cambridge international examinations cambridge ......3 s 2018 97012218 [turn over (d) tumbaga is an...

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Write your Centre number, candidate number and name on all the work you hand in.Write in dark blue or black pen.You may use an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.

Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.A Data Booklet is provided.

At the end of the examination, fasten all your work securely together.The number of marks is given in brackets [ ] at the end of each question or part question.

CHEMISTRY 9701/22Paper 2 AS Level Structured Questions October/November 2018

1 hour 15 minutes

Candidates answer on the Question Paper.

Additional Materials: Data Booklet

Cambridge International ExaminationsCambridge International Advanced Subsidiary and Advanced Level

This document consists of 13 printed pages and 3 blank pages.

[Turn overIB18 11_9701_22/6RP© UCLES 2018

*5824876239*

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Answer all the questions in the spaces provided.

1 ThemodelofthenuclearatomwasfirstproposedbyErnestRutherford.Hedevelopedthismodelonthebasisofresultsobtainedfromanexperimentusinggoldmetalfoil.

(a) Completethetablewithinformationfortwooftheparticlesinanatomof197Au.

particle relativemassrelativecharge

locationwithin atom

totalnumberinan atom of 197Au

electron 0.0005 –1 79

neutron nucleus

[4]

(b) Statethetypeofbondingingold.

.............................................................................................................................................. [1]

(c) Asampleofgoldfoundintheearthconsistsofonlyoneisotope.

(i) Explainwhatismeantbythetermisotopes.

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [2]

(ii) Adifferentsampleofgoldcontainsmorethanoneisotope.

Suggestwhythisdifferentsampleofgoldhasthesamechemical properties as the sample found in the earth.

.............................................................................................................................................

....................................................................................................................................... [1]

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(d) Tumbaga is an alloy of copper and gold.A sample of tumbaga was analysed. Themassspectrum of the sample is shown.

63 65

56.36

25.14

197m / e

percentageabundance

0

x

(i) Calculatethepercentageabundanceofgold,x,inthesampleoftumbaga.

x = .............................. % [1]

(ii) Calculatetherelativeatomicmass,Ar,ofthecopperpresentinthissample. Giveyouranswertotwo decimal places.

Ar (Cu) = .............................. [2]

[Total: 11]

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2 Thetablegivessomedataforelementsinthethirdperiodandsomeoftheircompounds.

element Na Mg Al Si P S

typeofbonding metallic covalent covalent

formulaofoxide P4O10 SO2

formula of chloride NaCl MgCl 2 SCl 2

(a) Completethetabletoshowthebondingintheelements,andtheformulaeoftheiroxidesandchlorides. [3]

(b) SCl 2isformedinthefollowingreaction.

S2Cl 2(l) + Cl 2(g) 2SCl 2(l) ΔH = – 40.6 kJ mol–1

(i) Completethe‘dot-and-cross’diagramtoshowthebondinginamoleculeofSCl 2. Show outerelectronsonly.

[1]

(ii) CompleteandfullylabelthereactionpathwaydiagramforthereactionbetweenS2Cl 2 and Cl 2.Includelabelsforactivationenergy,Ea,andenthalpychangeoftheforwardreaction,ΔH.

energy

progress of reaction

S2Cl 2(l) + Cl 2(g)

[2]

5


(c) (i) Ontheaxes,sketchthetrendinmeltingpointoftheelementsNatoS.

melting pointof element

Na Mg Al Si P S [1]

(ii) Givethreestatementstoexplainyoursketch.

1 ..........................................................................................................................................

.............................................................................................................................................

2 ..........................................................................................................................................

.............................................................................................................................................

3 ..........................................................................................................................................

............................................................................................................................................. [3]

(d) Write an equation for the reaction of P4O10 with water.

.............................................................................................................................................. [1]

(e) SO2canbereleasedintotheatmospherewhenfossilfuelscontainingsulfurareburnt.

StateandexplainoneenvironmentalconsequenceofthereleaseofSO2 into the atmosphere.

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

.............................................................................................................................................. [2]

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(f) Theelementsinthethirdperiodshowageneralincreaseintheirfirstionisationenergiesfromlefttoright.

Identify two pairs of successive elements in the third period that do not agree with thisstatement.

Foreachpair,explainwhythechangeinionisationenergydoesnotagreewiththisstatement.

Use of the Data Booklet may help you to answer this question.

pair 1 ..........................................................................................................................................

explanation ................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

pair 2 ..........................................................................................................................................

explanation ................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

.................................................................................................................................................... [4]

[Total: 17]

7


3 Trihalomethanes are organicmolecules inwhich three of the hydrogen atoms ofmethane arereplacedbyhalogenatoms,forexampleCHF3.

(a) TheequationshowsareactiontoproduceCHF3.

CHI3(s)+3AgF(s) CHF3(g)+3AgI(s)

Usethedatatocalculatetheenthalpychangeofreaction,ΔHr,forthisformationofCHF3.

compound enthalpychangeofformation,ΔHf / kJ mol–1

CHI3(s) –182.1

CHF3(g) – 692.9

AgF(s) –204.6

AgI(s) – 61.8

enthalpychangeofreaction,ΔHr = .............................. kJ mol–1 [3]

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(b) ThegraphshowstherelationshipbetweenpV and patagiventemperatureforCHF3 and an idealgas.

pV

0 200 400 600p / atm

800 1000

CHF3

ideal gas

(i) CHF3isnotanidealgas.

State threebasicassumptionsthatscientistsmakeaboutthepropertiesofidealgases.

1 ..........................................................................................................................................

2 ..........................................................................................................................................

3 .......................................................................................................................................... [3]

(ii) ExplainwhyCHF3deviatesfromthepropertiesofanidealgasatpressuresgreaterthan300 atm.

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [2]

9


(c) Adifferenttrihalomethane,CHCl 3,reactswithO2toproducecarbonyldichloride.HCl(g)isalsoreleased as a product of this reaction.

C

carbonyl dichloride

ClCl

O

(i) WriteanequationforthisreactionofCHCl 3 with O2.

....................................................................................................................................... [1]

(ii) TheconversionofCHCl 3tocarbonyldichloridecanbemonitoredbyinfra-redspectroscopy. Theinfra-redspectrumofcarbonyldichlorideisshown.

100

50

0

transmittance

4000 3000 2000wavenumber / cm–11500 1000 700

On the infra-red spectrumof carbonyl dichloride identifywithanX theabsorption thatwould notbepresentinaninfra-redspectrumofCHCl 3.

Explainyouranswer.

.............................................................................................................................................

............................................................................................................................................. [2]

(iii) Suggestanotherdifferencebetweentheinfra-redspectraofCHCl 3andcarbonyldichloride.

.............................................................................................................................................

....................................................................................................................................... [1]

[Total: 12]

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4 Thediagramshowsareactionsequencestartingfromethanal.

C P

ethanal

H3CH3C

CO2H

CO2H

OH

C CC

RQ

H

HH

O

C

S

H3C

O

H

CO2HHCN and NaCN

reaction 1H2SO4(aq)reaction 2 reaction 3

reaction 4

H

(a) (i) Draw the displayed formula of P.

[1]

(ii) Namethetypeofchemicalreactionthatoccursinreaction3.

....................................................................................................................................... [1]

(iii) Write an equation to represent reaction 4.

Use[O]torepresenttheoxidisingagent.

....................................................................................................................................... [1]

(iv) Statethereagentsandconditionsforreaction4.

....................................................................................................................................... [1]

11


(b) Compound Qisformedasamixtureoftwoopticalisomers.

(i) Explainwhatismeantbythetermoptical isomers.

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [1]

(ii) Draw the two optical isomers of Q,showingclearlytheirthree-dimensionalstructures.

[2]

(c) Rcanbeusedtomakeapolymer,W,intwosteps.

R Waddition

polymerisationintermediatepolymer

NaOH(aq)

Draw one repeat unit of W.

[3]

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(d) Compound Z,H2C=CHCH3,isproducedfromR.

Zcanbeusedinatwo-stepprocesstoproduce2-aminopropane.

(i) In the first step,Z reactswithHBr to form two products.The structure of the productdependsonwhichintermediateisformed,intermediateI or intermediate II.

intermediate I

CH3C

H3C

H

+

intermediate II

CH3C

H

H H

H

C+

ExplainwhyintermediateIismorelikelytoformthanintermediateII.

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [2]

(ii) When intermediate Iforms,theproductofthefirststepisT.

CompletethediagramtoshowthemechanismfortheconversionofZ to T. Includeallrelevantcharges,partialcharges,curlyarrowsandlonepairs.

CCH

HH

Br

H

CH3 CH3C

H3C

H

+ H3C

Br

H

C

TZ

CH3

[3]

(iii) Tcanthenbeconvertedto2-aminopropane.

NH3ethanol

H3C

Br

H

C

T

CH3 H3C

NH2

H

C

2-aminopropane

CH3

Name the mechanism for this conversion.

....................................................................................................................................... [1]

13


(e) (i) Compound S,CH3COCO2H,canbereducedbyLiAlH4.

Completetheequationusingstructuralformulaetorepresentthisreaction. Use[H]torepresentthereducingagent.

CH3COCO2H+ ............................................................................................................ [2]

OtherreducingagentscontainingGroup1metalcationsincludeLiBH4,NaBH4andKBH4. Thestrengthofthereducingagentdependsonthesizeofitscation.

(ii) GivetheelectronicconfigurationoftheNa+ cation.

1s2 ................................................................................................................................. [1]

(iii) SuggestwhyionicradiusincreasesdownGroup1.

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [1]

[Total: 20]

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cambridge international examinations cambridge ......3 s 2018 97012218 [turn over (d) tumbaga is an...

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