Examination for all levels, Essays (high school) of Business

Download Examination for all levels and more Essays (high school) Business in PDF only on Docsity!

[email protected]

Formoree-learningresourcescall 0795491185

FORM 3 TRIALEXAMS 2021

CHEMISTRY

Formarkingschemescall

MrMachuki 0795491185

ThisPDFcontainsafullset

paper.

Name:……………………………………………………… Adm No.…………………………… Class:……………………………………………………. Date:…............................................ 233 / 1 CHEMISTRY PAPER 1 FORM III TERM 3 EXAMS 2021 Time: 2 hours

CHEMISTRY

FORM III

INSTRUCTIONSTOTHECANDIDATES:-

 Writeyournameandadmissionnumberonthespacesprovided.  Answer allthequestionsinthespacesprovided.  Mathematicaltablesandelectronicusedcalculatorsmaybe  AllworkingMUSTbeclearlyshownwherenecessary.

Question Maximum score Candidate’sscore

1 - 30 80

Theaboveset-upwasusedtodeterminethechemicalpropertiesofcarbon(II)oxide. (a) Writethechemicalequationforthereactiontakingplaceinthecombustion tube. ( 1 mark) ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..

(b) Stateandexplaintheobservationmadeintheboilingtube. ( 2 marks) ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..

6. Astudentplacedsomehydrogenperoxideinatesttubethenaddedasmallamountof Solutionscanbeclassifiedasacids,basesorneutral.Thetablebelowshows solutionsandtheirpHvalues Solution pH–values

K 1. 5

L 7. 0

M 14. 0

(a)Selectanypairthatwouldreacttoform asolutionofpH 7 ( 1 Mark) …………………………………………………………… (b)Identifytwosolutionsthatwouldreactwithaluminium hydroxide.Explain ( 2 Marks) ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………… ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..

7. 9. 12 gofagaseouscompoundcontains 8 gofsiliconwhiletherestishydrogen.

Dry CO

Heat Boilingtube

Distilledwater+ universalindicator

Determinetheempiricalformulaofthecompound.(H= 1 ,Si= 28 ) ( 3 Marks) ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………… ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………

8. Studytheset-upbelowandanswerthequestionsthatfollow.

(a)Whyisaqueousammoniawarmedgently? ( 1 Mark) …………………………………………………………………………………………………………… (b) Whatisthecolouroftheflame? ( 1 Mark) ……………………………………………………………………………………………………….. (c)Writethechemicalequationforthereactionthattakesplace ( 1 Mark) ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………….. 9 .(a)Chlorinecanbepreparedinthelaboratorybyusingthefollowingreagentsand chemicals. Concentratedsulphuric(VI)acid,water,manganese(IV)oxide,concentrated hydrochloricacid. (i) Statetheroleofconcentratedsulphuric(VI)acid. ( 1 mark) …………………………………………………………………………………………………………

(ii) Writetheequationforformationofchlorine. ( 1 mark) ………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………

(iii) Whatistheroleofmanganese(IV)oxide? ( 1 mark) …………………………………………………………………………………………………………….

Flam

Oxygen

Glasstube Glasswool

Gentle

Aqueous ammonia

indicator. ( 1 mark) ……………………………………………………………………………………………………………………………………………………… …………………………………………………………………

(b) Threedropsoflitmussolutionwasaddedto 20 cm^3 of 2 M hydrochloricacidin abeakerfollowedby 20 cm^3 of 2 M ammonium hydroxide.Stateandexplain theobservationmade. ( 2 marks) ……………………………………………………………………………………………………………………………………………………… …………………………………………………………………

14. Studytheflowchartbelowandanswerthequestionsthatfollow.

(a) Identifysolid G………………………………………………………………… ( 1 mk)

……………………………………………………………………….

(a) Writeabalanced chemicalequationbetweentheyellowsolidanddilutenitric acid. ( 1 mk) ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..

15. Studythediagram belowandanswerthequestionsthatfollow.

(a) Definetheterm electrolysis. ( 1 mark) …………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………

MoltenMagnesium Chloride

Heat

(b) Onthediagram,labeltheAnodeandCathode. ( 2 marks)

(c) Writetheequationattheanode. ( 1 mark) ……………………………………………………………………………………………………………………………...

16. Inordertofindtheproportionbyvolumeofgasesinair,asampleofairwaspassed throughtwowashbottles,thefirstcontainingsodium hydroxidesolutionandthe secondcontainingconcentratedsulphuric(VI)acid.Theremaininggaswasthen collectedinasyringe. (a) Whywastheairpassedthrough; (i) sodium hydroxidesolution? ( 1 mark) ………………………………………………………………………….. (ii) concentratedsulphuric(VI)acid? ( 1 mark) …………………………………………………………………………… (b) Nameisthemajorgascollectedinthesyringe. ( 1 mark) ………………………………………………………………………………………..
17. Duringthemanufactureofsodium carbonateintheindustry. (a) Givethenameoftheprocesstomanufacturesodium carbonate. ( 1 mark) …………………………………………………………………………………………..

(b) Writethefinalequationtoform sodium carbonateduringtheprocess. ( 1 mark) ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………

(c) Giveoneuseofsodium carbonate. ( 1 mark) ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..

18 .Describehowtopreparecrystalofmagnesium sulphatestartingwithmagnesium powder.( 3 mks) ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………..

19. (a) Completethediagram belowtoshowhowdrysampleofhydrogengasis preparedinthe laboratory. ( 2 marks)

22. If 25 cm^3 of 0. 1 M H 2 SO 4 solutionneutralizedasolutioncontain 1. 06 gofsodium carbonatein 250 cm^3 ofsolution,calculatethemoralityandvolumeofsodium carbonatesolution. (Na= 23 ,O= 16 ,C= 12 ) ( 3 Marks) ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..
23. 50 cm^3 ofoxygengasdiffusedthroughaporousplugin 80 seconds.Howlongwillit take 100 cm^3 ofsulphur(IV)oxidetodiffusethroughthesameplug?(S= 32 ,o= 16 ) ( 3 Marks) ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..

24 .(a)Statetheroleofthefollowingpartsduringfractionaldistillationofamixtureofwater and ethanol (i)Glassbeadsinthefractionatingcolumn ( 1 Mark) ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………….. (ii)Fractionatingcolumn ( 1 Mark) ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………….. (b)Stateanyoneapplicationoffractionaldistillation ( 1 Mark) ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..

25. (a) State whatis observed when sodium hydroxide pellets are leftin air overnight.( 1 mark) ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………….. . (b) Whatnameisgiventheprocessshownbythesaltin(a)above? ( 1 mark) ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..

26. Given;

(a) Identify; SolidF - …………………………………………………………………………. ( 1 mark) SolidJ-…………………………………………………………………………… ( 1 mark) (b) Writeequationforstep 1. ( 1 mark) ………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………

27. Usedot()andcross(X)toshowthebondinginLithium oxide. ( 2 mark) ……………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..

28. Excessmagnesium ribbonwasburntinairtoform awhitesolidmixture.Writetwo equationstoshowtheformationofthewhitesolidmixture. ( 2 marks)

……………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………..

29 .Theset-upbelowshowshowgasAwaspreparedandreactedwithheatedmagnesium

SolidF

Blacksolid Kresidue BluesolutionJ

Colourlessgaswhichforms whiteprecipitatewithlime water.

Heat Step 1

Step 2 Add

Name:……………………………………………………… Adm No.……………………………

Class:……………………………………………………. Date:…............................................

233 / 2 CHEMISTRY PAPER 2 FORM III TERM 3 EXAMS 2021 Time: 2 hours

ANESTARSCHOOLSJOINTEXAMINATIONS 2021

CHEMISTRY

FORM III

INSTRUCTIONSTOTHECANDIDATES:-

 Writeyournameandadmissionnumberonthespacesprovided.  Answer allthequestionsinthespacesprovided.  Mathematicaltablesandelectronicusedcalculatorsmaybe  AllworkingMUSTbeclearlyshownwherenecessary.

QUESTION MAXIMUM SCORE CANDIDATE’SSCORE

1 - 30 80

1 .Thefigurebelowrepresentsasectionoftheperiodictable.Studyitandanswerquestions(a)to(h). Notethatthelettersdonotrepresenttheactualsymbolsoftheelements.

(a)ConsiderelementsD.HandI i)Givethechemicalfamilyoftheseelements. ( 1 mk)

---

ii)Howdotheirionicsizecompare. ( 1 mk)

---

iii)Compareandexplainthereactivityofthethreeelements. ( 2 mks)

---

---

b)Writetheelectronicconfigurationof; i)ElementH ( 1 mk)

---

ii)TheionofelementG. ( 1 mk)

---

c)Amoleculeofoneoftheelementsisshownbelow. ( 2 mks)

i)Identifythiselementfrom thesectionoftheperiodictableandgiveitsactualsymbolandname. ( 2 mks)

---

---

ii)Explainwhythiselementhasahigherboilingpointcomparedtothatofoxygen. ( 2 mks)

---

---

iii)Writeanequationtoshowthereactionbetweentheelementnamedabovewithoxygen. ( 1 mk)

---

iv) PredictthepHoftheoxideoftheaboveelementwheninwater.Explain. ( 2 mks)

i)NameliquidX ( 1 mk)

---

ii)SuggestthepHofthesolutioninconicalflaskK.Explain ( 2 mks)

---

---

iii)WriteanequationforthereactiontakingplaceintheconicalflaskM. ( 1 mk)

---

b)Stateandexplainthetwoobservationsmadewhenhydrogensulphideisbubbledintothesolution containingiron(III)chloride. ( 2 mks)

---

---

c) i)Describeasimplechemicaltestthatcanbeusedtodistinguishbetweencarbon(IV)oxideand carbon(II)oxidegases. ( 3 mks)

---

---

---

ii) Giveoneuseofcarbon(II)oxide. ( 1 mk)

---

d)Aform twostudentinvertedagasjarfullofcarbon(IV)oxideoverwaterandsodium hydroxide solution asshownbelow.

Explaintheobservationsmade. ( 2 mks)

---

---

4. (a)Namethetwocrystallineformsofsulphur ( 1 Mark)

(b)Theschemebelowrepresentsthestepsfollowedinthecontactprocess.Studyitand answer thequestionsthatfollow:-

(i)Nameoneimpurityremovedbythepurifier. ( 1 mark)

……………………………………………………………………………………………………………………………………………………………………

(ii)Whyisitnecessarytoremoveimpurities? ( 1 mark)

……………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………..

(iii)Writedowntheequationofthereactiontakingplaceintheconverter ( 1 mark)

……………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………..

(iv)Namethetwocatalyststhatcanbeusedintheconverter ( 2 marks)

Burner

SO 2

Air Purifier

DrySO 2 andair

Heatexchanger Absorption Cooler Tower

SO 3

Diluter Catalytic converter

SO 3 SO 2

Air

Oleum

Conc.H 2 SO 4

Conc.H 2 SO 4

SolidA Air

( 2 mks) Chamber 4

---

Chamber 5

---

(d) Nameonesourceofcheapcarbon(IV)oxideforSolvayprocess. ( 1 mk)

---

6 .a)Astudentsetuptheapparatusasshowninthediagram belowtoprepareandcollectdry ammoniagas.

i)Identifythreemistakesinthesetupandgiveareasonwhyeachismistake. ( 3 mks)

---

---

---

ii)Nameasuitabledryingagentforammonia. ( 1 mk)

---

iii)Writeanequationforthereactionthatoccurredwhenamixtureofammonium chlorideandcalcium hydroxidewasheated. ( 1 mk)

---

iv)Describeonechemicaltestforammoniagas. ( 1 mk)

---

b)Ammoniagasisusedtomanufacturenitric(V)acidasshownbelow.

i)Thisprocessrequirestheuseofacatalyst.Inwhichunitisthecatalystused? ( 1 mk)

---

ii)IdentifycompoundXandY. ( 2 mks)

---

---

iii)Ammoniareactswithnitric(v)acidtoform ammonium nitratefertilizer.Calculatethepercentage compositionofnitrogeninammonium nitrate.(N= 14 ,O= 16 ,H= 1 ) ( 3 marks)

---

---

7 .a) StateGraham’sLaw. ( 2 mks)

---

---

---

b) Thetablebelowshowstherelationshipbetweenthepressureandvolumeofafixedmassof ozonegas. Pressure(Kpa) 1 4 8 16 20 160 Volume(cm^3 ) 140 40 20 10 8 1 Inverseofvolume 1 /v(cm-^3 )