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(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.​ ​ ​...
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Z​ ​has​ ​separated​ ​into​ ​two​ ​spots​ ​which​ ​have​ ​moved​ ​7cm​3​​ ​and​ ​9cm​3​:- 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​ ​beekeep...
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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​ ​l...
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(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)​ ​Comp...
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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​ ​cla...
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(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​ ​classif...
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​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(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)​ ​W...
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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​ ​ma...
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​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​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....
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(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​ ​ ​i...
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(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 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ...
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​ ​ ​ ​ ​ ​ ​ ​ ​ ​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...
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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​ ​rusti...
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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)...
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​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​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​ ​equa...
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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 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​obse...
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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​ ​...
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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...
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d)​ ​Draw​ ​a​ ​labelled​ ​set-up​ ​of​ ​apparatus​ ​for​ ​the​ ​laboratory​ ​preparation​ ​of​ ​oxygen​ ​using ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​Sodium​ ​Peroxide (e)​ ​State​ ​t​wo​ ​uses​ ​of​ ​oxygen 10. ​ ​ ​In​ ​an​ ​experiment,​ ​a​ ​piece​ ​of​ ​magnesium​ ​ribbon​ ​was​ ​cleaned​ ​with​ ​steel​ ​wool.​ ​2.4g​...
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​ ​ ​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​ ​we...
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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 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​...
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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​ ​an...
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​ ​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​ ​w...
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(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)...
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​ ​ ​ ​ ​ ​ ​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​ ​observa...
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​ ​ ​ ​ ​ ​ ​ ​ ​ ​(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​...
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​ ​ ​ ​ ​(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 ​ ​ ​ ​ ​ ​...
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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​ ​e...
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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​ ...
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​ ​ ​ ​ ​ ​ ​ ​ ​(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​ ...
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​ ​ ​ ​ ​ ​ ​ ​ ​(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​ ​expressi...
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​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(iii)​ ​Suggest​ ​another​ ​method​ ​that​ ​can​ ​be​ ​used​ ​to​ ​determine​ ​the​ ​active​ ​part​ ​of​ ​air ​ ​ ​15. A​ ​piece​ ​of​ ​phosphorous​ ​was​ ​burnt​ ​in​ ​excess​ ​air.​ ​The​ ​product​ ​obtained​ ​was​ ​shaken​ ​with​ ​a small ​ ​amount​ ​of​ ​hot​ ​water​ ​to​ ​make​ ​a​ ​solution...
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A​ ​piece​ ​of​ ​phosphorous​ ​was​ ​burnt​ ​in​ ​excess​ ​air.​ ​The​ ​product​ ​obtained​ ​was​ ​shaken​ ​with​ ​a small ​ ​amount​ ​of​ ​hot​ ​water​ ​to​ ​make​ ​a​ ​solution ​ ​ ​ ​ ​i)​ ​Write​ ​an​ ​equation​ ​for​ ​the​ ​burning​ ​of​ ​phosphorus​ ​in​ ​excess​ ​air ​ ​ ​ ​ ​ii)​ ​The​ ​solution​ ​obtained​ ​in...
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Study​ ​the​ ​set-up​ ​below​ ​and​ ​answer​ ​the​ ​questions​ ​that​ ​follow:- (a)​ ​State​ ​two​ ​observations​ ​that​ ​would​ ​be​ ​made​ ​after​ ​one​ ​week.​ ​Explain (b)​ ​Write​ ​the​ ​equation​ ​of​ ​the​ ​reaction​ ​taking​ ​place​ ​in​ ​the​ ​test-tube 17. Fe​3​O​4​​ ​and​ ​FeO​ ​are​ ​oxides​ ​of​ ​iron​ ​wh...
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b)​ ​A​ ​highly​ ​water​ ​soluble​ ​basic​ ​oxide. c)​ ​An​ ​oxide​ ​which​ ​can​ ​react​ ​with​ ​both​ ​sodium​ ​hydroxide​ ​solution​ ​and​ ​dilute​ ​hydrochloric acid. 19. The​ ​diagram​ ​below​ ​shows​ ​students​ ​set-up​ ​for​ ​the​ ​preparation​ ​and​ ​collection​ ​of​ ​oxygen gas (a)​ ​Name​ ​substance​ ​X​ ​use...
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(a)​ ​Hydrogen​ ​can​ ​reduce​ ​coppers​ ​Oxide​ ​but​ ​not​ ​alluminium​ ​oxide.​ ​Explain (b)​ ​When​ ​water​ ​reacts​ ​with​ ​potassium​ ​metal​ ​the​ ​hydrogen​ ​produced​ ​ignites​ ​explosively ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​on​ ​the​ ​surface​ ​of​ ​water. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(i)​ ​What...
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​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(ii)​ ​Write​ ​an​ ​equation​ ​to​ ​show​ ​how​ ​this​ ​ignition​ ​occurs 2. In​ ​an experiment,​ ​dry​ ​hydrogen​ ​gas​ ​was​ ​passed​ ​over​ ​hot​ ​copper​ ​(II)​ ​oxide​ ​in​ ​a​ ​combustion ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​tube​ ​as​ ​ ​shown​ ​in​ ​the​ ​diagram​ ​below:- (a)​ ​Compl...
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​ ​ ​ ​ ​(b)​ ​Write​ ​a​ ​chemical​ ​equation​ ​for​ ​the​ ​reaction​ ​that​ ​produces​ ​the​ ​flame. 4. Gas​ ​P​ ​was​ ​passed​ ​over​ ​heated​ ​magnesium​ ​ribbon​ ​and​ ​hydrogen​ ​gas​ ​was​ ​collected​ ​as shown in the​ ​diagram​ ​below: (i)​ ​Name​ ​gas​ ​P ..........................................................
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(ii)​ ​Write​ ​an​ ​equation​ ​of​ ​the​ ​reaction​ ​that​ ​takes​ ​place​ ​in​ ​the​ ​combustion​ ​tube (iii)​ ​State​ ​one​ ​precaution​ ​necessary​ ​at​ ​the​ ​end​ ​of​ ​this​ ​experiment 5.​ ​ ​ ​ ​ ​ ​ ​When​ ​hydrogen​ ​is​ ​burnt​ ​and​ ​the​ ​product​ ​cooled,​ ​the​ ​following​ ​results​ ​are​ ​obtained​ ​as ...
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7. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​(a)​ ​Between​ ​N​ ​and​ ​M​ ​which​ ​part​ ​should​ ​be​ ​heated​ ​first?​ ​Explain (b)​ ​Write​ ​a​ ​chemical​ ​equation​ ​for​ ​the​ ​reaction​ ​occurring​ ​in​ ​the​ ​combustion​ ​tube. 8. The​ ​set-up​ ​below​ ​was​ ​used​ ​to​ ​investigate​ ​electrolysis​ ​of​ ​a​ ​certain​ ​molten​ ​com...
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c)​ ​Explain​ ​why​ ​copper​ ​metal​ ​cannot​ ​be​ ​used​ ​to​ ​prepare​ ​hydrogen​ ​gas. d)​ ​Hydrogen​ ​burns​ ​in​ ​oxygen​ ​to​ ​form​ ​an​ ​oxide. ​ ​ ​ ​(i)​ ​Write​ ​an​ ​equation​ ​for​ ​the​ ​reaction. ​ ​ ​ ​(ii)​ ​State​ ​two​ ​precautions​ ​that​ ​must​ ​be​ ​taken​ ​before​ ​the​ ​combustion​ ​begins​ ​and...
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h)​ ​Explain​ ​how​ ​hydrogen​ ​is​ ​used​ ​in​ ​the​ ​manufacture​ ​of​ ​margarine. 10. a)​ ​The​ ​set-up​ ​below​ ​ ​is​ ​used​ ​to​ ​investigate​ ​the​ ​properties​ ​ ​of​ ​ ​hydrogen. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​i)​ ​On​ ​the​ ​diagram,​ ​indicate​ ​what​ ​should​ ​be​ ​done​ ​for​ ​the​ ​reaction​ ​to​ ​occur ​ ​ ​ ​ ​ ​...
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​ ​ ​ ​ ​ ​ ​ ​ ​vi)​ ​What​ ​observation​ ​confirms​ ​the​ ​property​ ​stated​ ​in​ ​(​v)​ ​above? ​ ​ ​ ​ ​ ​ ​ ​ ​vii)​ ​Why​ ​is​ ​zinc​ ​oxide​ ​not​ ​used​ ​to​ ​investigate​ ​this​ ​property​ ​of​ ​hydrogen​ ​gas? 11. The​ ​set​ ​up​ ​below​ ​was​ ​used​ ​to​ ​collect​ ​gas​ ​K,​ ​produced​ ​by​ ​the​ ​reacti...
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ATOMIC STRUCTURE AND THE PERIODIC TABLE Preface The structure of the atom is extensively covered here. The periodic table is the arrangement of atoms of elements based on their atomic structure. Emphasis on the trends across and down the periodic table of atoms is important for the teacher facilitator. This work should...
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Candidate-user preparing for any secondary level chemistry from members of A.ATOMIC STRUCTURE The atom is the smallest particle of an element that take part in a chemical reaction.The atom is made up of three subatomic particle: (i)Protons (ii)Electrons (iii)Neutrons (i)Protons 1.The proton is positively charged 2.Is f...
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3.It has a relative mass 1/1840 4.The number of protons and electrons in a atom of an element is always equal (iii)Neutrons 1.The Neutron is neither positively or negatively charged thus neutral. 2.Like protons it is found in the centre of an atom called nucleus 3.It has a relative mass 1 4.The number of protons and ne...
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Isotopes are atoms of the same element, having the same number of protons/atomic number but different number of neutrons/mass number. By convention, isotopes are written with the mass number as superscript and the atomic number as subscript to the left of the chemical symbol of the element. i.e. mass number atomic numb...
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i.e. mass number atomic number m n X symbol of element Below is the conventional method of writing the 1st twenty elements showing the mass numbers and atomic numbers; 2He 4Be 6C 147N 168O 10Ne 12Mg 14Si 16S 18Ar 20C The table below shows some common natural isotopes of some elements Element Isotopes Protons Electrons ...
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All other atoms are compared to the mass of 12C isotope to give the relative at The relative atomic mass(RAM) is therefore defined as “the mass of average atom of an element compared to 1/12 an atom of 12C isotope whose mass is arbitrarily fixed as 12.000 atomic mass units(a.m.u) ” i.e; RAM = mass of atom of an element...
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Calculate the relative atomic mass of Chlorine. Working 100 atoms of chlorine contains 75 atoms of 3517Cl isotopes 100 atoms of chlorine contains 75 atoms of 3717Cl isotopes Therefore; RAM of chlorine = ( 75/100 x 35) + 25/100 x 37 = 35.5 Note that: Relative atomic mass has no units More atoms of chlorine exist as 3517...
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Working 100 atoms of chlorine contains 75 atoms of 3517Cl isotopes 100 atoms of chlorine contains 75 atoms of 3717Cl isotopes Therefore; RAM of chlorine = ( 75/100 x 35) + 25/100 x 37 = 35.5 Note that: Relative atomic mass has no units More atoms of chlorine exist as 3517Cl(75%) than as 3717Cl(25%) therefore RAM is nea...
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b) Calculate the relative atomic mass of potassium given that it exist as; 5 93.1% 3919K , 0.01% 4019K , 6.89% 4119K , Working 100 atoms of potassium contains 93.1 atoms of 3919K isotopes 100 atoms of potassium contains 0.01 atoms of 4019K isotopes 100 atoms of potassium contains 6.89 atoms of 4119K isotopes Therefore;...
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Electrons are found in energy levels/orbital. An energy level is a fixed region around/surrounding the nucleus of an atom occupied by electrons of the same (potential) energy. By convention energy levels are named 1,2,3… outwards from the region nearest to nucleus. Each energy level is occupied by a fixed number of ele...
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An energy level is a fixed region around/surrounding the nucleus of an atom occupied by electrons of the same (potential) energy. By convention energy levels are named 1,2,3… outwards from the region nearest to nucleus. Each energy level is occupied by a fixed number of electrons: The 1st energy level is occupied by a ...
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By convention energy levels are named 1,2,3… outwards from the region nearest to nucleus. Each energy level is occupied by a fixed number of electrons: The 1st energy level is occupied by a maximum of two electrons 6 The 2nd energy level is occupied by a maximum of eight electrons The 3rd energy level is occupied by a ...
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Each energy level is occupied by a fixed number of electrons: The 1st energy level is occupied by a maximum of two electrons 6 The 2nd energy level is occupied by a maximum of eight electrons The 3rd energy level is occupied by a maximum of eight electrons( or eighteen electrons if available) The 4th energy level is oc...
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By convention the electron configuration / structure of an atom of an element can be shown in form of a diagram using either cross(x) or dot(●) to Practice examples drawing electronic configurations a)11H has - in nucleus1proton and 0 neutrons - 1 electron in the 1st energy levels thus: Nucleus Energy levels Electrons(...
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Scientists have tried to group them together in a periodic table. A periodic table is a horizontal and vertical arrangement of elements according to their atomic numbers. This table was successfully arranged in 1913 by the British scientist Henry Moseley from the previous work of the Russian Scientist Dmitri Mendeleev....
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When an atom has no maximum number of electrons in its outer energy level, it is said to be unstable. All stable atoms are in group 8/18 of the periodic table. All other elements are unstable. THE STANDARD PERIODIC TABLE OF ELEMENTS 14 All unstable atoms/isotopes try to be stable through chemical reactions. A chemical ...
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Except Hydrogen The charge carried by an ion is equal to the number of electrons gained/acquired or donated/lost. Examples of ion formation 1.11H H -> H+ + e (atom) (monovalent cation) (electrons donated/lost) Electronic configuration 1: (No electrons remains) 15 2. 2713 Al Al -> Al3+ + 3e (atom) (trivalent cation) (3 ...
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199F F + e -> F- (atom) ( 1 electrons gained/acquired) (anion) Electron 2:7 2:8 structure (unstable) (stable) 9. 3517Cl 16 Cl + e -> Cl- (atom) ( 1 electrons gained/acquired) (anion) Electron 2:8:7 2:8:8 structure (unstable) (stable) 3. 3919 K K -> K+ + e (atom) (cation) ( 1 electrons donated/lost) Electron 2:8:8:1 2:8...
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When an element acquires/gains extra electrons in its outer energy level,the process is called reduction.The charge carried by an atom, cation or anion is its oxidation state. Table showing the oxidation states of some isotopes Element Symbol of element / isotopes Charge of ion Oxidation state Hydrogen 1H(deuterium) 31...
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Table showing the oxidation states of some isotopes Element Symbol of element / isotopes Charge of ion Oxidation state Hydrogen 1H(deuterium) 31H(Tritium) H+ H+ H+ +1 +1 +1 Chlorine 17Cl Cl- Cl- -1 -1 Potassium 19K 4119K K+ K+ K+ +1 +1 +1 Oxygen 8O O2- O2- -2 -2 Magnesium 2412Mg Mg2+ +2 sodium 2311Na Na+ +1 Copper Cu C...
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Roman capital numeral is used to indicate the oxidation state of an element with a variable oxidation state in a compound. Examples: (i) Copper (I) means Cu+ as in Copper(I)oxide (ii) Copper (II) means Cu2+ as in Copper(II)oxide (iii) Iron (II) means Fe2+ as in Iron(II)sulphide (iv) Iron (III) means Fe3+ as in Iron(III...
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(iii)electrons donated/lost by outer energy level of metals to be stable/attain octet/duplet. (iv)charges carried by ions/cations/ions 18 Group of atoms that react as a unit during chemical reactions are called radicals.Elements with variable oxidation state also have more than one valency. Table showing the valency of...
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(iv)Interchange/exchange the valencies of each element as subscript. (v)Divide by the smallest/lowest valency to derive the smallest whole number ratios Ignore a valency of 1. This is the chemical formula. Practice examples Write the chemical formula of (a)Aluminium oxide Elements making compound Aluminium Oxygen Symbo...
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Practice examples Write the chemical formula of (a)Aluminium oxide Elements making compound Aluminium Oxygen Symbol of elements/radicals in compound Al O Assign valencies as superscript Al3 O2 Exchange/Interchange the valencies as subscript Al2 O3 Divide by smallest valency to get whole number - - Chemical formula of A...
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(d)Lead(IV)oxide Elements making compound Lead Oxygen Symbol of elements/radicals in compound Pb O Assign valencies as superscript Pb4 O2 Exchange/Interchange the valencies as subscript Pb2 O4 Divide by two to get smallest whole number ratio Pb1 O2 Chemical formula of Lead(IV) oxide is thus: PbO2 This means:1 atom of l...
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(e)Iron(III)oxide Elements making compound Iron Oxygen Symbol of elements/radicals in compound Fe O Assign valencies as superscript Fe3 O2 Exchange/Interchange the valencies as subscript Fe2 O3 Divide by two to get smallest whole number ratio - - Chemical formula of Iron(III) oxide is thus: Fe2O3 This means:2 atom of l...
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(f)Iron(II)sulphate(VI) Elements making compound Iron sulphate(VI) Symbol of elements/radicals in compound Fe SO4 Assign valencies as superscript Fe2 SO4 2 Exchange/Interchange the valencies as subscript Fe2 SO4 2 Divide by two to get smallest whole number ratio Fe1 SO4 1 21 Chemical formula of Iron(II) sulphate(VI) is...
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(g)Copper(II)sulphate(VI) Elements making compound Copper sulphate(VI) Symbol of elements/radicals in compound Cu SO4 Assign valencies as superscript Cu2 SO4 2 Exchange/Interchange the valencies as subscript Cu2 SO4 2 Divide by two to get smallest whole number ratio Cu1 SO4 1 Chemical formula of Cu(II)sulphate(VI) is t...
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(h)Aluminium sulphate(VI) Elements making compound Aluminium sulphate(VI) Symbol of elements/radicals in compound Al SO4 Assign valencies as superscript Al3 SO4 2 Exchange/Interchange the valencies as subscript Al2 SO4 3 Divide by two to get smallest whole number ratio - - Chemical formula of Aluminium sulphate(VI) is ...
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(i)Aluminium nitrate(V) Elements making compound Aluminium nitrate(V) Symbol of elements/radicals in compound Al NO3 Assign valencies as superscript Al3 NO3 1 Exchange/Interchange the valencies as subscript Al1 NO3 3 Divide by two to get smallest whole number ratio - - Chemical formula of Aluminium sulphate(VI) is thus...
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(j)Potassium manganate(VII) Elements making compound Potassium manganate(VII) Symbol of elements/radicals in compound K MnO4 Assign valencies as superscript K 1 MnO4 1 Exchange/Interchange the valencies as subscript K1 MnO4 1 Divide by two to get smallest whole number ratio - - 22 Chemical formula of Potassium manganat...
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A chemical reaction is a statement showing the movement of reactants to form products. The following procedure is used in writing a chemical equations: 23 1. Write the word equation 2. Write the correct chemical formula for each of the reactants and products 3. Check if the number of atoms of each element on the reacta...
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Zn + 2 HCl -> ZnCl2 + H2 5. Assign in brackets, the physical state/state symbols . Zn(s) + 2 HCl(aq) -> ZnCl2 (aq) + H2(g) 24 (b) Oxygen gas is prepared from decomposition of Hydrogen peroxide solution to water Procedure 1. Write the word equation Hydrogen peroxide -> Water + oxygen gas 2. Write the correct chemical fo...
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Write the word equation Potassium manganate(VII) + Hydrochloric acid -> potassium chloride + manganese(II) chloride + chlorine +water 2. Write the correct chemical formula for each of the reactants and products KMnO4 + HCl -> KCl + MnCl2 +H2O + Cl2 3. Check if the number of atoms of each element on the reactant side is...
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Write the correct chemical formula for each of the reactants and products CaCO3 + HCl -> CaCl2 +H2O + CO2 3. Check if the number of atoms of each element on the reactant side is equal to the number of atoms of each element on the product side. 4. Multiply the chemical formula containing the unbalanced atoms with the lo...
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2H2S(g) + 3O2(g) -> 2SO2(g) + 2H2O(l) (i)Magnesium reacts with steam to form Magnesium Oxide and Hydrogen gas. Mg(s) + 2H2O(g) -> MgO(s) + H2(g) (j)Ethane(C2H6) gas burns in air to form Carbon(IV)Oxide and water. 2C2H6(g) + 7O2(g) -> 4CO2(g) + 6H2O(l) (k)Ethene(C2H4) gas burns in air to form Carbon(IV)Oxide and water. ...
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Elements in the same group thus constitute a chemical family. (a) Group I elements: Alkali metals Group I elements are called Alkali metals except Hydrogen which is a non metal. The alkali metals include: Element Symbol Atomic number Electron structure Oxidation state Valency Lithium Li 3 2:1 Li+ 1 Sodium Na 11 2:8:1 N...
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Atomic radius and ionic radius of alkali metals increase down the group as the number of energy levels increases. The atomic radius of alkali metals is bigger than the ionic radius. This is because alkali metals react by losing/donating the outer electron and hence lose the outer energy level. Table showing the atomic ...
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e.g. The 1st ionization energy of sodium is 496 kJmole-1 while that of potassium is 419 kJmole-1 .This is because atomic radius increase and thus effective nuclear attraction on outer energy level electrons decrease down the group from sodium to Potassium. It requires therefore less energy to donate/lose outer electron...
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Example On exposure to air, Sodium first reacts with Oxygen to form sodium oxide. 4Na(s) + O2(g) -> 2Na2O(s) The sodium oxide formed further reacts with water/moisture in the air to form sodium hydroxide solution. 30 Na2O(s) + H2O(l) -> 2NaOH(aq) Sodium hydroxide solution reacts with carbon(IV)oxide in the air to form ...
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Put three drops of phenolphthalein indicator. Put about 0.5g of Lithium metal into the beaker. Determine the pH of final product Repeat the experiment using about 0.1 g of Sodium and Potassium. Caution: Keep a distance Observations Alkali metal Observations Comparative speed/rate of the reaction Lithium -Metal floats i...
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Potassium is more reactive than sodium .Sodium is more reactive than Lithium. The reactivity increases as electropositivity increases of the alkali increases. This is because as the atomic radius increases , the ease of donating/losing outer electron increase during chemical reactions. Chemical equations 2Li(s) + 2H2O(...
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32 Lithium metal continues to burn with a crimson flame forming white solid / fumes. Alkali metal react with chlorine gas to form the corresponding metal chlorides. The reactivity increase as electropositivity increase down the group from Lithium to Francium.The ease of donating/losing the outer electrons increase as t...
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(ii)Sodium chloride is used in seasoning food. (iii)Molten mixture of sodium and potassium is used as coolant in nuclear reactors. (iv)Sodium is used in making sodium hydroxide used in making soapy and soapless detergents. Lithium sodium Potassium Hydroxide LiOH NaOH KOH Oxide Li2O Na2O K2O Sulphide Li2S Na2S K2S Chlor...
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Group II elements: Alkaline earth metals Group II elements are called Alkaline earth metals . The alkaline earth metals include: Element Symbol Atomic number Electron structure Oxidation state Valency Beryllium Be 4 2:2 Be2+ 2 Magnesium Mg 12 2:8:2 Mg2+ 2 Calcium Ca 20 2:8:8:2 Ca2+ 2 Strontium Sr 38 2:8:18:8:2 Sr2+ 2 B...
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The remaining electrons/energy levels experience more effective / greater nuclear attraction/pull towards the nucleus reducing the atomic radius. Electropositivity All alkaline earth metals are also electropositive like alkali metals. The electropositivity increase with increase in atomic radius/size. Calcium is more e...
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Atomic radius of Sodium (0.157nM) is higher than that of Magnesium (0.137nM). This is because Magnesium has more effective nuclear attraction on 35 the outer energy level than Sodium hence pulls outer energy level more nearer to its nucleus. Physical properties Soft/Easy to cut: Alkaline earth metals are not soft and e...
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Electrical conductivity increase down the group as the atomic radius/size increase making the delocalized outer electrons less attracted to nucleus. Alkaline earth metals are better thermal and electrical conductors than alkali metals because they have more/two outer delocalized electrons.e.g. Magnesium is a better con...
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Swirl. Test the mixture using litmus papers. Repeat with Calcium Observations -Magnesium burns with a bright blindening flame -White solid /ash produced -Solid dissolves in water to form a colourless solution -Blue litmus paper remain blue -Red litmus paper turns blue -colourless gas with pungent smell of urine Explana...
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Repeat with Calcium metal. Observations -Surface of magnesium covered by bubbles of colourless gas. -Colourless solution formed. -Effervescence/bubbles/fizzing takes place in Calcium. -Red litmus paper turns blue. -Blue litmus paper remains blue. Explanations Magnesium slowly reacts with cold water to form Magnesium hy...
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-Pale green colour of chlorine fades. Explanation Magnesium continues to burn in chlorine gas forming white magnesium oxide solid. Mg(s) + Cl2 (g) -> MgCl2 (s) Calcium burns slightly in chlorine gas to form white calcium oxide solid. Calcium oxide formed coat unreacted Calcium stopping further reaction Ca(s) + Cl2 (g) ...
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Nitric(V)acid is a strong oxidizing agent. It quickly oxidizes the hydrogen produced to water. Calcium is very reactive with dilute acids and thus a very small piece of very dilute acid should be used. Chemical equations 40 Mg(s) + H2SO4 (aq) -> MgSO4(aq) + H2 (g) Mg(s) + 2HNO3 (aq) -> Mg(NO3)2(aq) + H2 (g) Mg(s) + 2HC...
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(iii)Making cement-Calcium carbonate is mixed with clay and sand then heated to form cement for construction/building. (iv)Raise soil pH-Quicklime/calcium oxide is added to acidic soils to neutralize and raise the soil pH in agricultural farms. (v)As nitrogenous fertilizer-Calcium nitrate(V) is used as an agricultural ...
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They therefore are therefore monovalent .They exist in oxidation state X- The number of energy levels increases down the group from Fluorine to Astatine. The more the number of energy levels the bigger/larger the atomic size. e.g. The atomic size/radius of Chlorine is bigger/larger than that of Fluorine because Chlorin...
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It is measured using Pauling’s scale. Where Fluorine with Pauling scale 4.0 is the most electronegative element and thus the highest tendency to acquire/gain extra electron. Table showing the electronegativity of the halogens. Halogen F Cl Br I At Electronegativity (Pauling scale) 4.0 3.0 2.8 2.5 2.2 The electronegativ...
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(ii) Electronegativity. -Electron affinity is the energy required to gain an electron in an atom of an element in gaseous state. It involves the process: X(g) + e -> X-(g) Electronegativity is the ease/tendency of gaining/ acquiring electrons by an element during chemical reactions. It does not involve use of energy bu...
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Solubility of halogens in non-polar solvent increase down the group. The level of water in chlorine is higher than in bromine and the level of tetrachloromethane in chlorine is lower than in bromine. Caution: Tetrachloromethane , Bromine vapour and Chlorine gas are all highly toxic/poisonous. Table showing the physical...
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