Chemistry paper two exam.

545/2 CHEMISTRY Paper2 December.2022
ENDOFYEAREXAMINATIONS2022 S.3CHEMISTRY
Paper2

INSTRUCTIONSTOCANDIDATES: SectionAconsistsof10structuredquestions.AnswerALLquestionsinthissection. Answerstothequestionsmustbewriteninthespacesprovided.
SectionBconsistsof4semi–structuredquestions.Answeronlytwoquestionsfrom thissection.Answerstothequestionsmustbewritenintheanswerbookletsprovided. Inbothsectionsalworkingmustbeshownclearly.
Wherenecessary
[Zn=65,O=16,H=1,Pb=207]
3 1moleofagasoccupies22.4dm ats.t.p
3 1moleofagasoccupies24dm atroomtemperature
ForExaminer’suseonly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 TOTAL
CHEMISTRYDEPARTMENT@2022 TurnOver

SECTIONA:(50MARKS) AnswerALLquestionsinthissection
1. AnatomofelementM has12protonsand13neutrons.
(a) (i) TowhichgroupoftheperiodictabledoesM belong? (1⁄2
mark)
.
(i) WhatistheatomicmassofelementM. (1⁄2mark)
.
(i) WhatistherelationshipbetweenelementM andN?(N has12 neutronsand12protons).
(1⁄2mark)
.
(b) Write;
(i) the form ula ofthe ion M form s m ost. (1⁄2 m ark)
.
(i) theformulaofthecompoundformedwhenM reactswithnitrogen gas.
(1⁄2mark)
.
(i) theequationforthereactionbetweenM andchlorinegas. (11⁄2 marks)
.
(c) State;
(i) thetypeofbondformedwhenM combineswithchlorine. (1⁄2
mark)
. .
(i) twopropertiesoftheproductformedwhenM combineswith chlorine.
(02marks)
2

.
2. (a) Amagnetwasrubbedthroughamixtureofsulphurandironfilings.State: (i) whatwasobserved.
(1⁄2mark)
.
(i) whatwouldbeobservedifthemixturewasheated? (01mark)
.
(b) Writeanequationforthereactionwhichtakesplacewhenthemixturein (a)isheated. (11⁄2 marks)
.
(c) Apartfrom usingamagnet,brieflyexplainhow sulphurcanbeobtained from themixture. (11⁄2 marks)
.
.
3. Dilute hydrochloric acid was added to zinc granules contained in a round bot tom ed flask connected to a U – tube containing anhydrous calcium chloride. (a) (i) Statetheroleofanhydrouscalcium chlorideinthisexperiment.
(01mark)
.
(i) WhatwouldbeobservedifanopeningwasmadeontheU–tube andaflameapplied?
(01mark)
.
(i) Writeanequationforthereactionwhichtakesplacein(a)(i)above. (11⁄2marks)
.
(b) Howcanyoutestfortheproductformedin(a)(i)? (01mark)
. .
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4. Amixtureofcopperturningsandconcentratednitricacidwasheatedinaround botomedflask.
(a) (i) Statewhatwasobserved. (11⁄2marks)
. .
(i) Writeanequationforthereaction. (11⁄2 marks)
.
(b) Statewhatwouldbeobservedifammoniasolutionwasaddedtothe resultantsolutiondropwiseuntilinexcess.
(11⁄2marks)
. .
5.(a)Chlorinecanbepreparedinthelaboratorybytheactionofmanganese(IV) oxideon
substanceQ.
(i) NamesubstanceQ (1⁄2mark)
……………………………………………………………………………………………………………………………… (i) Statethefunctionofmanganese(IV)oxide
………………………………………………………………………………………………………………………………. (i i i) W rite equation forthe reaction.(1 1⁄2 m arks)
…………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………….
(b) Chlorinewasbubblesthroughasaturatedsolutionofpotassiumiodide.
(i)Statewhatisobserved.(1mark)
…………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………
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(i) Giveareasonforyourobservation.(1mark)
…………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………….
(c) Giveareasonwhychlorinebelongstogroup(VI)intheperiodictable.(1⁄2 marks)
…………………………………………………………………………………………………………………………………………
6. (a)oxygencanbepreparedbyusingsodiumperoxideandwater
(i)writeanequationforthereactionthattakesplacebetweensodiumperoxideandwater
1
(1 marks)
2
. .
(i i)nam e one othersubstance from w hich oxygen can be prepared in the laboratory(01mark)
. (b)(i)statetheconditionsunderwhichoxygencanreactwithiron(01mark)
. .
(i)writeanequationforthereactionifironistreatedwithoxygenunderthecondition(s)
1 youhavestatedin(b)(i)above(1 marks)
2
. .
7. AnitrateofmetalY whenheateddecomposedtoform ayelowresidueZ when hotwhichturnedwhiteoncooling.
(a) (i) Identifythenitrateandtheresidue. (01
mark)
.
(i) Writeanequationforthereactionthattookplace. (11⁄2 marks)
. 5

.
(b) (i) DeterminethemassofZif1.89gofthenitratewasdecomposed. (11⁄2marks)
. . . .
(i) statewhatwhatobservedwhentheresiduewasreactedwithdilute hydrochloricacid
(01mark)
.
.
8. (a) (i) Whatarealotropes? (01mark)
. .
(i) Namethecrystalinealotropesofcarbon. (01mark)
. .
(b) Giveanytwousesofeachofthealotropesnamedin(a)(i)above. (02marks)
. . . (c)Nameanyotheralotropeofcarbonotherthanthosenamedin(a)above
………………………………………………………………………………………………………………………………………
………………………………………
9. (a) AhydratedsaltTconsistsof20%iron,11%suphur,23%oxygenand45.3% waterofcrystalization.CalculatetheempiricalformulaofT (21⁄2marks)
6

. . . . . . .
(b) deducethemolecularformulaofofT(RMM ofT=278)(1mark)
. . . (c) Writeanionicequationforthereactionthattookplacebetweenasolution ofT and chlorine (11⁄2 m arks)
. .
10. (a) State;
(i) themaincomponentsofair. (01
mark)
.
(i) thecomponent(s)ofairthatafectsironfilings. (01mark)
.
(b) Describeanexperimentyoucaryouttoshowthatoneofthecomponents in(a)(i)af fectsironfilings(Nodiagram required). (31⁄2 marks)
. .
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. . . . . .
SECTIONB:(30MARKS) AnswerTWOquestionsfrom thissection
11(a)TheatomicnumbersoftheelementsP,QandRare14,17,and19respectively
(i)whatismeantbytheatomicnumber?(01mark)
(i)writetheelectronicstructuresofP,QandR(03marks)
(b)PandQcaneachcombinewithQtoform compounds
(i)usethevalencyelectronstoexplainbrieflyhow atomsofPandQ ,RandQ form compounds(06marks)
(i)writethestructuralformulaofthecompoundformedwhenRcombineswithQ (c)statetwopropertiesofthecompoundsformedbetween (i)PandQ(02marks)
(i)RandQ(02marks)
1 12(a)Describethestructureofgraphite(5 marks)
2
(b ) s ta te tw o p ro p e rtie s in w h ic h g ra p h ite d if fe rs fro m d ia m o n d (0 2 m a rk s )
(c)graphitewasheatedinexcessairandthegasgivenofpassedthroughcalcium hydroxideforalongtime.
(i)statewhatwasobserved(01mark) (i)writeequation(s)forthereactions(03marks) (d)carbonmoxidereactswithiron(i)accordingtothefolowingequation;
Fe2O3(s)+3CO(g) 2Fe(s)+3CO2(l) Ifexcesscarbonmonoxidewaspassedover3.5gofhotiron(i)oxide,calculatethe
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• 1 volumeofCarbondioxideevolvedats.t.p.(3 marks)
  2
  13(a)withthehelpoftheequations.Outlinehow adrysampleofammoniacanbe preparedinthelaboratorystartingammonium chloride(diagram notrequired)
  (b)drawawellabeleddiagram ofthesetupoftheapparatusisverysolubleinwater (03marks)
  (c)usinfequationswhetherpossible,explainwhywhendryammoniaispassedover
  1 heatedlead(i)oxide,acolourlessliquidandagreysolidisobtained(3 marks)
  2
  (d ) A m m o n iu m n itra te d is s o lv e s in w a te r a c c o rd in g to th e fo l lo w in g e q u a tio n ;
  NH4NO3(s)+H2O(l) NH4OH(aq)+HNO3(l)
  Explainusingequations,whyextensiveuseofammonium asafertilisercanmakethe
  1 soilacidic3 mark
  2
  END
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