CHEMISTRY – CH2pmt.physicsandmathstutor.com/download/Chemistry/A-level/Past-Pap… · CFCs are...

1092

0100

01

ADDITIONAL MATERIALS

In addition to this examination paper, you will need a:• calculator;• Data SheetcontainingaPeriodic Table supplied by WJEC. Refer to it for any relative atomic masses you require.

INSTRUCTIONS TO CANDIDATES

Useblackinkorblackball-pointpen.Donotusegelpenorcorrectionfluid.Writeyourname,centrenumberandcandidatenumberinthespacesatthetopofthispage.Section A Answer allquestionsinthespacesprovided.Section B Answer allquestionsinthespacesprovided.CandidatesareadvisedtoallocatetheirtimeappropriatelybetweenSection A (10 marks) andSection B (70 marks).

INFORMATION FOR CANDIDATES

Thenumberofmarksisgiveninbracketsattheendofeachquestionorpart-question.Themaximummarkforthispaperis80.Youranswersmustberelevantandmustmakefulluseoftheinformationgiventobeawardedfullmarksforaquestion.The QWC labelalongsideparticularpart-questionsindicatesthosewheretheQualityofWrittenCommunicationisassessed.If you runout of space, use the additional page(s) at the backof the booklet, taking care tonumberthequestion(s)correctly.

SM*(W13-1092-01)

Surname

Other Names

CandidateNumber

2

CentreNumber

© WJEC CBAC Ltd.

GCE AS/A level

1092/01

CHEMISTRY – CH2

A.M. WEDNESDAY, 16 January 2013

1½ hours

FOR EXAMINER’SUSE ONLY

Section Question Mark

A 1-7

B 8

9

10

11

12

TOTAL MARK

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SECTION A

Answer all questions in the spaces provided.

1. Calciumandmagnesiumareessentialelementsinlivingthings.Giveoneuseofeachelementinbiologicalsystems. [1]

Magnesium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Calcium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. Givethesystematicnameofthemoleculeshownbelow. [1]

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OH

3. Theelectronegativityvaluesofthehalogensarelistedbelow.

Atom F Cl Br I At

Electronegativityvalue 4.0 3.0 2.9 2.6 2.2

(a) Define the term electronegativity. [1]

(b) Usethedatainthetabletoidentifyanydipolespresentinthefollowingbonds,markingtheirpolarityclearly. [1]

F Cl At ClF Cl At Cl

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3Examiner

only4. Cyclohexaneisanexampleofahydrocarboncontainingaringofcarbonatoms.Itsstructure

is shown below.

© WJEC CBAC Ltd.

C

C

CCH

CCH

HH

HH

HH

HH

HH

Givetheempirical formulaofthiscompound. [1]

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

5. (a) Writethelettercorrespondingtothecorrectelectronicstructureofanatomthatisamember of the d-blockintheboxbelow. [1]

A 1s22s22p63s23p63d104s24p1

B 1s22s22p63s23p63d6

C 1s22s22p63s23p63d64s2

D 1s22s22p63s23p64s2

(b) Writethelettercorrespondingtotheelectronicstructureoftheatomwiththehighestfirstionisationenergyintheboxbelow. [1]

A 1s22s22p63s23p6

B 1s22s22p6

C 1s22s22p63s2

D 1s22s22p63s23p4

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6. Thegasoxygen,O2,isconvertedintoozone,O3, in the upper atmosphere. The equation for thisprocessis:

3O2 2O3

Useoxidationstatestoexplainwhythisisnotaredoxreaction. [2]

7. Recentadvancesinchemistryhaveproducedarangeofsmartmaterials.

Givethemeaningofthetermsmart material. [1]

Total Section A [10]

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SECTION B

Answer all questions in the spaces provided.

8. Bariumchlorideisahighlytoxiccompoundthatisfrequentlyusedinthelaboratory.

(a) Aqueousbariumchloridecanbeusedtotestforsulfateionsinsolution.

(i) Writeanionicequationforthereactionthatoccurswhenaqueousbariumchlorideisaddedtoasolutioncontainingsulfateions. [1]

(ii) Givetheobservationexpectedforapositiveresultinthischemicaltest. [1]

(b) Asolutionofbariumchloridecanbeidentifiedusingseparatetestsforbariumionsandchlorideions.

(i) Aflametestcanbeusedtoprovethatthesolutioncontainsbariumions.Statetheflamecolourthatwouldbeseen. [1]

(ii) Giveachemicaltesttoshowthatthesolutioncontainschlorideions.Youranswershouldincludethereagent(s)andexpectedobservation(s). [2]

Reagent(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Observation(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c) The solubility of barium chloride at twodifferent temperatures is given in the tablebelow.

© WJEC CBAC Ltd.

Temperature / °C Solubility of BaCl2/gdm–3

0 312

20 358

Calculatethemassofsolidbariumchloridethatwouldbeobtainedbycooling200cm3 ofasaturatedsolutionofbariumchloridefrom20°Cto0°C. [2]

Mass = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . g

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(d) When solid barium chloride is crystallised from solution, it produces the hydrate BaCl2 . xH2O.The relativemolecularmass (Mr )of thishydratewas found tobe244.Calculatethevalueofx in this formula. [2]

x = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(e) Jackwishestoprepareasolutionofbariumchloridestartingwiththeinsolublesolidbariumcarbonateanddilutehydrochloricacid.

(i) Writetheequationforthisreaction. [1]

(ii) Jackmeasured50.0cm3ofhydrochloricacidofconcentration0.500moldm–3. I Calculatethenumberofmolesofhydrochloricacidinthissolution. [2]

Moles of hydrochloric acid = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mol

II Headdedan excessof solidbariumcarbonate to thedilutehydrochloricacid. Suggest how a pure solution of barium chloride could be obtainedfromthereactionmixture. [1]

III Calculatethemaximummassofhydratedbariumchloride(Mr=244)thatcouldbeproducedinthisreaction. [2]

Maximum mass of hydrated barium chloride = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . g

Total [15]

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9. Chloromethanecanbeproducedbythechlorinationofmethanegas.

(a) Duringtheinitiationstageofthisprocess,chlorinefreeradicalsareproduced.

(i) Givethecondition(s)requiredforthisinitiationstage. [1]

(ii) Statewhatismeantbyafree radical. [1]

(b) Write the equation(s) for thepropagation stage(s) toproduce chloromethane startingwithmethaneandchlorinefreeradicals. [2]

(c) Apartfromchloromethane,arangeofothercompoundsareproducedinsmallamountsduringthereaction.

(i) Oneofthecompoundsproducedinthereactionisethane.Showhowthiscompoundisproduced. [1]

(ii) Anotherofthecompoundsproducedcontains24.3%carbon,4.1%hydrogenand71.6%chlorinebymass.Calculatetheempirical formulaofthiscompound. [2]

Empirical formula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

© WJEC CBAC Ltd.

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9Examiner

only (d) Chloromethanecanbeconvertedintomethanolbyreactionwithhydroxideions.

(i) Classifythemechanismofthisreaction. [1]

(ii) Theboilingtemperaturesofchloromethaneandmethanolaregiveninthetablebelow.

© WJEC CBAC Ltd.

Compound Boilingtemperature/K

chloromethane,CH3Cl 249

methanol, CH3OH 338

Explain why the boiling temperature of methanol is higher than the boilingtemperatureofchloromethane. [3]

(iii) Methanol can then be converted to methanoic acid. Give the reagent(s) andcondition(s)requiredforthisreaction. [2]

Reagent(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Condition(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

9201

0009

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(e) CFCs are another class of organic compounds. They contain chlorine, fluorine andcarbon.Thesecompoundsoncehadarangeofuses,howevertheiruseisnowavoidedduetotheireffectontheozonelayerwhichispartoftheupper atmosphere.

The table shows the lifetime of some compounds in the lower atmosphere and their relativeozonedepletionpotential(RODP),takingCCl3Fashavingavalueof1.0.TheRODPismeasuredbymixingacompoundwithozoneinalaboratoryexperiment.

© WJEC CBAC Ltd.

Compound Formula Lifetime in the loweratmosphere

Relativeozonedepletionpotential(RODP)

A CHF3 243years 0.01

B CCl2F2 20 years 0.86

C CCl3F 75years 1.00

D CBrClF2 120 days 10.00

By referring to this table, explain why CFCs B and C are far more harmful than compoundsA and D.

YouranswershouldexplainhowandwhyCFCsaffecttheozonelayer. [3]

Total [16]

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10. Aluminium,boronandnitrogenallformchloridescontainingthreechlorineatoms,XCl3.

(a) Molecules of boron chloride, BCl3, and molecules of nitrogen chloride, NCl3, havedifferent shapes.

UseVSEPR(valenceshellelectronpairrepulsion)theorytostateandexplaintheshapesofthesemolecules. [6]

QWC [2]

© WJEC CBAC Ltd.

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13Examiner

only (b) The boron atom in boron chloride, BCl3, is described as being electron deficient.

DrawadotandcrossdiagramforBCl3 and use it to show what is meant by the term electron deficient. [2]

(c) Nitrogenchloride,NCl3,isinsolubleincoldwaterwhilstthesimilarcompoundammonia,NH3,isverysoluble.Explainthisdifferenceinbehaviour. [2]

(d) Aluminium chloride, AlCl3, forms a dimer that contains both covalent bonds andcoordinatebonds.Describewhat ismeantby the termscovalent bond and coordinate bond. [2]

Total [14]

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only11. (a) Bothsodiumchlorideandcaesiumchloridehavegiantionicstructures.

(i) Drawalabelleddiagramtoshowthearrangementofionsinacrystalofcaesiumchloride. [2]

(ii) Giveareasonwhysodiumchloridehasadifferentstructurefromcaesiumchloride. [1]

© WJEC CBAC Ltd.

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15Examiner

only (b) Bothdiamondandgraphitehavegiantcovalentstructures.

(i) Describethestructureandbondingingraphite. [3] QWC [1]

(ii) Explainwhygraphitecanconductelectricitywhilstdiamondcannot. [2]

(iii) Iodine,I2,alsocontainscovalentbonds.Explainwhysolidiodinecanbeconvertedintoavapouratamuchlowertemperaturethandiamond. [3]

Total [12]

© WJEC CBAC Ltd.

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12. But-2-eneisausefulstartingmaterialfortheproductionofsyntheticrubber.

(a) But-2-enecanbeproducedfromcrudeoilbyfractionaldistillationandthencracking.

(i) Explainwhyfractionaldistillationcanbeusedtoseparatemoleculeswithdifferentnumbersofcarbonatoms. [1]

(ii) Writetheequationforacrackingreactionthatproducesbut-2-enefromdecane,C10H22. [1]

(b) Brominesolutioncanbeusedtodistinguishbetweenbut-2-eneandbutane.

(i) Givethecolourchangethatwouldbeexpectedwhenbrominesolutionisaddedtobut-2-ene. [1]

(ii) Inasimilarreactionhydrogenbromidereactswithpropene.

Drawthemechanismofthereactionofpropenewithhydrogenbromideindicatingclearlyallchargesandthemovementofelectrons. [3]

© WJEC CBAC Ltd.

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17Examiner

only (iii) Propenecanbeproducedfromtheproductinpart(ii)byusingsodiumhydroxide. Givethecondition(s)requiredforthisreaction. [1]

(c) But-2-enecanexistasE-andZ-isomers. (i) Explainwhy but-2-ene can formE- andZ-isomerswhilst propene and butane

cannot. [2]

(ii) Drawtheskeletal formula for Z-but-2-ene. [1]

(d) Inindustry,butan-2-olcanbeproducedfrombut-2-ene.Thisusesthesamereagent(s)andcondition(s)astheproductionofethanolfromethene.

(i) Givethereagent(s)andcondition(s)usedforthisreaction. [2]

Reagent(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Condition(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(ii) Explainhowinfraredspectroscopycanbeusedtodistinguishbetweenbutan-2-olandbut-2-ene. [1]

Total[13]

Total Section B [70]

END OF PAPER

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© WJEC CBAC Ltd.

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SM*(W13-1092-01A)

GCE AS/A level

1092/01-A

CHEMISTRY – DATA SHEETFOR USE WITH CH2

A.M. WEDNESDAY, 16 January 2013

© WJEC CBAC Ltd.

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2

© WJEC CBAC Ltd.

Infrared Spectroscopy characteristic absorption values

Bond Wavenumber / cm–1

500 to 600650 to 800

1000 to 13001620 to 16701650 to 17502100 to 22502800 to 31002500 to 35503300 to 3500

C—BrC—ClC—OC CC OC NC—HO—HN—H

——

———

——

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© WJEC CBAC Ltd.

TH

E P

ER

IOD

IC T

AB

LE

12

Gro

up3

45

67

0

1 2 3 4 5 6 7

6.94 Li

Lith

ium

3

9.01 Be

Bery

llium

4

10.8 B

Bor

on 5

12.0 C

Car

bon

6

14.0 N

Nitr

ogen

7

16.0 O

Oxy

gen

8

19.0 F

Fluo

rine

9

20.2

Ne

Neo

n10

23.0

Na

Sodi

um11

24.3

Mg

Magn

esium

12

27.0 Al

Alum

inium

13

28.1 Si

Silic

on14

31.0 P

Phosp

horus

15

32.1 S

Sulfu

r16

35.5 Cl

Chlo

rine

17

40.0

Ar

Arg

on18

39.1 K

Pota

ssium

19

40.1

Ca

Cal

cium

20

45.0 Sc

Scan

dium

21

47.9 Ti

Tita

nium

22

50.9 V

Vana

dium

23

52.0 Cr

Chro

mium

24

54.9

Mn

Man

gane

se25

55.8 Fe Iron 26

58.9

Co

Cob

alt

27

58.7 Ni

Nic

kel

28

63.5

Cu

Cop

per

29

65.4

Zn

Zin

c30

69.7

Ga

Gal

lium

31

72.6

Ge

Germ

anium

32

74.9 As

Ars

enic

33

79.0 Se

Selen

ium

34

79.9 Br

Brom

ine

35

83.8

Kr

Kry

pton

36

85.5

Rb

Rubid

ium37

87.6 Sr

Stro

ntium

38

88.9 Y

Ytt

rium

39

91.2 Zr

Zirco

nium

40

92.9

Nb

Nio

bium

41

95.9

Mo

Molyb

denum

42

98.9 Tc

Tech

netiu

m43

101

Ru

Ruthe

nium

44

103

Rh

Rhod

ium

45

106

PdPa

lladiu

m46

108

Ag

Silv

er47

112

Cd

Cadm

ium48

115 In

Indi

um49

119

Sn Tin 50

122

SbAn

timon

y51

128

TeTe

lluriu

m52

127 I

Iodi

ne53

131

Xe

Xen

on54

133

Cs

Caes

ium

55

137

Ba

Bar

ium

56

139

La

Lanth

anum

57

179

Hf

Haf

nium

72

181

TaTa

ntalu

m73

184 W

Tung

sten

74

186

Re

Rhen

ium

75

190

Os

Osm

ium

76

192 Ir

Irid

ium

77

195 Pt

Plat

inum

78

197

Au

Gol

d79

201

Hg

Mer

cury

80

204

Tl

Thal

lium

81

207

Pb Lea

d82

209 Bi

Bism

uth

83

(210

)Po

Polo

nium

84

(210

)A

tA

stat

ine

85

(222

)R

nR

adon

86

(223

)Fr

Fran

cium

87

(226

)R

aR

adiu

m88

(227

)A

cAc

tiniu

m89

‣ ‣‣

1.01 H

Hydr

ogen

1

4.00 He

Heliu

m2

d Bl

ock

s Blo

ckPe

riod

p Bl

ock

140

Ce

Cer

ium

58

141 Pr

Pras

eody

mium

59

144

Nd

Neo

dym

ium

60

(147

)Pm

Prom

ethi

um61

150

SmSa

mar

ium

62

(153

)Eu

Euro

pium

63

157

Gd

Gad

oliniu

m64

159

Tb

Terb

ium

65

163

Dy

Dys

pros

ium66

165

Ho

Hol

miu

m67

167

ErEr

bium

68

169

TmTh

uliu

m69

173

Yb

Ytter

bium

70

175

LuLu

tetiu

m71

232

Th

Thor

ium

90

(231

)Pa

Prot

actin

ium91

238 U

Ura

nium

92

(237

)N

pN

eptu

nium

93

(242

)Pu

Plut

oniu

m94

(243

)A

mA

mer

icium

95

(247

)C

mC

uriu

m96

(245

)Bk

Berk

elium

97

(251

)C

fCa

liforn

ium98

(254

)E

sEi

nstei

nium

99

(253

)Fm

Ferm

ium

100

(256

)M

dM

ende

leviu

m10

1

(254

)N

oN

obeli

um10

2

(257

)Lr

Lawr

enciu

m10

3

f Blo

ck

‣ Lan

than

oid

e

lem

ents

‣‣ A

ctin

oid

e

lem

ents

Ar

Sym

bol

Name Z

rela

tive

atom

icm

ass

atom

icnu

mbe

r

PMT

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