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Mark Scheme (Results)Summer 2010

IGCSE

IGCSE Chemistry (4335) Paper 1F

Edexcel Limited. Registered in England and Wales No. 4496750Registered Office: One90 High Holborn, London WC1V 7BH

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Summer 2010

Publications Code UG024203

All the material in this publication is copyright

Edexcel Ltd 2010

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IGCSE CHEMISTRY 4335/1F SUMMER 2010

SECTION A

Question Mark Acceptable answers

1 a i M1 neutron

M2 proton

M3 electron

ii M1 nucleus

iii M1 12

iv M1 5

v M1 2.3 Accept any pun

b i M1 helium / beryllium / magnesium / calcium / strontium /barium / radium / He / Be / Mg / Ca / Sr / Ba / Ra

ii M1 hydrogen / helium / H / He Accept H2c it has isotopes / atoms have different numbers of neutrons / itis an average

Reject differelectrons

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2 a i M1 air / atmospheree any referenc

ii M1 natural gas / North Sea gas / hydrocarbons / named fraction /water / steam

Ignore methan

b i M3 iron / Fe Ignore referenII and III

ii M1 350 - 500

M2 100 - 350

iii M1 cross in box 3

M2 cross in box 4

M3 cross in box 5

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3 a M1 phosphorus

M2 potassium

Accept answerIgnore symbols

b i M1 cross in box 1ii M1 cross in same box as in bi Consequential

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4 a M1 denser than air / greater molar mass than air or nitrogen oroxygen Accept heavie

b M1 limewater / aqueous calcium hydroxide / Ca(OH)2(aq) Accept (aq) / equivalent to a

M2 milky / cloudy /chalky / white precipitate / white solid Ignore bubbles

c M1 copper(II) carbonate copper(II) oxide + carbon dioxide Both (II) needeReject any othIgnore heat

d M1 green

M2 black

Ignore qualifieReject all othe

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5 a M1 cross in box 1

M2 cross in box 4

b M1 filter or filtration / centrifuge and decant Accept descripReject any wro

c M1 wash (with water) / add water and filter Accept descrip

M2 dry / heat / warm / evaporate / leave in warm place / spreadonto filter paper / place in (warm) oven

Accept descripIgnore wrong csodium nitrate

If M1 and M2 inReject any wro

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6 a M1 covalent

b M1 low

M2 weak If high given foM3 molecules

Mark b indepgiven for M1, t

c M1 shared pairs of electrons between O and both H atoms Electrons can bany combinatio

M2 two electrons in O inner shellAND four more electrons in O outer shellAND no extra electrons in H

Accept these e

M2 dependent

d i M1 blue Ignore qualifie

Reject all otheM2 white / grey / pale(r) blue Accept all com

Reject all othe

ii M1 anhydrous copper(II) sulphate (II) not needed

iii M1 becomes blue / heat produced / temperature rises / formshydrated copper(II) sulphate / goes back to original colour

If different cocolour here

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7 a i M1 propene / propylene Accept prop-1-

ii M1 yellow / orange / brown Accept any com

Reject redM2 (goes) colourless / decolourised Ignore clear

Ignore discolou

Do not awardclear whether

b i M1 (contains) hydrogen and carbon / H and C (atoms) Reject molecu

M2 only Accept other wsuch as purely Award M2 onlyin M1

ii M1 only single bonds / no double bonds / no multiple bonds

iii M1 double bond between two carbon atomsM2 each carbon bonded to two hydrogen atoms M2 dependent

c M1 cross in box 1

M2 cross in box 5

d M1 C2H4 / CH2CH2 / CH2=CH2

M2 H2O

Accept in eitheIgnore state syAward 1 markincorrect coeffAccept H4C2 an

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SECTION B


8 a i M1 bubbles / fizzing / effervescence / metal gets smaller / white

trail

Ignore metal d

Reject all answii M1 melts / forms a ball / darts / moves (on surface) / floats Ignore referen

Reject all answ

b i M1 calcium hydroxide

ii M1 NaOH

c M1 hydrogen / H2 Ignore H

M2 (squeaky) pop with burning splint /burns with a (squeaky) pop Accept other lighted spill orReject glowingIgnore referenNo CONSEQ fro

d i M1 blue / purple Ignore qualifie

M2 OH / hydroxide Ignore hydroxy

ii M1 yellow / orange Ignore qualifie/ brightReject all othe

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9 a M1 hydrogen peroxide

M2 manganese(IV) oxide / manganese dioxide

b M1 (gas) syringec M1 catalyst / to speed up the reaction / lower activation energy

d i M1 (s) for both PbS and PbSO4

M2 (aq) for H2O2 and (l) for H2O

ii M1 PbS / lead sulphide / sulphide ion / S2 / sulphur in leadsulphide

Ignore oxidatio

M2 gains oxygen/O/O2increase in oxidation state

only award if Mignore loss of e

e i M1 S + O2 SO2 Ignore state syAccept S2 or S8

ii M1 acidic / (forms) H+ (ions) / sulphurous acid / sulphuric(IV) acid Reject sulphuriii M1 orange

M2 green Accept blue-gr

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10 a M1 electron transfer

M2 from magnesium/Mg to chlorine/Cl

M3 Mg loses two electrons and (each) Cl gains one electron

All marks caannotated diag

Award 0/3 ifelectronsIgnore covalen

M3 dependent

b M1 magnesium / Mg

M2 loss of electrons / increase in oxidation state Ignore numberM2 independen

c M1 + and ions / oppositely charged ions / Mg2+ and Cl Need idea of +

M2 strong (electrostatic) attractions (within lattice) accept strong reject covalen

M3 lot of energy needed to overcome attractions / break bonds /

separate ions

Do not accept

Ignore hard toany mentionintramolecula

So strong inteenergy to over

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11 a i M1 fractional distillation / fractionation

ii M1 crude oil heated M1 given evenOnly M1 possimention cracki

M2 (vapour) passed into column/tower If crude oil hthen give only

M3 fractions collected at different heights

M4 correct reference to boiling point / molecular size /temperature gradient/hot at bottom cooler at top

Do not awagradient is wro

All marks can b

b i M1 bitumen

ii M1 gasoline

iii M1 bitumen

iv M1 refinery gases

M2 fuel oil

Accept answer

Accept naphthc M1 oxygen Ignore air

M2 carbon dioxide

M3 water

Accept answerAccept steam i

All marks in c a

Ignore heat

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d i M1 CnH2n+2 Accept other leaccept CnH2(n+1

ii M1 same/similar chemical properties / same functional group

M2 gradation in physical properties / gradation in specifiedphysical property (eg boiling point)

M3 neighbouring members differ by CH2

reject trend in

reject same/siIgnore refere

references saturation/unsgroupAccept any two

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