8/6/2019 F334 JAN 10 - MS (New Spec)

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F334

Mar

kScheme

January2010

F334

ChemistryofM

aterials

Question

E

xpectedAnswers

Marks

AdditionalGuidance

1

(a

)

2-hydroxypropanoicac

id

2

markindep

endently

2-hydroxy

DONOTA

LLOW

hydroxyl

propanoicacid

ALLOWifpropan-and-oicareseparated

.

(b

)

(i)

(enantiomersare)isom

erswhosestructuresaremirror

imagesofoneanother

andarenon-superimposable

2

markindep

endently

mirrorimag

es

non-superimposable

IGNOREreferencesto4differentgroups

aroundaC

atom,optic

alisomerism,variouschiralwo

rds&rotationof

planepolarisedlight

(ii)

OH

HOOC H

3C

H

OH

COOH

CH3

H

2

3Dstructurecorrectforoneisomer

DONOTA

LLOW9

0or180degreeangle

sbetweenthe

twobonds

intheplaneofthepaper

mirror-imagecorrect(musthave4bonds

aroundtheC)

ALLOWec

ffornon3Dstructurewithfourdifferent

groupsonly

IGNOREth

ewaythegroupsarebondedtocarboneg

-OHorHO,sameforCOOH&CH3

(c)

(i)

P=C

Q=A

R=B

1

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8/6/2019 F334 JAN 10 - MS (New Spec)

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F334

MarkScheme

January2010

Question

E

xpectedAnswers

Marks

AdditionalGuidance

(ii)

P=(C)doesnotfizz/

doesnotreact/withNa2CO3A

NDso

noCOOHgrouppres

ent/AW

Q=nophenolgroup(inA),soFeCl3remainsyellow/AW

R=(Bhas)bothphen

ol&carboxylicacid(COOH)(sowill

turnFeCl3purpleandwillfizzwithNa2CO3)/AW

Thewordsinbracketsareonlyneedediftestsno

t

discussedforP&Q.

3

ifanswers

to(i)areincorrect/noresponse

award1mark

forcorrect

answersforhavingbothtests

forphenoland

carboxylicacid:

ie:purplesolu

tion=phenol

ANDacids

fizzwithcarbonate

IGNOREP

isCasitturnsFeCl3purple

IGNOREQ

isAasitfizzes&istherefore

acarboxylicacid

(d)

C

because:

(broad)peakataround

3250(cm1)indicatesalcohol

or

phenol/OH/hydroxylgroup

nopeakat17001725

(cm1)sonoC=O(inCOOH)

present

3

IGNOREa

nyreferencetocarboxylicacid

forthe3250

peak

ALLOWa

rangearound3250

Peaksmay

beidentifiedonthediagram

IGNOREa

llotherpeaks

(e)

(i)

nucleophilicaddition

2

nucleophilic

addition

markindep

endently

22

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F334

MarkScheme

January2010

Question

E

xpectedAnswers

Marks

AdditionalGuidance

(ii)

O

O

CN

CN

4

curlyarrowshowingattackbyCNatC=

Ocarbon

DONOTA

LLOW

arrowstartingfromNofCN/single-

headedarr

owsbutgive1markifbothare

singleheaded

butotherwisecorrect

C=Obond

polarisedcorrectly

curlyarrow

showingmovementofdouble

bond

finalstructurecorrectALLOWanycorrectstructural

formulanotjustskeletal

OMUSTbeve

IGNOREa

nyfurtherreactionshowingOgainingH+

(iii)

theratedeterminingstep(slowstep)doesnotinvolve

water

(since)waterdoesnot

appearintherateequation/w

ateris

zeroorder

Sincewater/H+requiredtoformproductitmustreactina

subsequent(fast)step

/theremustbeatleast2steps

inthe

reaction/AW

OR

theratedeterminingstep(slowstep)onlyinvolvesethanal&

cyanide

(becauseonly)ethana

l&cyanideappearintherate

equation

andsowatermustrea

ctinasubsequentstep

3

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8/6/2019 F334 JAN 10 - MS (New Spec)

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F334

MarkScheme

January2010

Question

E

xpectedAnswers

Marks

AdditionalGuidance

2

(a

)

Fe

3+willoxidiseCu/O

RA

ORCuloseselectronstof

ormCu

2+/ORA

becauseelectrodepo

tentialofFe3+/

(Fe2+)ismore

positive/ORA(involv

estheCopperhalf-cell)

ORUsesEcellcalculationtoshow

reactionisfeasible

Cu+2Fe

3+

Cu

2++

2Fe

2+

3

ALLOWFe(III)andCu(II)

DONOTA

LLOW

electronegativityorhigher/loweror

larger/smaller

IGNOREstatesymbols

(b

)

(i)

PtelectrodeforFe

3+/

Fe

2+halfcell

inFe3+/

Fe2+

CuelectrodeinCu

2+

saltbridgelabelledandinsolutions

conditions:1moldm3

and298K/25C

5

ALLOWCuSO4etc.insteadofCu

2+

ALLOW1

molar/1M

(ii)

0.43V

1

IGNOREa

nysign

(c)

(i)

Copper(I)iodide

1

DONOTA

LLOWcopperiodide

ALLOWC

opperIiodide

25

8/6/2019 F334 JAN 10 - MS (New Spec)

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F334

MarkScheme

January2010

Question

E

xpectedAnswers

Marks

AdditionalGuidance

(ii)

1.molesofthiosulfate

=0.200x(20.5/1000)=0.0041

2.(molesofiodine(I2)

=0.5xanswerfrom1(0.0041

)and

molesofCu

2+(aq)in25.0cm

3=

2x0.5xanswer

from1(0.0041))=0.0041

3.molesofCu

2+(aq)in

250cm3=

10xanswer

from1(0.0041)=0.04

10

4.massofCuincoin=

answerfrom3(0.0410)

x63.5=2.6035g

5.%ofCuincoin=(answerfrom4(2.6035)/3.47)

x100=75.0

6.(3sig.figs.)

6

75.0withn

o/incompleteworkingscores6marks.

Themarks

areawardedfortheworkingoutgivenin

bold:

Iffinalanswerisincorrectpleaseannotatemarksgiven

withticksA

NDcrosseswhereerrorshave

occurredeg

missingou

tstep3.

1.molesofthiosulfate=0.0041moles

2.correctm

olesofCu

2+(aq)in25.0cm

3e

cffrom1

3.molesofCu

2+(aq)in250cm3=

10xm

olesof

thiosulfa

te

4.massof

Cuincoin=molesofCu

2+(aq)

in250cm3

x63.5

5.%ofCu

incoin=massofCuincoinx100

6.correct/incorrectanswerMUSTbegive

nto3sig

figs.

Steps3&

4maybeinadifferentorder

(d)

(i)

(transmits)Blue

Cu

2+(aq)absorbred/

orangelight

QWCabsorb(s)/absorbing/absorption/absorban

ce/

absorbed

Oneofthesewordsha

stobeusedtogainthesecondmark

andspellingmustbec

orrect

2

IGNOREp

ale,deeporlightetc.referring

toblue,reflects

DONOTA

LLOW

green

ALLOWco

mplementarycolour/specificfrequencies/

wavelength

soflightareabsorbed

DONOTA

LLOW

allotherfrequencies/c

olour/AW

Useofem

itisaCONforthe2ndmark

26

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F334

MarkScheme

January2010

Question

E

xpectedAnswers

Marks

AdditionalGuidance

(ii)

Ligandsubstitution

[CuCl4]2

2

ALLOWlig

andreplacement/displacement/exchangeor

complexfo

rmation

Thecharge

isrequired

ALLOW[C

u(H2O)2Cl4]2

(iii)

Anyfivefroma-f:

a.makeupstandards

olutions/ofknownconcentrations(of

Cu

2+(aq))

b.chooseasuitablefilter/setthecolorimetertoasuitable

wavelength

c.zerocolorimeterwithwater/solvent/AW

d.measureabsorbance/absorptionofstandardso

lutions/

AW

e.plotcalibrationcurve

f.measureunknown

AND

g.QWC

readoffconc

entrationfromcalibrationcurve

/AW

6

IGNOREtr

ansmittance

Total

26

27

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F334

MarkScheme

January2010

Questio

n

Ex

pectedAnswers

Marks

AdditionalGuidance

(a)

(i)

O

O

H

O

P

HO

O O

OH

2

thelinkbetweenphosphategroupandan

yOHgroupon

thesugar

ieP-O-CH2-C(inringnexttoO-)

orP-O-C(inring)dependingwhich-OHg

roupisused

correctlink

age(P-O-CH2-C)andrestofstructurecorrect

3

(ii)

Water/H2Oandconden

sation(reaction)

1

(iii)

N

NN

O

H

H

H

1

ALLOW

ALLOWif

theN-Hgroupiscircled

(iv)

lonepair(ofelectrons)onN/amine(group)

acceptsaproton/H+

2

N

O

HN

H

H

28

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F334

MarkScheme

January2010

Questio

n

Ex

pectedAnswers

Marks

AdditionalGuidance

(b)

N

N

N N

N

H

H

3

2hydrogen

bondscorrect

DONOTA

LLOW

morethan2bonds

correctpolarities(all3)ononegroupofa

toms

lonepairontheNORO

(c)

twostrands(notthree)

phosphategroupsonthe

outside(notontheinside)

basesfaceintothecentr

e(nottheoutside)

3

ALLOWdo

ublehelix

IGNOREp

hosphatebackbone

(d)

forremoval:

infringementofpersonal

liberty/AW/

'fingerprint'notuniqueon

lyprobability/

techniquesusednotfoolproof/

law/typeofgovernmentmightchangechangingacces

sibility/

AW

againstremoval:

helpstosolvemanycrim

es,particularly'cold'crimes/

'innocentuntilprovedguilty'/AW

futureresearchintodisease

2

IGNOREh

ackingintodatabase/leakage

ofdata

(NOTE:probabilitymayonlybe1in20forsome

population

groups)

29

Total

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F334

MarkScheme

January2010

Question

ExpectedAnswers

Marks

AdditionalGuidance

(a)

Cl

HN

O

2

1markfor

eachstructurecorrect

DONOTA

LLOWm

issingHatomsifstructuralformulae

aredrawn

4

(b)

(i)

thereare(two)differentgroupsoneachcarbonofaC

=Cin

neoprene

thesegroupscannotrotateaboutthedoublebond

2

Maybeshowninadiagram

ALLOWre

stricted/limitedrotationabout

thedoublebond

(ii)

(lesstranslinkages)w

illmakethechainslesslinear/less

regular/lessordered/

ORA

sotheycannotlineup

/bearrangedsoregularly/clo

sely

andthecrystallinitywillbereduced

2

ALLOWch

ainshaveakink/aremorerandomlyarranged

Note:

1st markis

forshapeofchain,

2ndmarkis

forrelativearrangementofchains.

(c)

CONHgroup/NHgro

up/amidegroupallowsnylon

toform

hydrogenbondswithw

atermolecules

nohydrogenbondinginneoprene

watermoleculeswillforcechainsfurtherapart/chainswillnot

fitascloselytogether/

AW

chainslesscrystalline/weakerintermolecularforcessoTgwill

belowered

4

IGNOREc

hainsslidingovereachother

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F334

MarkScheme

January2010

Question

ExpectedAnswers

Marks

AdditionalGuidance

(d)

H2N

O

O

Na

2

6carbonatomsandNH2group

COO

ALLOWsk

eletaloranyequivalent/altern

ativestructural

formula

DONOTA

LLOWs

tructureswithmissing

Hatoms

Total

12

31

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F334

MarkScheme

January2010

Question

E

xpectedAnswers

Marks

AdditionalGuidance

(a)

(i)

3H2S+2MnO4

+

2H+

2MnO2

+3S+4H2O

1

all4numbersMUSTbecorrect

5

(ii)

oxidationstate=+4

1

DONOTA

LLOW

4+OR4

(b)

(i)

iron(III)hydroxide

1

DONOTA

LLOWironhydroxide/Fe(OH)3

(ii)

Fe

3+(aq)+3OH(aq)

Fe(OH)3(s)

2

equationcorrect

statesymb

olscorrect

ALLOWec

fforiron(II)hydroxidein(i)

(c)

(i)

Thelargeexcessofethanedioateandacidmeansthattheir

concentrationswerevirtuallyconstantduringthereac

tion/

concentrationshardlychanged/concentrationswere

highso

littleeffectonrate/AW

1

Alargeex

cessofethanedioateandacid

byitselfdoes

notgetthe

mark

IGNOREe

xcessethanedioateandacidn

otlimittherate

ofreaction/AW

Lookforco

ncentrationinanswer

(ii)

Oneofthefollowing:

Method1half-lives

determinationofatlea

sttwohalf-lives,13-15s

half-lifeconstant

firstorder

OR

Method2findingrateatdifferentconcentrations

calculationofatleastt

worates

rateisproportionaltoconcentration

firstorder

3

Twovaluesforhalf-lifeMUSTbegiven

Workingm

ustbeshownaseitheracalculationorbylines

ongraph.

32

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F334

MarkScheme

January2010

33

E

xpectedAnswers

Marks

AdditionalGuidance

Question

(iii)

3d

4s

1

(d

)

Onefromthefollowing

:

lossofCO2/CO2

prod

ucedbyweighing/gascollection/

measuringmilkinesso

flime-water

OR

titrationofMnO4

wi

th(standard)Fe

2+(aq)

OR

titrationofH+(aq)decreasew

ithOH/

CO3

2(aq)

OR

measurepHchangeH

+ionsusedinthereaction

2

Thetwopa

rtsaremarkedindependently

ALLOWga

sforCO2andmeasuringvolum

eforgas

collection

Total

12