substance called suberin. The cork cells increase in number and become the bark of the stem. This prevents loss of water, infection from fungi and damage from insects.


Their walls become coated with a waterproof substance called suberin. The cork cells increase in number and become the bark of the stem. This prevents loss of water, infection from fungi and damage from insects. The corky bark is also resistant to fire and thus acts as an insulatory layer. The bark is normally impermeable to water and respiratory gases. Periodically the cork cells, instead of being tightly packed, they form a loose mass. This mass is known as Jenticel. The lenticles make it possible for
Transverse section of dicotyledonous stem
Epidermis Primary phloem
Secondary phloem
Secondary xylem
Primary xy/em
Cortex
Beginning of secondary growth in dicot stem
Primary phloem
Secondary ph/oem
Secondary xylem Primary xylem
Epidermis Medullary ray
Cambium ring
Epidermis
Cork cell Cork cambium Secondary cortex Primary cortex
Fig. 4.12: Section through a lenticel
The rate of secondary growth in a stem varies with seasonal changes. During rainy season, xylem vessels and tracheids are formed In large numbers. These cells are large, have thin walls and the wood has a light texture. In the dry season, the xylem and trancheids formed are few in number. They are small, thick-walled and their wood has a dark texture. This leads to the development of two distinctive layers within the secondary xylem formed m a year, called annual rings. See figure 4.13. It is possible to determine the age of a tree by counting the number of annual rings. Furthermore climatic changes of the past years can be infered from the size of the ring. Primary phloem Secondary phloem
Cambium ring Medullary ray Pith
Primary xylem Cortex
Fig. 4.13: Annual rings
Cork
Role of Growth Hormones in Plants
Plant hormones are chemicals produced in very small amounts within the plant body, and play a very important part in regulating plant growth and development. Most growth hormones are produced at the tip of a shoot and transported downwards to the root. The root tip produces very small quantities of the hormones. There are many different types of plant hormones and one well-known group is the auxins. Indoie acetic acid (IAA) is one best known auxin. Auxins are produced at the shoot and root tips.


There are many different types of plant hormones and one well-known group is the auxins. Indoie acetic acid (IAA) is one best known auxin. Auxins are produced at the shoot and root tips. Maximum influence on growth in plants occurs when auxins are produced simultaneously with other plant hormones e.g. gibberellins. Maximum growth response in stems requires more IAA than tn roots. Auxins are known to have various effects on the growth and development in plants. They stimulate cell division and cell elongation in stems and roots leading to primary growth. Auxins cause tropic responses, which are growth responses in plants due to external stimuli acting from a given direction. On the other hand IAA stimulates the growth of adventitious roots which develop from the stem rather than tbe main root. Cuttings can be encouraged to develop roots with the help of IAA. If the cut end of a stem is dipped into IAA, root sprouting is faster. IAA is also used to induce parthenocarpy. This is the growth of an ovary into a fruit without fertilisation. This is commonly u^ed by horticulturalists to bring about a good crop of fruits particularly pineapples. Auxins are known . to inhibit development of side branches from lateral buds. They therefore enhance apical dominance. During secondary growth auxins Play an important role by initiating cell division in the cambium and differentiation of these cambium cells into vascular tissues. Auxins in association with other plant hormones such as the cytokinins induce the formation of callus tissue which causes the healing of wounds. When the concentration of auxins falls in the plant, it promotes formation of an abscission layer leading to leaf fall. A synthetic auxin, 2,4-dichlorophenoxyacetic acid (2,4-D) induces distorted growth and excessive respiration leading to death of the plant. Hence it can be used as a selective weed killer. GibbereHins are another important group of plant growth hormone. GibbereHins are a mixture of compounds and have a very high effect on growth. The most important in growth is gibberellic acid. Gibbereilins are distinguished from auxins by their stimulation of rapid cell division and cell elongation in dwarf varieties of certain plants. Dwarf conditions are thought to be caused by a shortage of gibberellins due to a genetic deficiency. Gibberellins are important in fruit formation.


Gibbereilins are distinguished from auxins by their stimulation of rapid cell division and cell elongation in dwarf varieties of certain plants. Dwarf conditions are thought to be caused by a shortage of gibberellins due to a genetic deficiency. Gibberellins are important in fruit formation. They induce the growth of ovaries into fruits after fertilisation. They also induce parthenocarpy. Gibberellins also promote formation of side branches from lateral buds and breaks dormancy in buds. This is common in species of temperate plants whose buds become dormant in winter. In addition, this hormone also inhibits sprouting of adventitious roots from stem cuttings, it retards formation of abscission layer hence reduces leaf fall. Gibberellins also break seed dormancy by activating the enzymes involved in the breakdown of food substances during germination. Cytokuuns also known as kinetins, are growth substances which promote growth in plants when they interact with auxins. In the presence of auxins, they stimulate cell division thereby bringing about growth of
roots, leaves and buds. They also stimulate formation of the callus tissues in plants. The callus tissue is used in the repair of wounds in damaged parts of plants. Cytokinins promote flowering and breaking of seed dormancy in some plant species. They also promote formation of adventitious roots from stems and stimulate lateral bud development in shoots. When in high concentration cytokinins induce cell enlargement of leaves but in low concentration they encourage leaf senescence and hence leaf fall. Ethylene is a growth substance produced in plants in gaseous form. Its major effect in plants is that it causes ripening and falling of fruits. This is widely applied in horticultural farms in ripening and harvesting of fruits. It stimulates formation of abscission layer leading to leaf fall, induces thickening of stems by promoting cell division and differentiation at the cambium meristem. But it inhibits stem elongation. Ethylene promotes breaking of seed dormancy in some seeds and flower formation mostly in pineapples. Abscisic acid is a plant hormone whose effects are inhibitory in nature. It inhibits seed germination leading to seed dormancy, inhibits sprouting of buds from stems and retards stem elongation. In high concentration, abscisic acid causes closing of the stomata. This effect is important in that it enables plants to reduce water loss. It also promotes leaf and fruit fall.


In high concentration, abscisic acid causes closing of the stomata. This effect is important in that it enables plants to reduce water loss. It also promotes leaf and fruit fall. Another hormone, florigen is produced in plants where it promotes flowering. Apical Dominance
Although auxins, particularly IAA are important stem and root elongation, they are known to exert profound effects on other aspects of plant growth and development. If an apical bud which normally contains high concentrations of auxins is removed, it is
observed that more lateral buds lower down the stem sprout, producing many branches. This shows that high concentrations of auxins have an inhibitor}' effect on sprouting of lateral buds and therefore hinders growth of many branches. This forms the basis of pruning in agriculture where more branches are required for increased harvest particularly on crops like coffee and tea. The failure of lateral buds to develop in the presence of an apical bud is due to the diffusion of auxins from the shoot apex downwards in concentrations higher than that promoting lateral bud development. Practical Activity 6
To investigate apical dominance in plants
Requirements
Tomato seedlings growing in a tin. Procedure
Cut off the terminal buds from 3seedlings in the tin, leaving the otherseedlings with the terminal buds intact,
Leave the seedlings to continuegrowing for five more days. Study Questions 8
list the differences noticed betweenthe two groups of seedlings? Explainhow the differences come about. From your observations, explain thebasis for pruning tea and coffee. Growth and Development in Animals
In higher animals, most cells with the exception of the nerve cells, retain their power of division. Thus, there is a continued breakdown and replacement of cells. Animal cells undergo rapid cell division and cell differentiation but, unlike plant cells, they undergo very little cell enlargement. In most animals growth occurs through: their life till they die. This type of growth called continuous growth. Arthropods e.g. insects show rapid growth immediately after moulting with periods when no growth increase occurs. This is called discontinuous growth. Insects exhibit two types of reproducti processes. In some insects, the ova in t female are fertilised by the spermatozoa frc the male. This is a typical example of sexi reproduction, common in butterflies ai moths.


Insects exhibit two types of reproducti processes. In some insects, the ova in t female are fertilised by the spermatozoa frc the male. This is a typical example of sexi reproduction, common in butterflies ai moths. In other insects like the black and t green aphids, the eggs are usually product without being fertilised and are able to --- into adult insects. This type of asexual reproduction is referred to ; parthenogenesis. Growth and Development in Insects
Majority of insects lay eggs that hatch int larvae, which is an immature stage, usual! quite different from the adults in morpholog and behaviour. Depending on the insec species a larva is referred to as a grub, maggot or a caterpillar. Generally the larv eats a lot, grows rapidly and sheds its cuticl several times until it reaches full size t< become a pupa. The pupa is an inactive, non feeding stage during which extensivi breakdown and re-organisation of body tissui occur, eventually giving rise to the imago o adult form. Such changes, callec metamorphosis, do occur in butterflies moths, bees, wasps and flies. Insects which pass through these stages, namely, egg-larva-pupa, into imago/adult in their developmenl are said to undergo complete metamorphosis. Development in a Housefly(An example of complete metamorphosis)
When the egg of a housefly is laid, it measures about 1mm in length. The eggs are laid in batches of between 100 to 150. The larvae which hatch from the eggs grow and feed on decaying matter. After several moults and increase in size, a Jarva reaches about 1cm in length. This takes about 5 days. After this, the larva changes into a pupa encased in a pupal case called die puparium, from which the adult fly later emerges. After emergence, the adult tgkes about two weeks of feeding and growing to attain sexual maturity, i.e. the males can mate and the females are able to lay eggs. Figure 4.14 summarises the life cycle of a housefly. Incomplete Metamorphosis
Development in some insects like the locust and cockroaches, involves the.egg hatching into a nymph which e!cie!y resembles the adult in every form, except for size and lack of sexual maturity.


the males can mate and the females are able to lay eggs.

Figure 4.14 summarises the life cycle of a housefly.

Incomplete Metamorphosis
Development in some insects like the locust and cockroaches, involves the.egg hatching into a nymph which e!cie!y resembles the adult in every form, except for size and lack of sexual maturity.

Pupa case Adult pushes out against the case
For such insects to reach the adult, stages, they undergo a series of moults.

before fully acquiring the adult size and attaining the sexual maturity.

These insects are said to undergo incomplete metamorphosis.

Development in a Cockroach(An example of incomplete metamorphosis)
Cockroaches produce eggs enclosed in a case in groups of between 10 - 15.

The case known as ootheca is made up of cfaitm.

The ootheca is usually deposited in moist dark and warm places, for example in cracks of furniture or crevices in walls.

It takes about a month before the small wingless nymphs emerge.

The nymphs feed, and moult about ten times with the total nymphal period lasting about 16 days for all the adult structure to become fully developed.

Role of Hormones in InsectMetamorphosis
In insects metamorphosis is controlled by hormones.

The hormones are produced in three glands namely;
Neurosecretory cells in the brain ganglia, a pair of corpora allata (singular Corpus allatum) located in the mandibular segment and prothoracic glands in the thorax.

During larval stages of the insect the corpora ailata produces juvenile hormone,
This leads to formation of larval cuticle., therefore moulting does not go beyond the larval stage.

When the larva matures, the corpus allatum disintegrates-
At this time the neurosecretory cells stimulate the prothoracic glands to produce moulting hormone (ecdysone).

Ecdysone is responsible for moulting in insects leading to the laying of the adult cuticle.


Study the equation below. Hydrated copper (II) sulphate white Solid T + Colourless Liquid H a) Identify the; i).White solid T ............................................................... ii). C olourless liquid H .......................................................{1 m ark} b) If H ydrated C opper (II) Sulphate had FIVE w ater m olecules, w rite the chemical equation for the above reaction. {1 m ark} .......................................................................................................................... .......................................................................................................... 10. During the 2012 London O lympic G ames, samples from four D ecathlon participants (Morgan, Bolton, Jimmy and Jade) w ere taken and tested for presence of two illegal steroids A and B. Paper chromatography w as used for the test. Steroid A Steroid B Morgan Bolton Jimmy Jade a) Which athlete(s) tested positive for the illegal steroid? {1 m ark} ........................................................................................................................... ............................................................................... b) On the filter paper representation below, draw the results for the Bolton.{2 marks} 1 1 . T h e c u r v e s b e l o w r e p r e s e n t t h e v a r i a t i o n o f t e m p e r a t u r e w i t h t i m e w h e n
pure and impure samples of a solid w ere heated. Solid K Temperature in ˚C Solid F Time in seconds a) Which of the two curves shows the variation in temperature for pure solid? Explain.{2 m arks} b) If 300 grams m ore of the pure substance w as added to the sample, show on the graph the time that the sample the pure substance w ill boil. {½ m ark}
c) On the graph above, indicate the boiling point of the pure substance.{½ m ark} 12. Arnold, a student from Starehe Boys’ C entre Situated 3050m above the sea level boiled 100cm3 of pure w ater. Another student, Annette, from Mombasa 0 m etres above the sea level boiled the same volume of pure water. i. Which of the two students took the longest time to boil w ater? {1mark} .................................................................................................................. ii. Explain your answer in d, i) above? {1 m ark} ........................................................................................................................... ........................................... 13.


Introduction to chemistry 1. Wooden splints F and G were placed in different zones of a Bunsen burner flame.              The diagram below  gives the observations that were made (a) Explain the difference between F and G (b) Name the type of flame that was used in the above experiment 2. The diagrams below represent a list of apparatus which are commonly used in a chemistry laboratory:- (a) Give the correct order of the apparatus, using the letters only, to show the correct arrangement       that can be used to prepare and investigate the nature of PH of a sample of onion solution (b) Name one chemical substance and apparatus that is needed in this experiment 3. (a) When the air-hole is fully opened, the bunsen burner produces a non-luminous flame.                   Explain (b) Draw a labelled diagram of anon-luminous flame 4. (a) What is a drug?


(a) When the air-hole is fully opened, the bunsen burner produces a non-luminous flame.                   Explain (b) Draw a labelled diagram of anon-luminous flame 4. (a) What is a drug? (b) Give two drugs that are commonly abused by the youth. 5. The diagram below shows three methods for collecting gases in the laboratory
(a) Name the methods A and B (b) From the methods above, identify one that is suitable for collecting sulphur (IV) oxide.     Explain 6. A mixture of hexane and water was shaken and left to separate as shown in the diagram below: State the identity of; (i) P ………………………………..……..     (ii) W ………………………………….…. 7. The diagrams below are some common laboratory apparatus. Name each apparatus and              state its use Diagram Name Use
(½mk ) (½mk) (½mk) (½mk) 8.


A mixture of hexane and water was shaken and left to separate as shown in the diagram below: State the identity of; (i) P ………………………………..……..     (ii) W ………………………………….…. 7. The diagrams below are some common laboratory apparatus. Name each apparatus and              state its use Diagram Name Use
(½mk ) (½mk) (½mk) (½mk) 8. The diagram below shows some parts of a Bunsen burner Explain how the parts labelled T and U are suited to their functions
9. The diagram below shows the appearance of two pieces of paper placed in different parts of a non-luminous flame of a Bunsen burner and removed quickly before they caught fire. (a) What do the experiments show about the outer region of the flame? (b) From the above experiment, which part of the flame is better to use for heating?Give a reason 10.


The diagram below shows the appearance of two pieces of paper placed in different parts of a non-luminous flame of a Bunsen burner and removed quickly before they caught fire. (a) What do the experiments show about the outer region of the flame? (b) From the above experiment, which part of the flame is better to use for heating?Give a reason 10. A crystal of copper (II) sulphate was placed in a beaker of water. The beaker was left standing for  two days without shaking. State and explain the observations that were made. 11. Study the information in the table below and answer questions that follow.


A crystal of copper (II) sulphate was placed in a beaker of water. The beaker was left standing for  two days without shaking. State and explain the observations that were made. 11. Study the information in the table below and answer questions that follow.               (Letters given are not real symbols) Ions Electron arrangement Ionic radius (nm) A+ B+ C2+ 2.8 2.8.8 2.8 0.95 0.133 0.065 Explain why the ionic radius of :- (a) B+ is greater than that of A+   (b) C2+ is smaller than the of A+  Simple classification of substances 1. The diagram below shows the heating curve of a pure substance. Study it and answer the  questions that follow:
(a) What physical changes are taking place at points X and Z? (b)Explain what happens to the melting point of sodium chloride added to this substance 2.


              (Letters given are not real symbols) Ions Electron arrangement Ionic radius (nm) A+ B+ C2+ 2.8 2.8.8 2.8 0.95 0.133 0.065 Explain why the ionic radius of :- (a) B+ is greater than that of A+   (b) C2+ is smaller than the of A+  Simple classification of substances 1. The diagram below shows the heating curve of a pure substance. Study it and answer the  questions that follow:
(a) What physical changes are taking place at points X and Z? (b)Explain what happens to the melting point of sodium chloride added to this substance 2. (a) State two differences between luminous flame and non-luminous flame (b) It is advisable to set a Bunsen burner to luminous flame prior to an experiment.                   Explain 3.


(b)Explain what happens to the melting point of sodium chloride added to this substance 2. (a) State two differences between luminous flame and non-luminous flame (b) It is advisable to set a Bunsen burner to luminous flame prior to an experiment.                   Explain 3. The paper chromatography of a plant extract gave the following results: Solvent Number of spots X 6 Y 2 Z 3 (a) Which is the most suitable solvent for purifying the extract? Explain  (b) Ball pen cannot be used to mark solvent front in the above chromatography. Explain 4. Name the process which takes place when:  (a) Solid Carbon (Iv) Oxide (dry ice) changes directly into gas (b) A red litmus paper turns white when dropped into chlorine water (c) Propene gas molecules are converted into a giant molecule 5. A sample of copper turnings was found to be contaminated with copper (II) oxide.


The paper chromatography of a plant extract gave the following results: Solvent Number of spots X 6 Y 2 Z 3 (a) Which is the most suitable solvent for purifying the extract? Explain  (b) Ball pen cannot be used to mark solvent front in the above chromatography. Explain 4. Name the process which takes place when:  (a) Solid Carbon (Iv) Oxide (dry ice) changes directly into gas (b) A red litmus paper turns white when dropped into chlorine water (c) Propene gas molecules are converted into a giant molecule 5. A sample of copper turnings was found to be contaminated with copper (II) oxide. Describe how a sample of copper metal can be separated from the mixture 6. Copper (II) oxide and charcoal are black solids. How would you distinguish between the two solids? 7. a) What is chromatography? b) Give two applications of chromatography 8.


7. a) What is chromatography? b) Give two applications of chromatography 8. The two elements P and R were separately burned in air, the products gave the results             recorded in the table below: ELEMENTS  PHYSICAL STATE AT ROOM TEMPERATURE P SOLID R SOLID Physical states of products White solid powder only Colourless gases L and M Nature of solutions in water Basic L strongly acidic M slightly acidic (a) Suggest the identity of element R. ……………………………………………..…….. (b) Describe how the nature of the solutions of the of the oxides were determined 9 The diagram below represents a paper chromatography for the three brands of soft drinks containing banned artificial food additives.


b) Give two applications of chromatography 8. The two elements P and R were separately burned in air, the products gave the results             recorded in the table below: ELEMENTS  PHYSICAL STATE AT ROOM TEMPERATURE P SOLID R SOLID Physical states of products White solid powder only Colourless gases L and M Nature of solutions in water Basic L strongly acidic M slightly acidic (a) Suggest the identity of element R. ……………………………………………..…….. (b) Describe how the nature of the solutions of the of the oxides were determined 9 The diagram below represents a paper chromatography for the three brands of soft drinks containing banned artificial food additives. 4 1                                   6                                    2                                  7                                  5                                  3 A B C BRANDS OF SOFT DRINKS A and C found to contain the banned artificial food additives. Which numbers indicate the             banned artificial food additives?


The two elements P and R were separately burned in air, the products gave the results             recorded in the table below: ELEMENTS  PHYSICAL STATE AT ROOM TEMPERATURE P SOLID R SOLID Physical states of products White solid powder only Colourless gases L and M Nature of solutions in water Basic L strongly acidic M slightly acidic (a) Suggest the identity of element R. ……………………………………………..…….. (b) Describe how the nature of the solutions of the of the oxides were determined 9 The diagram below represents a paper chromatography for the three brands of soft drinks containing banned artificial food additives. 4 1                                   6                                    2                                  7                                  5                                  3 A B C BRANDS OF SOFT DRINKS A and C found to contain the banned artificial food additives. Which numbers indicate the             banned artificial food additives? 10.


(b) Describe how the nature of the solutions of the of the oxides were determined 9 The diagram below represents a paper chromatography for the three brands of soft drinks containing banned artificial food additives. 4 1                                   6                                    2                                  7                                  5                                  3 A B C BRANDS OF SOFT DRINKS A and C found to contain the banned artificial food additives. Which numbers indicate the             banned artificial food additives? 10. Without using any laboratory chemical, describe a simple laboratory experiment to distinguish between calcium hydrogen carbonate and sodium hydrogen carbonate 11. Substance Q has a melting point of 15oC and boiling point of 70oC.


10. Without using any laboratory chemical, describe a simple laboratory experiment to distinguish between calcium hydrogen carbonate and sodium hydrogen carbonate 11. Substance Q has a melting point of 15oC and boiling point of 70oC. (a) On the same axes, draw the melting point and boiling point graph for Q and the room                   temperature            (b) State the physical state of substance Q at room temperature 12. Cooking oils comprise of a mixture of compounds which have a boiling point range              of 23oC to 27oC. (i) What evidence is then to support the statement that cooking oil is a mixture? (ii)Name another experimental technique that could be used to confirm your answer                   in part (i) above 13.


Cooking oils comprise of a mixture of compounds which have a boiling point range              of 23oC to 27oC. (i) What evidence is then to support the statement that cooking oil is a mixture? (ii)Name another experimental technique that could be used to confirm your answer                   in part (i) above 13. A form 1 student carried out the separation as shown in the set-up below:-           (i)  Identify the method above.................................................................................           (ii) Give one of its disadvantages          (iii) Name a mixture which can be separated by the set-up above 14. What is meant by melting point and boiling point of a substance? 15.


          (ii) Give one of its disadvantages          (iii) Name a mixture which can be separated by the set-up above 14. What is meant by melting point and boiling point of a substance? 15. The apparatus below were used by a student to study the effect of heat on hydrated            copper II sulphate
(a) What is the role of the ice cold water…………… (b) Name liquid P………………………………………………………… (c) What observation is made in the boiling tube
17. The diagram below shows chromatograms of blood samples obtained from three athletes. One athlete used illegal drug to improve performance in competition. (a) Name the line marked  M …………………………………………………. (b)Identify the athlete who used illegal drug ……………... ………………………. 18.


         Displacement reaction              ………………………………………… 19. Give two reasons why a luminous flame is not used for heating purposes 20. Classify the following processes as chemical changes or physical changes             Process                                    physical or chemical          Neutralization                              ………………………………………          Sublimation                                 ………………………………………          Fractional distillation               ………………………………………..          Displacement reaction              ………………………………………… 21. Give two reasons why a luminous flame is not used for heating purposes 22. State two criteria for determining the purity of a substance Substance Water Concentrated sulphuric(VI)acid Concentrated sodium hydroxide
Ethene Slightly soluble Soluble Insoluble Ammonia Very  soluble Very  soluble Very  soluble Hydrogen Slightly soluble Insoluble Insoluble 23.


         Displacement reaction              ………………………………………… 21. Give two reasons why a luminous flame is not used for heating purposes 22. State two criteria for determining the purity of a substance Substance Water Concentrated sulphuric(VI)acid Concentrated sodium hydroxide
Ethene Slightly soluble Soluble Insoluble Ammonia Very  soluble Very  soluble Very  soluble Hydrogen Slightly soluble Insoluble Insoluble 23. Study the information in the table below and answer the questions.                  i) A mixture contains ethene, Hydrogen and ammonia gases. Explain how a sample of                      hydrogen   gas can be obtained  from  this  mixture.   24.a)i) The diagram below show spots of a pure substance A, B, and C on a chromatography                            paper. Spot D is that of a mixture    After development A, B, and C were found to have moved 8cm, 3cm and 6cm respectively.


Study the information in the table below and answer the questions.                  i) A mixture contains ethene, Hydrogen and ammonia gases. Explain how a sample of                      hydrogen   gas can be obtained  from  this  mixture.   24.a)i) The diagram below show spots of a pure substance A, B, and C on a chromatography                            paper. Spot D is that of a mixture    After development A, B, and C were found to have moved 8cm, 3cm and 6cm respectively. D had separated into two spots which had moved 6cm and 8cm On the diagram above;   I. Label the baseline (origin)  II. Show the positions of all the spots after development   ii) Identify the substances present in mixture D b) Describe how solid ammonium chloride can be separated from a solid mixture of                  ammonium chloride and anhydrous calcium chloride c) The table below shows liquids that are miscible and those that are immiscible Liquid L3 L4 L1 Miscible Miscible L2 Miscible Immiscible Use the information given in the table to answer that questions that follow; i) Name the method that can be used to separate L1 and L2 from a mixture of the two ii) Describe how a mixture of L2 and L4 can be separated 25.


                 i) A mixture contains ethene, Hydrogen and ammonia gases. Explain how a sample of                      hydrogen   gas can be obtained  from  this  mixture.   24.a)i) The diagram below show spots of a pure substance A, B, and C on a chromatography                            paper. Spot D is that of a mixture    After development A, B, and C were found to have moved 8cm, 3cm and 6cm respectively. D had separated into two spots which had moved 6cm and 8cm On the diagram above;   I. Label the baseline (origin)  II. Show the positions of all the spots after development   ii) Identify the substances present in mixture D b) Describe how solid ammonium chloride can be separated from a solid mixture of                  ammonium chloride and anhydrous calcium chloride c) The table below shows liquids that are miscible and those that are immiscible Liquid L3 L4 L1 Miscible Miscible L2 Miscible Immiscible Use the information given in the table to answer that questions that follow; i) Name the method that can be used to separate L1 and L2 from a mixture of the two ii) Describe how a mixture of L2 and L4 can be separated 25. A student left some crushed fruit mixture with water for some days. He found the mixture
had  fermented. He concluded that the mixture was contaminated with water and ethanol with boiling point of 100oC and 78oC respectively. The set-up of apparatus below are used to separate the mixture.


  24.a)i) The diagram below show spots of a pure substance A, B, and C on a chromatography                            paper. Spot D is that of a mixture    After development A, B, and C were found to have moved 8cm, 3cm and 6cm respectively. D had separated into two spots which had moved 6cm and 8cm On the diagram above;   I. Label the baseline (origin)  II. Show the positions of all the spots after development   ii) Identify the substances present in mixture D b) Describe how solid ammonium chloride can be separated from a solid mixture of                  ammonium chloride and anhydrous calcium chloride c) The table below shows liquids that are miscible and those that are immiscible Liquid L3 L4 L1 Miscible Miscible L2 Miscible Immiscible Use the information given in the table to answer that questions that follow; i) Name the method that can be used to separate L1 and L2 from a mixture of the two ii) Describe how a mixture of L2 and L4 can be separated 25. A student left some crushed fruit mixture with water for some days. He found the mixture
had  fermented. He concluded that the mixture was contaminated with water and ethanol with boiling point of 100oC and 78oC respectively. The set-up of apparatus below are used to separate the mixture. (i) Name the piece of apparatus labelled W (ii) What is the purpose of the thermometer in the set-up?


D had separated into two spots which had moved 6cm and 8cm On the diagram above;   I. Label the baseline (origin)  II. Show the positions of all the spots after development   ii) Identify the substances present in mixture D b) Describe how solid ammonium chloride can be separated from a solid mixture of                  ammonium chloride and anhydrous calcium chloride c) The table below shows liquids that are miscible and those that are immiscible Liquid L3 L4 L1 Miscible Miscible L2 Miscible Immiscible Use the information given in the table to answer that questions that follow; i) Name the method that can be used to separate L1 and L2 from a mixture of the two ii) Describe how a mixture of L2 and L4 can be separated 25. A student left some crushed fruit mixture with water for some days. He found the mixture
had  fermented. He concluded that the mixture was contaminated with water and ethanol with boiling point of 100oC and 78oC respectively. The set-up of apparatus below are used to separate the mixture. (i) Name the piece of apparatus labelled W (ii) What is the purpose of the thermometer in the set-up? iii) At which end of the apparatus W should tap water be connected?…………………………… (iv) Which liquid was collected as the first distillate? Explain (v) What is the name given to the above method of separating mixture?


A student left some crushed fruit mixture with water for some days. He found the mixture
had  fermented. He concluded that the mixture was contaminated with water and ethanol with boiling point of 100oC and 78oC respectively. The set-up of apparatus below are used to separate the mixture. (i) Name the piece of apparatus labelled W (ii) What is the purpose of the thermometer in the set-up? iii) At which end of the apparatus W should tap water be connected?…………………………… (iv) Which liquid was collected as the first distillate? Explain (v) What is the name given to the above method of separating mixture? (vi) State two applications of the above method of separating mixtures (vi) What properties of the mixture makes it possible for the component to be separated                   by  the above methods? 26.


iii) At which end of the apparatus W should tap water be connected?…………………………… (iv) Which liquid was collected as the first distillate? Explain (v) What is the name given to the above method of separating mixture? (vi) State two applications of the above method of separating mixtures (vi) What properties of the mixture makes it possible for the component to be separated                   by  the above methods? 26. The set-up below was used to separate a mixture:- (a) Name the apparatus missing in the set-up
(b) Give one example of mixture T (c) What is the name of this method of separation
27.a) The diagram below shows a set – up used by a student to find out what happens                   when Copper  (II) sulphate crystals are heated.    (i) State the observations made when the blue copper (II) sulphate crystals  are heated.


26. The set-up below was used to separate a mixture:- (a) Name the apparatus missing in the set-up
(b) Give one example of mixture T (c) What is the name of this method of separation
27.a) The diagram below shows a set – up used by a student to find out what happens                   when Copper  (II) sulphate crystals are heated.    (i) State the observations made when the blue copper (II) sulphate crystals  are heated.     (ii) Identify liquid Y and write an equation for its formation. b) Pellets of sodium hydrogen and anhydrous Copper (II) sulphate were put in separate Petri-     dishes and left in the open for two hours. Explain the observation in each Petri-dish. 28.


    (ii) Identify liquid Y and write an equation for its formation. b) Pellets of sodium hydrogen and anhydrous Copper (II) sulphate were put in separate Petri-     dishes and left in the open for two hours. Explain the observation in each Petri-dish. 28. The chromatography below shows the constituents of a flower extract using an organic solvent:- (a) (i) Name a possible organic solvent you can use for this experiment      (ii) State one property that makes the red pigment to move the furthest distance from M      (iii) Describe how one could get a sample of yellow pigment                   (iv) On the diagram indicate solvent front (b) Describe how Aluminium chloride can be separated from a mixture of aluminium chloride
                 and sodium chloride     29.  Study the information below and answer the questions that follow: Solid Cold water Hot water R Soluble Soluble V Insoluble Insoluble S Insoluble Insoluble  Describe how the mixture of solid R, S, and V can be separated 30.


b) Pellets of sodium hydrogen and anhydrous Copper (II) sulphate were put in separate Petri-     dishes and left in the open for two hours. Explain the observation in each Petri-dish. 28. The chromatography below shows the constituents of a flower extract using an organic solvent:- (a) (i) Name a possible organic solvent you can use for this experiment      (ii) State one property that makes the red pigment to move the furthest distance from M      (iii) Describe how one could get a sample of yellow pigment                   (iv) On the diagram indicate solvent front (b) Describe how Aluminium chloride can be separated from a mixture of aluminium chloride
                 and sodium chloride     29.  Study the information below and answer the questions that follow: Solid Cold water Hot water R Soluble Soluble V Insoluble Insoluble S Insoluble Insoluble  Describe how the mixture of solid R, S, and V can be separated 30. Given a mixture of lead (II) oxide, ammonium chloride and sodium chloride, describe how this              mixture can  be separated to obtain a sample of each.


28. The chromatography below shows the constituents of a flower extract using an organic solvent:- (a) (i) Name a possible organic solvent you can use for this experiment      (ii) State one property that makes the red pigment to move the furthest distance from M      (iii) Describe how one could get a sample of yellow pigment                   (iv) On the diagram indicate solvent front (b) Describe how Aluminium chloride can be separated from a mixture of aluminium chloride
                 and sodium chloride     29.  Study the information below and answer the questions that follow: Solid Cold water Hot water R Soluble Soluble V Insoluble Insoluble S Insoluble Insoluble  Describe how the mixture of solid R, S, and V can be separated 30. Given a mixture of lead (II) oxide, ammonium chloride and sodium chloride, describe how this              mixture can  be separated to obtain a sample of each. 31.       The setup below was used to separate two miscible liquids Q and T              (Boling points; Q =98° C, T=78°C) (a) Identify the mistakes in the setup above (b)Identify Distillate X 32.Name the process which takes place when: a) Solid Carbon (IV) oxide (dry ice) changes directly into gas.


The chromatography below shows the constituents of a flower extract using an organic solvent:- (a) (i) Name a possible organic solvent you can use for this experiment      (ii) State one property that makes the red pigment to move the furthest distance from M      (iii) Describe how one could get a sample of yellow pigment                   (iv) On the diagram indicate solvent front (b) Describe how Aluminium chloride can be separated from a mixture of aluminium chloride
                 and sodium chloride     29.  Study the information below and answer the questions that follow: Solid Cold water Hot water R Soluble Soluble V Insoluble Insoluble S Insoluble Insoluble  Describe how the mixture of solid R, S, and V can be separated 30. Given a mixture of lead (II) oxide, ammonium chloride and sodium chloride, describe how this              mixture can  be separated to obtain a sample of each. 31.       The setup below was used to separate two miscible liquids Q and T              (Boling points; Q =98° C, T=78°C) (a) Identify the mistakes in the setup above (b)Identify Distillate X 32.Name the process which takes place when: a) Solid Carbon (IV) oxide (dry ice) changes directly into gas. b) A red litmus paper turns white when dropped into chlorine water.


Given a mixture of lead (II) oxide, ammonium chloride and sodium chloride, describe how this              mixture can  be separated to obtain a sample of each. 31.       The setup below was used to separate two miscible liquids Q and T              (Boling points; Q =98° C, T=78°C) (a) Identify the mistakes in the setup above (b)Identify Distillate X 32.Name the process which takes place when: a) Solid Carbon (IV) oxide (dry ice) changes directly into gas. b) A red litmus paper turns white when dropped into chlorine water. c) Propene gas molecules are converted into a giant molecule. 33. The following diagram shows a paper chromatogram of substances A, B, C, and D which              are coloured      (a) Indicate the solvent front on the chromatogram      (b) Which substance is pure? ………………………………………..


33. The following diagram shows a paper chromatogram of substances A, B, C, and D which              are coloured      (a) Indicate the solvent front on the chromatogram      (b) Which substance is pure? ………………………………………..      (c) Substance E is a mixture of C and D. Indicate its chromatogram in the diagram 34.       Study the information below and answer the following questions. A mixture contains three             solids   A, B, and C. The solubility of these solids in different liquids is as shown below:-
Solid Water Alcohol Ether A Soluble Insoluble Insoluble B Insoluble Soluble Very soluble C Soluble Soluble Insoluble            Explain how you will obtain sample C from the mixture 35. State and explain the observations made when iodine crystals is heated in a boiling tube?  Acids, bases and combustion 1.


     (c) Substance E is a mixture of C and D. Indicate its chromatogram in the diagram 34.       Study the information below and answer the following questions. A mixture contains three             solids   A, B, and C. The solubility of these solids in different liquids is as shown below:-
Solid Water Alcohol Ether A Soluble Insoluble Insoluble B Insoluble Soluble Very soluble C Soluble Soluble Insoluble            Explain how you will obtain sample C from the mixture 35. State and explain the observations made when iodine crystals is heated in a boiling tube?  Acids, bases and combustion 1. The table below shows solutions A, B and C are tested and observations records as shown: Solution Observations on indicator A Methyl orange turns yellow B Phenolphthalein turns colourless C Litmus turns purple (a) Using the table above, name an acid (b) How does the pH value of 1M potassium hydroxide solution compare with that of                 1M aqueous ammonia? Explain 2.


State and explain the observations made when iodine crystals is heated in a boiling tube?  Acids, bases and combustion 1. The table below shows solutions A, B and C are tested and observations records as shown: Solution Observations on indicator A Methyl orange turns yellow B Phenolphthalein turns colourless C Litmus turns purple (a) Using the table above, name an acid (b) How does the pH value of 1M potassium hydroxide solution compare with that of                 1M aqueous ammonia? Explain 2. The information below gives PH values of solutions V, W, X, Y Z Solution PH values V W X Y Z         2 6.5 11 14 4.5  (a) Which solution is likely to be:       (i) Calcium hydroxide?……………………………………………….


Acids, bases and combustion 1. The table below shows solutions A, B and C are tested and observations records as shown: Solution Observations on indicator A Methyl orange turns yellow B Phenolphthalein turns colourless C Litmus turns purple (a) Using the table above, name an acid (b) How does the pH value of 1M potassium hydroxide solution compare with that of                 1M aqueous ammonia? Explain 2. The information below gives PH values of solutions V, W, X, Y Z Solution PH values V W X Y Z         2 6.5 11 14 4.5  (a) Which solution is likely to be:       (i) Calcium hydroxide?……………………………………………….                   (ii) Rain water?……………………………………………………… (b) Which solution would react most vigorously with Zinc carbonate 3.a) Complete the table below to show the colour of the given indicator in acidic and basic     solutions.


The table below shows solutions A, B and C are tested and observations records as shown: Solution Observations on indicator A Methyl orange turns yellow B Phenolphthalein turns colourless C Litmus turns purple (a) Using the table above, name an acid (b) How does the pH value of 1M potassium hydroxide solution compare with that of                 1M aqueous ammonia? Explain 2. The information below gives PH values of solutions V, W, X, Y Z Solution PH values V W X Y Z         2 6.5 11 14 4.5  (a) Which solution is likely to be:       (i) Calcium hydroxide?……………………………………………….                   (ii) Rain water?……………………………………………………… (b) Which solution would react most vigorously with Zinc carbonate 3.a) Complete the table below to show the colour of the given indicator in acidic and basic     solutions. Indicator Colour in Methyl Orange Acidic Solution Basic Solution Yellow Phenolphthalein Colourless b) How does the PH value of 0.1M potassium hydroxide solution compare with that of 0.1M     aqueous ammonia?


The information below gives PH values of solutions V, W, X, Y Z Solution PH values V W X Y Z         2 6.5 11 14 4.5  (a) Which solution is likely to be:       (i) Calcium hydroxide?……………………………………………….                   (ii) Rain water?……………………………………………………… (b) Which solution would react most vigorously with Zinc carbonate 3.a) Complete the table below to show the colour of the given indicator in acidic and basic     solutions. Indicator Colour in Methyl Orange Acidic Solution Basic Solution Yellow Phenolphthalein Colourless b) How does the PH value of 0.1M potassium hydroxide solution compare with that of 0.1M     aqueous ammonia? Explain. 4. Use the information given below to answer the questions that follow: Solution G H I J K pH 1.5 6.5 13.0 7.0 8.0 (a) Which of the solutions would be used to relieve a stomach upset caused by indigestion? (b) Which solution is likely to be:       (i) Dilute sulphuric acid?


4. Use the information given below to answer the questions that follow: Solution G H I J K pH 1.5 6.5 13.0 7.0 8.0 (a) Which of the solutions would be used to relieve a stomach upset caused by indigestion? (b) Which solution is likely to be:       (i) Dilute sulphuric acid?                   (ii) Sodium hydroxide solution? 5. Solid copper (II) oxide is a base although it does not turn litmus paper to blue. Explain  6. Below are the pH values of 4 types of medicine represented by letters P, Q, R and S MEDICINE pH VALUES P Q R S 7.0 5.0 8.0 6.0  a) It is not advisable to use S when a patient has indigestion .Explain  b) What is the role of chemistry in drug manufacture 7.


5. Solid copper (II) oxide is a base although it does not turn litmus paper to blue. Explain  6. Below are the pH values of 4 types of medicine represented by letters P, Q, R and S MEDICINE pH VALUES P Q R S 7.0 5.0 8.0 6.0  a) It is not advisable to use S when a patient has indigestion .Explain  b) What is the role of chemistry in drug manufacture 7. Explain why very little Carbon (IV) oxide gas is evolved when dilute sulphuric (VI) acid is added to   lead (II) carbonate 8 .State one commercial use of Calcium Oxide 9. The following data gives the pH values of some solutions Solution pH P Q R 14.0 6.8 2.5 (a) What colour change would occur in solution P on addition of two drops of                     phenolphthalein  indicator?


Below are the pH values of 4 types of medicine represented by letters P, Q, R and S MEDICINE pH VALUES P Q R S 7.0 5.0 8.0 6.0  a) It is not advisable to use S when a patient has indigestion .Explain  b) What is the role of chemistry in drug manufacture 7. Explain why very little Carbon (IV) oxide gas is evolved when dilute sulphuric (VI) acid is added to   lead (II) carbonate 8 .State one commercial use of Calcium Oxide 9. The following data gives the pH values of some solutions Solution pH P Q R 14.0 6.8 2.5 (a) What colour change would occur in solution P on addition of two drops of                     phenolphthalein  indicator? (b) State the pH value of a resulting solution when equal moles of solution P and R react 10. In an experiment, ammonia gas was prepared by heating ammonium salt with an alkali.


The following data gives the pH values of some solutions Solution pH P Q R 14.0 6.8 2.5 (a) What colour change would occur in solution P on addition of two drops of                     phenolphthalein  indicator? (b) State the pH value of a resulting solution when equal moles of solution P and R react 10. In an experiment, ammonia gas was prepared by heating ammonium salt with an alkali.            After drying, ammonia gas was collected at room temperature and pressure. (a) What is meant by the term alkali? (b) Explain using physical properties of the gas why ammonia is not collected by downward                    delivery 11. The table shows the colours obtained when some indicators are added to solutions:- Solution Blue litmus paper Indicator W Distilled water ………………….. Colourless Calcium hydroxide Blue Pink Nitric acid ………………………… Colourless (a) Complete the table by filling in the missing colours (b) Identify indicator W
12.


(b) Explain using physical properties of the gas why ammonia is not collected by downward                    delivery 11. The table shows the colours obtained when some indicators are added to solutions:- Solution Blue litmus paper Indicator W Distilled water ………………….. Colourless Calcium hydroxide Blue Pink Nitric acid ………………………… Colourless (a) Complete the table by filling in the missing colours (b) Identify indicator W
12. (a) Flower extracts can be used as Acid-base indicators. Give two limitations of such                  indicators (b) The diagram below shows spots of pure substances W, X, and Y on a chromatography                   paper.   Spot Z is that of a mixture After development W, X, and Y were found to have moved 9cm3, 4cm3 and 7cm3 respectively.


The table shows the colours obtained when some indicators are added to solutions:- Solution Blue litmus paper Indicator W Distilled water ………………….. Colourless Calcium hydroxide Blue Pink Nitric acid ………………………… Colourless (a) Complete the table by filling in the missing colours (b) Identify indicator W
12. (a) Flower extracts can be used as Acid-base indicators. Give two limitations of such                  indicators (b) The diagram below shows spots of pure substances W, X, and Y on a chromatography                   paper.   Spot Z is that of a mixture After development W, X, and Y were found to have moved 9cm3, 4cm3 and 7cm3 respectively. Z has separated into two spots which have moved 7cm3 and 9cm3:- On the diagram:-  I. Label the baseline and solvent front II. Show the position of all the spots after development III. Identify the substances present in mixture Z 13.


Colourless Calcium hydroxide Blue Pink Nitric acid ………………………… Colourless (a) Complete the table by filling in the missing colours (b) Identify indicator W
12. (a) Flower extracts can be used as Acid-base indicators. Give two limitations of such                  indicators (b) The diagram below shows spots of pure substances W, X, and Y on a chromatography                   paper.   Spot Z is that of a mixture After development W, X, and Y were found to have moved 9cm3, 4cm3 and 7cm3 respectively. Z has separated into two spots which have moved 7cm3 and 9cm3:- On the diagram:-  I. Label the baseline and solvent front II. Show the position of all the spots after development III. Identify the substances present in mixture Z 13. A beekeeper found that when stung by a bee, application of a little solution of sodium             hydrogen carbonate helped to relieve the irritation of the affected area. Explain 14.


(a) Flower extracts can be used as Acid-base indicators. Give two limitations of such                  indicators (b) The diagram below shows spots of pure substances W, X, and Y on a chromatography                   paper.   Spot Z is that of a mixture After development W, X, and Y were found to have moved 9cm3, 4cm3 and 7cm3 respectively. Z has separated into two spots which have moved 7cm3 and 9cm3:- On the diagram:-  I. Label the baseline and solvent front II. Show the position of all the spots after development III. Identify the substances present in mixture Z 13. A beekeeper found that when stung by a bee, application of a little solution of sodium             hydrogen carbonate helped to relieve the irritation of the affected area. Explain 14. 10g of sodium hydrogen carbonate were dissolved in 20cm3 of water in a boiling tube.


Z has separated into two spots which have moved 7cm3 and 9cm3:- On the diagram:-  I. Label the baseline and solvent front II. Show the position of all the spots after development III. Identify the substances present in mixture Z 13. A beekeeper found that when stung by a bee, application of a little solution of sodium             hydrogen carbonate helped to relieve the irritation of the affected area. Explain 14. 10g of sodium hydrogen carbonate were dissolved in 20cm3 of water in a boiling tube. Lemon             juice was then added dropwise with shaking until there was no further change. (a) Explain the observation which was made in the boiling tube when the reaction was in progress (b) What observations would be made if the lemon juice had been added to copper turnings in                   a boiling tube? 15.


Lemon             juice was then added dropwise with shaking until there was no further change. (a) Explain the observation which was made in the boiling tube when the reaction was in progress (b) What observations would be made if the lemon juice had been added to copper turnings in                   a boiling tube? 15. (a) Complete the table below to show the colour of the given indicator in acidic and basic                   solutions: Indicator Colour in acidic solution Basic solution Methyl orange Pink Phenolphthalein Pink 16.       Solutions can be classified as acids, bases or neutral. The table below shows  solutions and their             pH values:- Solutions PH VALUES K L M 1.5 7.0 14.0
          (i) Select any pair that would react to form a solution of PH 7           (ii) Identify two solutions that would react with aluminium hydroxide. Explain Air and combustion 1.       The set-up below was used to prepare a sample of oxygen gas. Study it and answer            the questions that follow.


(a) Explain the observation which was made in the boiling tube when the reaction was in progress (b) What observations would be made if the lemon juice had been added to copper turnings in                   a boiling tube? 15. (a) Complete the table below to show the colour of the given indicator in acidic and basic                   solutions: Indicator Colour in acidic solution Basic solution Methyl orange Pink Phenolphthalein Pink 16.       Solutions can be classified as acids, bases or neutral. The table below shows  solutions and their             pH values:- Solutions PH VALUES K L M 1.5 7.0 14.0
          (i) Select any pair that would react to form a solution of PH 7           (ii) Identify two solutions that would react with aluminium hydroxide. Explain Air and combustion 1.       The set-up below was used to prepare a sample of oxygen gas. Study it and answer            the questions that follow.                   (i) Complete the diagram to show how Oxygen can be collected                  (ii) Write a chemical equation of the reaction to produce oxygen 2.


15. (a) Complete the table below to show the colour of the given indicator in acidic and basic                   solutions: Indicator Colour in acidic solution Basic solution Methyl orange Pink Phenolphthalein Pink 16.       Solutions can be classified as acids, bases or neutral. The table below shows  solutions and their             pH values:- Solutions PH VALUES K L M 1.5 7.0 14.0
          (i) Select any pair that would react to form a solution of PH 7           (ii) Identify two solutions that would react with aluminium hydroxide. Explain Air and combustion 1.       The set-up below was used to prepare a sample of oxygen gas. Study it and answer            the questions that follow.                   (i) Complete the diagram to show how Oxygen can be collected                  (ii) Write a chemical equation of the reaction to produce oxygen 2. Air was passed through several reagents as shown below: (a) Write an equation for the reaction which takes place in the chamber containing                    Magnesium powder (b) Name one gas which escapes from the chamber containing magnesium powder.


(a) Complete the table below to show the colour of the given indicator in acidic and basic                   solutions: Indicator Colour in acidic solution Basic solution Methyl orange Pink Phenolphthalein Pink 16.       Solutions can be classified as acids, bases or neutral. The table below shows  solutions and their             pH values:- Solutions PH VALUES K L M 1.5 7.0 14.0
          (i) Select any pair that would react to form a solution of PH 7           (ii) Identify two solutions that would react with aluminium hydroxide. Explain Air and combustion 1.       The set-up below was used to prepare a sample of oxygen gas. Study it and answer            the questions that follow.                   (i) Complete the diagram to show how Oxygen can be collected                  (ii) Write a chemical equation of the reaction to produce oxygen 2. Air was passed through several reagents as shown below: (a) Write an equation for the reaction which takes place in the chamber containing                    Magnesium powder (b) Name one gas which escapes from the chamber containing magnesium powder.                  Give a reason for your answer
3.


                  (i) Complete the diagram to show how Oxygen can be collected                  (ii) Write a chemical equation of the reaction to produce oxygen 2. Air was passed through several reagents as shown below: (a) Write an equation for the reaction which takes place in the chamber containing                    Magnesium powder (b) Name one gas which escapes from the chamber containing magnesium powder.                  Give a reason for your answer
3. (a) What is rust?


Air was passed through several reagents as shown below: (a) Write an equation for the reaction which takes place in the chamber containing                    Magnesium powder (b) Name one gas which escapes from the chamber containing magnesium powder.                  Give a reason for your answer
3. (a) What is rust? (b) Give two methods that can be used to prevent rusting (c) Name one substance which speeds up the rusting process 4.      3.0g of  clean  magnesium  ribbon 8.0g  of  clean  copper metal  were  burnt  separately  in            equal volume  of  air and  both metals  reacted completely  with  air;             a) State and explain where there was greater change in volume of air                  Mg =24   Cu = 64             b) Write an equation for the reaction between dilute sulphuric acid and product of burnt copper 5.        Oxygen is obtained on large scale by the fractional distillation of air as shown on the flow            chart bellow.


                 Give a reason for your answer
3. (a) What is rust? (b) Give two methods that can be used to prevent rusting (c) Name one substance which speeds up the rusting process 4.      3.0g of  clean  magnesium  ribbon 8.0g  of  clean  copper metal  were  burnt  separately  in            equal volume  of  air and  both metals  reacted completely  with  air;             a) State and explain where there was greater change in volume of air                  Mg =24   Cu = 64             b) Write an equation for the reaction between dilute sulphuric acid and product of burnt copper 5.        Oxygen is obtained on large scale by the fractional distillation of air as shown on the flow            chart bellow.          a) Identify the substance that is removed at the filtration stage          b) Explain why Carbon (IV) oxide and water are removed before liquefaction of air          c) Identify the component that is collected at -186°C 6.


(a) What is rust? (b) Give two methods that can be used to prevent rusting (c) Name one substance which speeds up the rusting process 4.      3.0g of  clean  magnesium  ribbon 8.0g  of  clean  copper metal  were  burnt  separately  in            equal volume  of  air and  both metals  reacted completely  with  air;             a) State and explain where there was greater change in volume of air                  Mg =24   Cu = 64             b) Write an equation for the reaction between dilute sulphuric acid and product of burnt copper 5.        Oxygen is obtained on large scale by the fractional distillation of air as shown on the flow            chart bellow.          a) Identify the substance that is removed at the filtration stage          b) Explain why Carbon (IV) oxide and water are removed before liquefaction of air          c) Identify the component that is collected at -186°C 6. The set-up below was used to study some properties of air.


(b) Give two methods that can be used to prevent rusting (c) Name one substance which speeds up the rusting process 4.      3.0g of  clean  magnesium  ribbon 8.0g  of  clean  copper metal  were  burnt  separately  in            equal volume  of  air and  both metals  reacted completely  with  air;             a) State and explain where there was greater change in volume of air                  Mg =24   Cu = 64             b) Write an equation for the reaction between dilute sulphuric acid and product of burnt copper 5.        Oxygen is obtained on large scale by the fractional distillation of air as shown on the flow            chart bellow.          a) Identify the substance that is removed at the filtration stage          b) Explain why Carbon (IV) oxide and water are removed before liquefaction of air          c) Identify the component that is collected at -186°C 6. The set-up below was used to study some properties of air. State and explain two observations that would be made at the end of the experiment
7.


         a) Identify the substance that is removed at the filtration stage          b) Explain why Carbon (IV) oxide and water are removed before liquefaction of air          c) Identify the component that is collected at -186°C 6. The set-up below was used to study some properties of air. State and explain two observations that would be made at the end of the experiment
7. A form two student in an attempt to stop rusting put copper and Zinc  in contact with iron             as shown:-       (a) State whether rusting occurred after one week if the set-ups were left out        (b) Explain your answer in (a) above 8. In an experiment, a piece of magnesium ribbon was cleaned with steel wool. 2.4g of             the clean magnesium ribbon was placed in a crucible and completely burnt in oxygen.


State and explain two observations that would be made at the end of the experiment
7. A form two student in an attempt to stop rusting put copper and Zinc  in contact with iron             as shown:-       (a) State whether rusting occurred after one week if the set-ups were left out        (b) Explain your answer in (a) above 8. In an experiment, a piece of magnesium ribbon was cleaned with steel wool. 2.4g of             the clean magnesium ribbon was placed in a crucible and completely burnt in oxygen.            After cooling the product weighed 4.0g a) Explain why it is necessary to clean magnesium ribbon b) What observation was made in the crucible after burning magnesium ribbon? c) Why was there an increase in mass?


In an experiment, a piece of magnesium ribbon was cleaned with steel wool. 2.4g of             the clean magnesium ribbon was placed in a crucible and completely burnt in oxygen.            After cooling the product weighed 4.0g a) Explain why it is necessary to clean magnesium ribbon b) What observation was made in the crucible after burning magnesium ribbon? c) Why was there an increase in mass? d) Write an equation for the major chemical reaction which took place in the crucible e) The product in the crucible was shaken with water and filtered. State and explain the                observation  which was made when red and blue litmus paper were dropped into the filtrate 9.       In an experiment a gas jar containing some damp iron fillings was inverted in a water trough           containing some water as shown in the diagram below. The set-up was left un-disturbed for three            days. Study it and answer the questions that follow: (a) Why were the iron filings moistened?


After cooling the product weighed 4.0g a) Explain why it is necessary to clean magnesium ribbon b) What observation was made in the crucible after burning magnesium ribbon? c) Why was there an increase in mass? d) Write an equation for the major chemical reaction which took place in the crucible e) The product in the crucible was shaken with water and filtered. State and explain the                observation  which was made when red and blue litmus paper were dropped into the filtrate 9.       In an experiment a gas jar containing some damp iron fillings was inverted in a water trough           containing some water as shown in the diagram below. The set-up was left un-disturbed for three            days. Study it and answer the questions that follow: (a) Why were the iron filings moistened? b) State and explain the observation made after three days.


c) Why was there an increase in mass? d) Write an equation for the major chemical reaction which took place in the crucible e) The product in the crucible was shaken with water and filtered. State and explain the                observation  which was made when red and blue litmus paper were dropped into the filtrate 9.       In an experiment a gas jar containing some damp iron fillings was inverted in a water trough           containing some water as shown in the diagram below. The set-up was left un-disturbed for three            days. Study it and answer the questions that follow: (a) Why were the iron filings moistened? b) State and explain the observation made after three days. (c) State two conclusions made from the experiment.


d) Write an equation for the major chemical reaction which took place in the crucible e) The product in the crucible was shaken with water and filtered. State and explain the                observation  which was made when red and blue litmus paper were dropped into the filtrate 9.       In an experiment a gas jar containing some damp iron fillings was inverted in a water trough           containing some water as shown in the diagram below. The set-up was left un-disturbed for three            days. Study it and answer the questions that follow: (a) Why were the iron filings moistened? b) State and explain the observation made after three days. (c) State two conclusions made from the experiment. d) Draw a labelled set-up of apparatus for the laboratory preparation of oxygen using                  Sodium Peroxide
(e) State two uses of oxygen 10.


b) State and explain the observation made after three days. (c) State two conclusions made from the experiment. d) Draw a labelled set-up of apparatus for the laboratory preparation of oxygen using                  Sodium Peroxide
(e) State two uses of oxygen 10.   In an experiment, a piece of magnesium ribbon was cleaned with steel wool. 2.4g of the clean                magnesium ribbon was placed in a crucible and completely burnt in oxygen. After cooling the                product weighed 4.0g a) Explain why it is necessary to clean magnesium ribbon b) What observation was made in the crucible after burning magnesium ribbon? c) Why was there an increase in mass?


d) Draw a labelled set-up of apparatus for the laboratory preparation of oxygen using                  Sodium Peroxide
(e) State two uses of oxygen 10.   In an experiment, a piece of magnesium ribbon was cleaned with steel wool. 2.4g of the clean                magnesium ribbon was placed in a crucible and completely burnt in oxygen. After cooling the                product weighed 4.0g a) Explain why it is necessary to clean magnesium ribbon b) What observation was made in the crucible after burning magnesium ribbon? c) Why was there an increase in mass? d) Write an equation for the major chemical reaction which took place in the crucible e) The product in the crucible was shaken with water and filtered. State and explain the                  observation  which was made when red and blue litmus paper were dropped into the filtrate 11.


In an experiment, a piece of magnesium ribbon was cleaned with steel wool. 2.4g of the clean                magnesium ribbon was placed in a crucible and completely burnt in oxygen. After cooling the                product weighed 4.0g a) Explain why it is necessary to clean magnesium ribbon b) What observation was made in the crucible after burning magnesium ribbon? c) Why was there an increase in mass? d) Write an equation for the major chemical reaction which took place in the crucible e) The product in the crucible was shaken with water and filtered. State and explain the                  observation  which was made when red and blue litmus paper were dropped into the filtrate 11.  The set-up below was used to collect gas F produced by the reaction between sodium peroxide and water water              (i) Name gas F…………………………………………………………………………… (ii) At the end of the experiment, the solution in the round bottomed flask was found to be                    a strong base. Explain why this was so (iii) Which property of gas F makes it be collected by the method used in the set-up?


c) Why was there an increase in mass? d) Write an equation for the major chemical reaction which took place in the crucible e) The product in the crucible was shaken with water and filtered. State and explain the                  observation  which was made when red and blue litmus paper were dropped into the filtrate 11.  The set-up below was used to collect gas F produced by the reaction between sodium peroxide and water water              (i) Name gas F…………………………………………………………………………… (ii) At the end of the experiment, the solution in the round bottomed flask was found to be                    a strong base. Explain why this was so (iii) Which property of gas F makes it be collected by the method used in the set-up? (iv) Give one industrial use of gas F 12. .


d) Write an equation for the major chemical reaction which took place in the crucible e) The product in the crucible was shaken with water and filtered. State and explain the                  observation  which was made when red and blue litmus paper were dropped into the filtrate 11.  The set-up below was used to collect gas F produced by the reaction between sodium peroxide and water water              (i) Name gas F…………………………………………………………………………… (ii) At the end of the experiment, the solution in the round bottomed flask was found to be                    a strong base. Explain why this was so (iii) Which property of gas F makes it be collected by the method used in the set-up? (iv) Give one industrial use of gas F 12. . The set-up below was used to investigate properties of the components of air:
(i) State two observations made during the experiment (ii) Write two chemical equations for the reactions which occurred (iii) The experiment was repeated using burning magnesium in place of phosphorous.


 The set-up below was used to collect gas F produced by the reaction between sodium peroxide and water water              (i) Name gas F…………………………………………………………………………… (ii) At the end of the experiment, the solution in the round bottomed flask was found to be                    a strong base. Explain why this was so (iii) Which property of gas F makes it be collected by the method used in the set-up? (iv) Give one industrial use of gas F 12. . The set-up below was used to investigate properties of the components of air:
(i) State two observations made during the experiment (ii) Write two chemical equations for the reactions which occurred (iii) The experiment was repeated using burning magnesium in place of phosphorous.       There was  greater rise of water than in the first case. Explain this observation (iv) After the two experiments, the water in each trough was tested using blue and red litmus              papers. State and explain the observations of each case.


(iv) Give one industrial use of gas F 12. . The set-up below was used to investigate properties of the components of air:
(i) State two observations made during the experiment (ii) Write two chemical equations for the reactions which occurred (iii) The experiment was repeated using burning magnesium in place of phosphorous.       There was  greater rise of water than in the first case. Explain this observation (iv) After the two experiments, the water in each trough was tested using blue and red litmus              papers. State and explain the observations of each case.          (a) Phosphorous experiment          b) magnesium experiment      (v) Briefly explain how a sample of nitrogen gas can be isolated from air in the laboratory 13. (a) A  group of students burnt a piece of Mg ribbon in air and its ash collected in a Petri dish.


There was  greater rise of water than in the first case. Explain this observation (iv) After the two experiments, the water in each trough was tested using blue and red litmus              papers. State and explain the observations of each case.          (a) Phosphorous experiment          b) magnesium experiment      (v) Briefly explain how a sample of nitrogen gas can be isolated from air in the laboratory 13. (a) A  group of students burnt a piece of Mg ribbon in air and its ash collected in a Petri dish.      The ash was found to comprise of magnesium Oxide and Magnesium nitride     (i) Write an equation for the reaction leading to formation of the magnesium nitride      (ii) A little water was added to the products in the Petri dish. State and explain the                        observation  made.


(a) Phosphorous experiment          b) magnesium experiment      (v) Briefly explain how a sample of nitrogen gas can be isolated from air in the laboratory 13. (a) A  group of students burnt a piece of Mg ribbon in air and its ash collected in a Petri dish.      The ash was found to comprise of magnesium Oxide and Magnesium nitride     (i) Write an equation for the reaction leading to formation of the magnesium nitride      (ii) A little water was added to the products in the Petri dish. State and explain the                        observation  made.     (iii) A piece of blue litmus paper was dipped into the solution formed in (b) above.           State the   observation made. 14.


(iii) A piece of blue litmus paper was dipped into the solution formed in (b) above.           State the   observation made. 14. A form one class carried out an experiment to determine the active part of air. The diagram             below shows the set-up of the experiment and also the observation made.         (i) At the beginning (ii) observation at the end of the experiment     (a) (i) Identify substance M..................................................................................


14. A form one class carried out an experiment to determine the active part of air. The diagram             below shows the set-up of the experiment and also the observation made.         (i) At the beginning (ii) observation at the end of the experiment     (a) (i) Identify substance M..................................................................................         (ii) State two reasons for the suitability of substance M for this experiment     (b) Write the equation for the reaction of substance M and the active part of air
    (c) (i) Using the letters Y and X write an expression for the percentage of the active part of air         (ii) The expression in (c)(i) above gives lower value than the expected. Explain      (d) (i) Explain the observation made when litmus paper is dipped into the beaker at the end of the               experiment           (ii) Name the active part of air ................................................................................................


A form one class carried out an experiment to determine the active part of air. The diagram             below shows the set-up of the experiment and also the observation made.         (i) At the beginning (ii) observation at the end of the experiment     (a) (i) Identify substance M..................................................................................         (ii) State two reasons for the suitability of substance M for this experiment     (b) Write the equation for the reaction of substance M and the active part of air
    (c) (i) Using the letters Y and X write an expression for the percentage of the active part of air         (ii) The expression in (c)(i) above gives lower value than the expected. Explain      (d) (i) Explain the observation made when litmus paper is dipped into the beaker at the end of the               experiment           (ii) Name the active part of air ................................................................................................            (iii) Suggest another method that can be used to determine the active part of air   15.