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Mark Scheme (Results)
Summer 2013
International GCSEChemistry (4CH0) Paper 1C
Science Double Award (4SC0)
Paper 1C
Edexcel Level 1/Level 2 CertificateChemistry (KCH0) Paper 1CScience (Double Award) (KSC0)
Paper 1C
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Edexcel and BTEC Qualifications
Edexcel and BTEC qualifications come from Pearson, the worlds leading learningcompany. We provide a wide range of qualifications including academic, vocational,occupational and specific programmes for employers. For further information visit ourqualifications websites at www.edexcel.com or www.btec.co.uk for our BTEC
qualifications.Alternatively, you can get in touch with us using the details on our contact us page at
www.edexcel.com/contactus.
If you have any subject specific questions about this specification that require the help
of a subject specialist, you can speak directly to the subject team at Pearson.Their contact details can be found on this link: www.edexcel.com/teachingservices.
You can also use our online Ask the Expert service at www.edexcel.com/ask. You willneed an Edexcel username and password to access this service.
Pearson: helping people progress, everywhere
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Summer 2013
Publications Code UG037094
All the material in this publication is copyright
Pearson Education Ltd 2013
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Question
numberAnswer Notes Ma
1 (a) i 5
ii 11
iii 5
iv 6
v 5
1 (b) i more
ii more
iii the same number of
1 (c) cross in box D (2.8.3)
Total
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Question
numberAnswer Notes M
2 (a) i cross in box A (zinc sulfate)
iicross in box B (iron)
cross in box C (magnesium)
Apply list principle - 3 crosses = max 14 or 5 crosses = 0 marks
2 (b) burns with a pop/squeakORuse burning/lit splint/flame tosee if pop/squeak
Must be reference to test and resultReference to splint/match with noindication of flame is not enoughReject reference to glowing splint
Ignore flame extinguishedSqueaky pop test on its own is not
sufficient
2 (c) 2 (1) 2 Accept multiples and fractions
2 (d) i
ii
cross in box 3
reversible / can go in bothdirections
/ can go backwards andforwards
Ignore references to equilibriumIgnore references to other reactiontypes (e.g. hydration / oxidation /
exothermic)Accept either equation with
Total
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Question
numberAnswer Notes
3 (a) i gas / (g) / g Accept equivalentssuch as gaseous /
vapourIgnore colours
ii darker / dark grey Accept blackIgnore references states
Ignore more intenReject reference to
any other colours
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Questionnumber
Answer Notes
3 (b) i no reaction (possible) / no
displacementOR
halogens do not react withtheir own halide ions
Accept no change
Ignore references to lithium chloride containingchlorine / already reacted / OWTTE
ii
iii
iodine/it is less reactivethan bromine/ bromine more reactivethan iodine
iodine
Accept correct references to positions in (re)activityseriesBoth halogens must be mentioned, except assume refers to iodine
Reject ide endingsAccept symbols and formulae
Ignore references to only one element, e.g. iodine unreactiveReject any comparison involving sodium
Ignore references to states
Ignore I and I2iv
v
cross in box D (brominedisplaces iodine)
2KCl + Br2 Either order
Penalise incorrect symbols/numbers / unconventionformulae in this part, e.g. CL, br, Br2, ClK
To
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Questionnumber
Answer Notes
4 a 4 electrons shared between 2 (carbon)atoms
Ignore inner electronseven if wrong Ignore
number of hydrogenatoms
4 electron pairs between 2C and 4H atoms Accept all permutation
dots and crossesIgnore intersecting cir
Accept H atoms at allanglesAt least one C or one Hatom must be labelled
max 1 if notMax 1 if more than 2 C
atomsMax 1 if wrong numbeelectrons in outer shel
any atom
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Questionnumber
Answer Notes
4 b i setting out correct division of each %byAr
OR3.2, 9.7 and 3.2
Award 0/3 if division by any atomicwrong way up / multiplication used
Do not penalise roundings and minoof % values, eg 38 or 39 for carbonIf molecular masses used for H and
M1, but can award M2 and M3but no CQ in iiUsing 2 and 32 gives C2H3OUsing 1 and 32 gives C2H6O
Using 2 and 16 gives C2H3O2Working required for these answers
division by smallest /ratio of 1 : 3 : 1 M2 subsumes M1
CH3O Accept elements in any orderAward 3 for correct final answer witworkingNo ECF from M2
Accept use of 62 from ii,i.e. 62 0.387 = 24 etc scores M1ratio scores M2, answer scores M3
ii C2H6O2 Accept elements in any order
No other answer acceptable
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Questionnumber
Answer Notes
5 a i haematite Ignore iron oxide / formulae
ii
iii
Al2O3/ Al3+2O23
carbon / C
(positive/negative) electrode
Ignore reactants in equation
Accept graphite
Ignore coke / anthraciteDEP on M1 (including coke or any m
Accept anode / cathodeAccept references to lettingelectrons/electricity/current flowAccept references to letting
electrons/electricity/current in/out
cell/electrolyteIgnore references to attracting ionsAccept references to conducting eleIgnore references to electrolysisIgnore references to burning or com
oxygenIgnore references to reduction/oxid
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Question
number Answer Notes 5 iv oxygen / O2 Accept O
Ignore airproduction of heat/maintaining temperature
of furnaceOR
formation of reducing agent/carbon monoxide
DEP on mention of
oxygen/O2/O/airIgnore
combustion/oxidation/reof carbon/cokeIgnore references toincreasing temperature o
furnace
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Question
numberAnswer Notes
5 (b) i redox
ii
iii
(it/ Al3+/aluminium ions) gain of electron(s)OR
Al3+combines/reacts with electrons
C / carbon
gain of oxygen / O / O2OR
reacts/combines/joins/bonds with oxygenor O or O2ORreduces water/H2O
Reject gain of electronby Al/aluminium
Accept decrease in
oxidation stateIgnore/ references to gof oxygen
Accept graphite/coke
DEP on M1Ignore forms carbon
monoxideIgnore references to loof electronsAccept increase in
oxidation stateIgnore (acts as) reduciagent
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Question
numberAnswer Notes M
5 c i (a substance that)increases rate of reaction /
speeds up reaction /decreases time of reactionis (chemically) unchanged(at the end)
ORmass does not change
Accept is not used up / does not changeAccept reference to lowering activation
energyIgnore reference to alternative route
Ignore references to yieldIgnore reference to not reacting or takingpart in reactionReject reference to providing/increasing
energy
Reject reference to incorrect statement suchas removes impurities
ii (acts as) solvent (foralumina/aluminium oxide)
ORto lower the (operating)temperature
Accept to lower melting point (ofmixture/electrolyte)
Reject to lower melting point ofalumina/aluminiumoxide/aluminium/bauxiteAccept to reduce (heat) energy requirement
Accept to increase the conductivity of themixture/electrolyte/alumina
Reject acts as a catalyst
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Questionnumber
Answer Notes Ma
5 d i Fe2O3 + 3CO 2Fe + 3CO2 M1 for correct reactants
and products
M2 for balancing
M2 dep on M1
ii neutralisation Accept acid-base
Ignore all otherdescriptions
iii slag
Total 1
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Question
numberAnswer Notes M
6 (a) C Accept formula of C
6 (b) i (compound/molecule/substancecontaining) carbon and hydrogen
(atoms/elements)
Reject atom/element in place ofcompound/molecule
Reject compound/molecule in place ofatoms/elements
Reject mixture
Only
A
M2 dependent on mention of carbonand hydrogen even if M1 not awarded
Accept other terms with samemeaning, e.g. solely / exclusively /just
M3 independentAccept name/formula of A
ii contains a (C=C) double bond Accept multiple bond
Ignore references to type ofcompound, eg hydrocarbon
Reject double bond between C and HDo not penalise incorrect terms suchas atom or elementIgnore not all bonds are single
Accept can undergo addition reactionsAccept does not contain the
maximum number ofhydrogens/hydrogen atoms
B M2 independent
Accept name/formula of B
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Answer Notes M
6 b iii (compounds / molecules / substances with)
same molecular formula / same number ofeach type of atom
Ignore same (chemical)
formula /same compoundNo penalty for reference tohydrocarbons
Reject sameempirical/general formulaIf atoms or elements insteadof compounds or molecules,
only 1 of M1 and M2 can beawarded
different structures/different structural/displayed formulaeOR
atoms arranged differently
Ignore different moleculararrangement
C and F Accept in either orderAccept formulae of C and F
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Questionnumber
Answer Notes
6 c i same/similar chemical
properties/reactions/behaviour/characteristics
Ignore specific examples such
with oxygenIgnore similar (type of) reactiv
Do not penalise reference to tr
gradation / gradual change / trend / increase
/ decrease of physical properties
Accept reference to specific pr
boiling pointReject same / similar physical Ignore variable physical prope
same functional group Ignore reference to specific gr
same general formula Accept alkanes have the (geneCnH2n+2Reject same empirical/molecu
Any two for 1 each
Accept two answers on one anIgnore any reference to propespecified as physical or chemic
ii D AND E Reject any other combinations
Accept correct formulae
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Questionnumber
Answer Notes
7 a reference to line/curve/temperature
/graph/itANDnot reached minimum / not constant / not
level/not horizontal /still falling/decreasing/changing
Ignore reference to correlation
Ignore has not reached zero / Ignore does not become
b (better) insulator (than glass)ORpoor conductor (of heat)
Accept equivalents such as preentering / keeps out heat betteAllow stops heat escaping / tra
Reject references to keeping teIgnore references to breaking
c i effervescence / fizzing / bubbles
ORcolourless solution/liquid formed
Accept carbon dioxide gas
Accept gas given off/evolved/fIgnore identity of gasAccept solid disappears/dissolv
Ignore hissing and other sound
ii Neutralisation Accept acid-base / acid-alkali
endothermic M1 and M2 independentAccept answers in either order
Do not penalise contradictions and endothermic this answer
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Question
numberAnswer Notes
7 d i product formulae or names /products (word) above
reactants
Horizontal line not neededIgnore formula errors and one or
two missing product(s)Ignore curves and intermediates
ii (approximately) vertical line
between reactants andproducts / between two levelsAND
labelled H/ energy change /heat change / enthalpy change
Ignore arrowheads on vertical line
Ignore sign of HMark can be awarded forexothermic reaction
Accept 2310 or any other numberin place of H
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Questionnumber
Answer Notes
7 (e) i temperature change = ()5.5(C)
Award M1 for 5.5 anywhere
heat change (= 100 4.2 5.5) = 2310/2300 (J)
CQ on candidate temperaturechange, provided other values
correctAccept answer in kJ
Ignore signsCorrect final answer scores 22.31 (J) scores 1 mark if M1 notawarded
ii concentration (of vinegar /(ethanoic) acid / CH3COOH)
Ignore strengthIgnore reference to MrAccept concentration even if in anincorrect expression
Total
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Questionnumber
Answer Notes
8 (a) mass Accept weight surface area / size / volume Ignore length / width / height /
thickness / shape / typeIgnore temperature / purity /
density
8 (b) (2) time / how long (to
collect gas)
(3) number of / how many(marble) chips
(4) volume of gas / how
much gas collected
(5) percentage /concentration (of acid)
Accept length of
reaction/experiment
Ignore amount of marbleAccept amount of (marble) chips
Accept carbon dioxide/CO2in place
of gasAccept amount of gas
Accept strength (of acid)
Ignore volume of acidReject amount (of acid)
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Questionnumber
Answer Notes
8 (c) i all six points plotted to nearest
gridline
Deduct 1 mark for each error up to ma
extra points, but no penalty for point a
straight line of best fit Line need not be extrapolated
Must be drawn with a rulerCQ on candidates plotted points
ii anomalous point circled at 1.5, 20 or CQ on candidates line of
iii timer started late / stopped early
concentration/% too high/more
than 20%marble chips bigger / moremarble chipsair in measuring cylinder before
experiment started(room) temperature higher
Ignore just wrong time
Ignore just wrong concentration
Ignore just wrong mass/size
Accept smaller volume of gas collected
vertical line from 50% to drawngraph line
2.4 (cm3/s)
Ignore references to calculation
Any two for 1 mark eachM1 to M5 CQ on position of anomalous anomalous point below line of best fit,
M1 timer started too early/stopped too M2 concentration/% too low/less than M3 marble chips smaller / fewer marbleM4 larger volume of gas collected
M5 (room) temperature lower
Accept short vertical line crossing graphAccept point on graph line at 50%
CQ on drawn graph line but can be awavertical line
Do not penalise incorrect units
iv
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Questionnumber
Answer Notes
9 (a) i beaker Ignore qualifiers such as measuring/ graduated / 250 cm3
ii Pipette Ignore qualifiers such as measuring/ graduated / 25 cm3
iii colour change is gradual /notsharp/not definedOR
end point not sharp/defined/accurate
methyl orange / phenolphthalein /litmus
Ignore reference to many colours
Accept other correct indicatorsIgnore reference to pH meterReject litmus paperIgnore named colours and colour ch
iv (measures) only one volume / fixedvolume / 25 cm3
has only one graduation markORcannot deliver (measured) variablevolume
ORvolume required is not knownOR
cannot be controlled / hard to control
Ignore reference to accuracy / sizeAccept reverse arguments based on
burette, eg burette can deliver/meavolume
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Questionnumber
Answer Notes
9 (b) (after) 22.60
(before) 2.75
(added) 19.85 CQ on before and after readingsAward 1 for before and after
values both correct but in wrongorderAll values must be to 2 dpPenalise answers to other than 2
dp once only
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Questionnumber
Answer Notes
9 (c) i ticks in columns 3 and 4
ii 23.35 + 23.452
CQ on ticked resultsIf no results ticked, award M1 if
only columns 3 and 4 averagedIf only 1 result ticked, then nomarks can be awarded in (c)
23.4(0) CQ on results averaged
Answer should be to 2 dp, exceptthat trailing zero not needed
Correct final answer withoutworking scores 2
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Questionnumber
Answer Notes
9 (d) i divide/ by 1000 (not by
100)OR
convert volume/cm3to dm3OR
use 1000 instead of 100
Accept 0.0500 23.60 (=
0.00118 mol)1000
Accept divide (final) answer by 10
ii multiply/ (amount of H2SO4)by 2 (not divide by 2)
Accept 0.(0)0118 2 (=0.0(0)236 mol)Accept any other number in place
of 0.0(0)118Accept multiply (final) answer by 4
iii divide by 25.0 (not by 23.60)ORdivide by volume of KOH (not
by volume of H2SO4)OR
use 25.0/volume of KOHinstead of 23.60/volume ofH2SO4
Accept 0.00590 1000 (= 0.236mol)
25.0
Accept any other number in placeof 0.00590
Must be positive statement about
correction needed, e.g. in iii,ignore statement about volume of
H2SO4should not have been used
Total
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Question
numberAnswer Notes
10 (a) air / atmosphere
10 (b) i (equilibrium / it) shiftsto left/reactants
Accept favours reverse reactionAccept less product/ CO + (3)H2/ lower yield
Accept more reactant / CH4+ H2Ofewer (gas)
moles/molecules onleftORfavours side with fewer
moles/molecules
Accept opposite arguments, eg more moles
rightIgnore references to volume and pressureAccept references to particles in place ofmolecules
Reject atoms in place of moleculesIgnore references to rate / collisions
If wrong shift, M2 cannot be awardedIf no shift, M2 can be awardedMarks can be awarded for both points in eithprediction or reason
ii (equilibrium / it) shifts
to left/reactants
Accept favours reverse reaction/less produc
Accept less product/ CO2+ H2/ lower yieldAccept more reactant / CO + H2O
(forward) reaction
exothermicORreverse reaction
endothermicIgnore references to rate
If wrong shift, M2 cannot be awardedIf no shift, M2 can be awardedMarks can be awarded for both points in eithprediction or reason
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Questionnumber
Answer Notes
10 (c) Increased (rate) Accept alternatives such as fasterreactions
Increased (rate) Accept alternatives such as faster
reactions
Ignore references toequilibrium/yield
Ignore references to forward andreverse reactions
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Questionnumber
Answer Notes
10 d i Mr(NH4NO3) = 80 Award M1 for 80 anywhere n (= 40000 )= 500 (mol)
80
ECF from incorrect Mr
500 scores M1 and M20.5 (mol) scores only M1
ii Answer to di / 500 (mol)
iii Mr(NH3) = 17 Award M1 for 17 anywhere, exceptif result of incorrect calculation
m = 500 17 = 8.5 (kg)1000
ECF from incorrect MrMoles CQ on ii
Accept answer in g if unit is givenIf no conversion from kg to g in i,and no conversion from g to kg iniii, penalise these errors once only
Award 2 marks for 8.5 (kg)
10 e phosphorus AND potassium Accept in either order
Ignore symbolsReject phosphate/phosphine
Total
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Questionnumber
Answer Notes
11 a i delocalised electrons / sea ofelectrons
Ignore free electrons
move / flow (throughstructure) / mobile (whenvoltage/potential difference
applied)
M2 needs mention of electrons,e.g. "electrons move/flow" scoresM2 but not M1
Ignore references to carryingcharge/currentNo penalty for references toaluminium atoms or ions / nuclei /
protons, but any mention of thesemoving = 0/2
ii layers/sheets/planes/rowsAND(positive)
ions/atoms/particles
Reject
molecules/protons/electrons/nuclei
slide (over each other) Allowslip/flow/shift/roll/move/OWTTE inplace of slideDo not award M2 if no mention of
layers or equivalentDo not award M2 if
protons/electrons/nuclei
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Question
numberAnswer Notes
11 b NITROGEN
(simple) molecular structure Accept (nitrogen/N2/small/discrete) molecu
intermolecular forces (of
attraction)/ forces between molecules
Accept intermolecular bonds
Reference to intermolecular also scores M1
weak / easily overcome
/need little energy toovercome
If any reference to breaking covalent bondsany other type of bonding, only M1 can beawarded
SILICA
giant (structure) Accept macromolecularIgnore lattice
covalent (bonds) Covalent can be anywhere in answer
bonds strong / hard to break/need a lot of energy to break
If any reference to breaking intermolecularforces or any other type of bonding, only Mcan be awardedAny five for 1 mark each
TTotal for pa
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Further copies of this publication are available from
Edexcel Publications, Adamsway, Mansfield, Notts, NG18 4FN
Telephone 01623 467467
Fax 01623 450481
Email [email protected]
Order Code UG037094 Summer 2013
For more information on Edexcel qualifications, please visit our website
www.edexcel.com
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