i
Mark Schemes Summer 2008
IGCSE
IGCSE Chemist ry (4335)
Edexcel Limit ed. Regist ered in England and Wales No. 4496750 Regist ered Of f ice: One90 High Holborn, London WC1V 7BH
ii
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Summer 2008
Publ icat ions Code UG020251
Al l t he mat erial in t his publ icat ion is copyright
© Edexcel Lt d 2008
iii
Contents
1. 4335-1F Mark Scheme 1
2. 4335-2H Mark Scheme 11
3. 4335-03 Mark Scheme 19
-1-
4335 IGCSE Chemistry Summer 2008
IGCSE CHEMISTRY 4335-1F MARK SCHEME
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
1 (a)
second box
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
1 (b)(i)
t op box
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
1 (b)(ii)
middle box
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
1 (c)(i)
made up of / cont ains only one t ype of
at om
or
somet hing t hat cannot be broken
down by chemical means
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
1 (c)(ii)
t hree/ 3
(1)
(Total 5 marks)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
2 (a)(i)
magnesium
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
2 (a)(ii)
gold
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
2 (b)(i)
magnesium/ zinc is more react ive t han
iron
OR
magnesium displaces iron
(1)
-2-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
2 (b)(ii)
zinc sulphat e AND iron
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
2 (c)(i)
bulb / ammet er/ buzzer
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
2 (c)(ii)
ions
(1)
(Total 6 marks)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (a)(i)
l ight ed spil l
pop (dependent on correct t est )
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (a)(ii)
sodium hydroxide
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (a)(iii)
green
blue/ purple
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (b)
loses
gains (give one mark if t he f irst t wo are
t he wrong way round)
high
st rong (dependent on having high
correct )
1
1
1
1
(4)
(Total 9 marks)
-3-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (a)(i)
bit umen
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (a)(ii)
ref inery gases
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (a)(iii)
gasol ine
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (b)
kerosene
diesel/ gasol ine/ ref inery gases
bit umen
1
1
1
(3)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (c)(i)
oxygen on lef t
wat er on right
carbon dioxide on right
1
1
1
(3)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (c)(ii)
carbon monoxide
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (c)(iii)
carbon
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (d)(i)
giant
momomers
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (d)(ii)
middle box
(1)
(Total 14 marks)
-4-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
5 (a)(i)
f i f t h / last box
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
5 (a)(ii)
A E C D – ful ly correct get s t hree
marks.
If not ful ly correct t hen (t o a
maximum of t wo):
bot h A and E before C – 1 mark
D direct ly af t er C – 1 mark
E direct ly before C – 1 mark
(3)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
5 (a)(iii)
heat / warm
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
5 (b)(i)
yel low
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
5 (b)(ii)
red
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
5 (b)(iii)
neut ral isat ion
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
5 (b)(iv)
wat er
(1)
(Total 9 marks)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
6 (a)
f irst box: nit rogen
second box: oxygen
t hird box: argon; carbon dioxide.
one mark per gas in correct box. If
gas used t wice t hen no mark for t hat
gas.
(4)
-5-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
6 (b)(i)
black
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
6 (b)(ii)
CuO
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
6 (c)(i)
t op box: hydrochloric acid
bot t om box: calcium carbonat e
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
6 (c)(ii)
l imewat er/ calcium hydroxide
(solut ion)
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
6 (c)(iii)
f ire ext inguisher / f izzy drinks / dry
ice as coolant or st age ef fect s
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
6 (d)(i)
carbon
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
6 (d)(ii)
magnesium
(1)
(Total 12 marks)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
7 (a)(i) elect rolysis
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
7 (a)(ii) graphit e / carbon
(1)
-6-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
7 (a)(iii) – on lef t and + on right
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
7 (a)(iv) aluminium oxide / alumina
cryol it e
accept
correct
formulae
ignore
bauxit e
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
7 (a)(v) elect ricit y (ignore qual if icat ions) /
elect rical energy (not energy
alone)
Anode/
posit ive
elect rode
replacement
Cat hode
/ elect rode
replacement
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
7 (b)(i) oxygen
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
7 (b)(ii) • carbon dioxide / carbon monoxide
• graphit e/ carbon/ elect rode
oxidised/ burned/ react s wit h
oxygen
accept
correct
formulae
(ignore
lower case)
l ist s
equat ion
1
1
(2)
(Total 9 marks)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
8 (a)(i) Any t wo f rom:
• same or similar chemical
propert ies / same funct ional group
• gradat ion in physical propert ies
• neighbouring/ successive members
dif fer by CH2
Gradat ion of
specif ied
physical
propert y (eg:
boil ing
point / bp(t ),
melt ing
point / mp(t ),
viscosit y)
NOT a
specif ied
chemical
propert y
dif ferent /
same
physical
propert ies (2)
-7-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
8 (a)(ii) alkene
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
8 (a)(iii) CnH2n Any ot her
let t er in place
of “ n”
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
8 (b)(i) • (H) one elect ron shown
• (C) t wo elect rons in f irst shel l and
four in second shel l
Accept any
symbol for
elect rons.
Elect rons
on nucleus
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
8 (b)(ii) • al l f ive at oms and four shared pairs
of elect rons
• no ext ra out er elect rons.
IGNORE inner
elect rons
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
8 (b)(iii) t et rahedral
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
8 (c)(i) • (compounds wit h) same molecular
formula
• (but ) dif ferent st ruct ural formulae
/ displayed formula/ st ruct ure /
at oms arranged dif ferent ly
(same) element s = 0 marks
Mark
independent ly
same
chemical
formula
Rej ect
subst ances
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
8 (c)(ii) Correct st ruct ures of but ane and
met hylpropane. ALL bonds shown
Penal ise st icks wit h missing H once
only
1
1
(2)
(Total 13 marks)
-8-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
9 (a)(i) 2
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
9 (a)(ii) 2.8.2
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
9 (b)(i) any t wo f rom
• ef fervescence / f izzing / bubbles
• cloudiness / whit e precipit at e
/ milky / whit e suspension
• Ca get smaller / disappears (ignore
dissolves).
• Ca moves up and down
Ignore gas
made
ignore
f loat s/ moves
List
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
9 (b)(ii) Ca(OH)2
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
9 (b)(iii) • blue
• alkal i / OH- / hydroxide / pH >7
(ignore base)
• st at ed pH value in range 8-14
purple 1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
9 (c)(i) • grey / si lver(y)
• whit e
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
9 (c)(ii) any t wo f rom
• over/ t hrough wat er / downward
displacement of wat er
• (gas) syringe
• upward del ivery / downward
displacement of air
a descript ion
of t his
suit able
diagrams
gas cyl inder
(2)
-9-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
9 (c)(iii) hydrogen + oxygen → wat er / st eam ignore heat formulae
(1)
(Total 12 marks)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
10 (a)(i) ammonia / NH3 Ammonium
NH4 (1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
10 (a)(ii) chloride / Cl-
Chlorine
Cl
Cl2 (1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
10 (a)(iii) copper(II) / Cu2+
/ copper / cupric cupper Copper(I)
Cuprous
Cu+ (1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
10 (a)(iv) iron(II) / Fe2+
/ ferrous Fe3+
Ferric
Iron (1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
10 (b)(i) CuSO4 / copper((II)) sulphat e
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
10 (b)(ii) • KNO3 / pot assium nit rat e
• l i lac (dependent on correct
compound)
OR
• CuSO4 / copper((II)) sulphat e
• green / blue-green (dependent on
correct compound)
pot assium/ C
pink
copper/ B
Purple
blue
(2)
-10-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
10 (c)(i) yel low precipitate/ ppt/ ppte suspension
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
10 (c)(ii) AgNO3(aq) + LiI(aq) → AgI(s) + LiNO3(aq)
LiI(aq) + AgNO3(aq)
formulae of product s
st at e symbols of product s (dependent on
correct product formulae)
i f al l correct
but balanced
wrongly, award
2 marks
(3)
(Total 11 marks)
PAPER TOTAL 100 MARKS
-11-
4335 IGCSE Chemistry Summer 2008
IGCSE CHEMISTRY 4335-2H MARK SCHEME
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
1 (a)(i) elect rolysis
(1)
1 (a)(ii) graphit e / carbon
(1)
1 (a)(iii) – on lef t and + on right
(1)
1 (a)(iv) aluminium oxide / alumina
cryol it e
accept correct
formulae
ignore bauxit e
1
1
(2)
1 (a)(v) elect ricit y (ignore qual if icat ions)
/ elect rical energy (not energy
alone)
anode/ posit ive
elect rode
replacement
cat hode
/ elect rode
replacement (1)
1 (b)(i) oxygen
(1)
1 (b)(ii) • carbon dioxide / carbon
monoxide
• graphit e/ carbon/ elect rode
oxidised/ burned/ react s wit h
oxygen
accept correct
formulae (ignore
lower case)
l ist s
equat ion
1
1
(2)
9
2 (a)(i) Any t wo f rom:
• same or similar chemical
propert ies / same funct ional
group
• gradat ion in physical propert ies
• neighbouring/ successive
members dif fer by CH2
gradat ion of
specif ied physical
propert y (eg:
boil ing
point / bp(t ),
melt ing
point / mp(t ),
viscosit y)
NOT a
specif ied
chemical
propert y
dif ferent /
same
physical
propert ies
(2)
2 (a)(ii) alkene
(1)
2 (a)(iii) CnH2n any ot her let t er
in place of “ n”
(1)
2 (b)(i) • (H) one elect ron shown
• (C) t wo elect rons in f irst shel l
and four in second shel l
aAccept any
symbol for
elect rons.
elect rons on
nucleus
1
1
(2)
2 (b)(ii) • al l f ive at oms and four shared
pairs of elect rons
• no ext ra out er elect rons.
IGNORE inner
elect rons
1
1
(2)
2 (b)(iii) t et rahedral
(1)
-12-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
2 (c)(i) • (compounds wit h) same
molecular formula
• (but ) dif ferent st ruct ural
formulae / displayed
formula/ st ruct ure / at oms
arranged dif ferent ly
(same) element s = 0 marks
mark
independent ly
same
chemical
formula.
Rej ect
subst ances.
1
1
(2)
2 (c)(ii) Correct st ruct ures of but ane and
met hylpropane. ALL bonds shown
Penal ise st icks wit h missing H
once only
1
1
(2)
13
3 (a)(i) 2
(1)
3 (a)(ii) 2.8.2
(1)
3 (b)(i) any t wo f rom
• ef fervescence / f izzing /
bubbles
• cloudiness / whit e precipit at e
/ milky / whit e suspension
• Ca get smaller / disappears
(ignore dissolves).
• Ca moves up and down
ignore gas made
ignore
f loat s/ moves
List
(2)
3 (b)(ii) Ca(OH)2
(1)
3 (b)(iii) • blue
• alkal i / OH- / hydroxide / pH >7
(ignore base)
• st at ed pH value in range 8-14
purple 1
1
(2)
3 (c)(i) • grey / si lver(y)
• whit e
1
1
(2)
3 (c)(ii) any t wo f rom
• over/ t hrough wat er / downward
displacement of wat er
• (gas) syringe
• upward del ivery / downward
displacement of air
a descript ion of
t his
suit able diagrams
gas cyl inder
(2)
3 (c)(iii) hydrogen + oxygen → wat er /
st eam
ignore heat formulae
(1)
12
4 (a)(i) ammonia / NH3 ammonium
NH4 (1)
-13-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (a)(ii) chloride / Cl-
chlorine
Cl
Cl2 (1)
4 (a)(iii) copper(II) / Cu2+
/ copper / cupric cupper copper(I)
cuprous
Cu+ (1)
4 (a)(iv) iron(II) / Fe2+
/ ferrous Fe3+
ferric
iron (1)
4 (b)(i) CuSO4 / copper((II)) sulphat e
(1)
4 (b)(ii) • KNO3 / pot assium nit rat e
• l i lac (dependent on correct
compound)
OR
• CuSO4 / copper((II)) sulphat e
• green / blue-green (dependent
on correct compound)
pot assium/ C
pink
copper/ B
purple
blue
(2)
4 (c)(i) yel low precipitate/ ppt/ ppte suspension
(1)
4 (c)(ii) AgNO3(aq) + LiI(aq) → AgI(s) +
LiNO3(aq)
LiI(aq) + AgNO3(aq)
formulae of product s
st at e symbols of product s
(dependent on correct product
formulae)
i f al l correct but
balanced
wrongly, award 2
marks
(3)
11
5 (a)(i) dif fusion
(1)
5 (a)(ii) • ment ion of part icles (if part icles
named, must be correct ) in
correct cont ext
• moving (randomly)
(accept
molecules/ ions)
move (f rom high
t o low
concent rat ion)
1
1
(2)
5 (b)(i) • (blue) ppt – colour not needed
but penal ise ppt if colour is
wrong
• deep/ dark/ royal blue
• solut ion / dissolves
ignore changes t o
colour of solut ion
dark/ royal/
deep blue
ppt
1
1
1
(3)
5 (b)(ii) [Cu(H2O)2(NH3)4]2+
/
[Cu(NH3)4(H2O)2]2+
formulae wit hout
[ ]
(1)
7
-14-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
6 (a)(i) Any t hree f rom
• f loat / on surface
• f izz/ bubble (ignore gas)
• move/ dart about
• melt / form sphere/ bal l
• Na get s smaller / disappears
(ignore dissolves)
ignore references
t o f lames /
ignit ing
(3)
6 (a)(ii) 2Na + 2H2O 2 NaOH + H2
• correct formulae
• balancing (dependent on f irst
mark being awarded)
Na(OH)
any mult iple
(2)
6 (a)(iii) Moves/ bubbles fast er/ (more)
violent / more vigorous/ cat ches
f ire/ f lame/ explodes
react ion
fast er/ i t is
fast er (1)
6 (b)(i) • sodium loses elect ron(s)
• oxygen gains elect rons
• correct number of elect rons for
each at om
marks could be gained by
suit able addit ions t o print ed
diagram
indicat ion of 2 Na
and 1 O
any
reference t o
sharing
/ covalent
gives O
(3)
6 (b)(ii) • st rong at t ract ive forces / bonds
(regardless of what t hese are
bet ween)
• bet ween ions
• require a lot of energy t o
overcome / dif f icul t t o break
(regardless of what t hese are
bet ween)
second mark
not given if
at oms /
molecules /
int ermolecul
ar
1
1
1
(3)
6 (b)(iii) • st ronger at t ract ive forces /
bonding
• magnesium ion 2+, sodium ion
1+ / magnesium loses 2 elect rons,
sodium loses 1
elect ron/ magnesium ions are
smaller or have bigger charge or
are more highly charged (must
st at e or imply comparison
bet ween Mg and Na)
ignore more
bonds/
int ermolecular
forces
MgO Covalent
= 0
delocal ised
elect rons = 0
1
1
(2)
14
-15-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
7 (a) any f ive f rom:
• add magnesium carbonat e t o
acid
• st ir/ mix
• excess magnesium carbonat e
• f i l t er / cent rifuge and decant
• heat or evaporat e f i l t rat e and
st op evaporat ion at a suit able
point / heat f i l t rat e and leave t o
cool / leave f i l t rat e t o evaporat e
or t o cryst al l ise or for suit able
t ime / place in oven below 100 °C
• dry cryst als wit h (f i l t er) paper
/ desiccat or
Ignore indicat ors
• If use sodium
carbonat e (or
ot her soluble
carbonat e)only
point s 2,5,6
• If use ot her
insoluble
carbonat e, al l
bar f irst point .
• Wrong met hod
of prep. Then get
5 and 6 only.
heat t o
dryness, can
not get 5 or 6
(5)
7 (b)(i) • colourless
• t o pink
i f j ust st at e
“ pink” wit h no
st art colour, t hen
score 1
purple / red
1
1
(2)
7 (b)(ii)
• 0.150 x 0.00870
• =0.00131 correct answer scores
2
(moles)
incorrect or
fai lure t o convert
volume t o dm3
gives max 1
accept 2 t o 4 sig
f igs
(0.001305)
wrong
numbers
used = 0
1
1
(2)
7 (b)(iii) (i i) ÷ 2 = 0.000653
(moles)
cq on b(i i)
accept 2 t o 4 sig
f igs
(0.006525)
(1)
7 (b)(iv) (i i i) ÷ 0.025 = 0.0261
(mol dm-3
)
cq on b(i i i )
accept 2 t o 4 sig
f igs
(0.02612)
(1)
11
8 (a)(i) • add (named) acid
• bubbles/ ef fervescence/ f izzing
OR gas produced t urns l imewat er
milky
2nd
mark possible
only if acid
added
1
1
(2)
8 (a)(ii) 2NaOH + CO2 Na2CO3 + H2O
formulae = 1
balancing = 1 (only if f ormulae
correct )
accept any
mult iple
(2)
8 (b) • no change / remains clear
• carbon dioxide react ed
/ removed(by sodium hydroxide) /
formed sodium carbonat e /
1
1
(2)
-16-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
8 (c)(i) • Mr NaHCO3 = 84
• moles = 4.2 ÷ 84
• = 0.05(0) ignore any unit s
Correct answer scores 3
If Mr incorrect , max 2 (107 gives
0.039; 168 gives 0.025)
1
1
1
(3)
8 (c)(ii) (i) ÷ 2 = 0.025
ignore any unit s
cq
(1)
8 (c)(iii) (i i) x 24 (dm3) =0.6 unit not
required but penal ise incorrect
unit s.
cq answer in
cm3
(1)
11
9 (a) any in range 40 t o 100
(1)
9 (b)(i) H2 + Cl2 2HCl
formulae = 1
balancing = 1 (only if f ormulae
correct ) accept any mult iples
CL
(2)
9 (b)(ii) wat er:
• paper becomes red (NOT
orange)
• acidic / H+ ions produced
met hylbenzene:
• no change / orange
• no H+ ions formed / not acidic
/ does not ionise (indep. of
colour)
red/ orange
ignore refs t o
being neut ral
orange
Ionizes alone
green
references t o
acidit y of
met hyl
benzene
1
1
1
1
(4)
7
10 (a)(i) galvanising / sacrif icial
prot ect ion
(1)
10 (a)(ii) rai l ings / cars / bridges / bucket s
/ wat ering cans / lamp post s et c.
accept
ships/ boat s even
t hough zinc
blocks and not a
cont inuous layer
used
bikes
(1)
10 (a)(iii) • zinc more react ive (t han iron)
• zinc react s/ corrodes/ oxidises in
preference t o / before / inst ead of
iron
It is more
react ive t han
iron
It is more
react ive
zinc rust s
prot ect ive
coat ing of
zinc oxide
1
1
(2)
-17-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
10 (b) • make solut ion of nickel nit rat e
• add met al
• i f react ion occurs t hen met al is
more react ive t han nickel
OR
• work down f rom t op of l ist unt i l
no react ion occurs / work up
f rom bot t om of l ist unt i l react ion
does occur.
displacement
react ion wit hout
making a solut ion
is max 2
react ion wit h
anyt hing else
(such as
HCl(aq)) is
zero
react wit h
met al (for 2nd
mark)
1
1
1
(3)
10 (c)(i) Reduced because gain of
elect rons
reduced because
oxidat ion st at e
decreases
(1)
10 (c)(ii) • Q=1.5 x 160 = 240(coulombs)
• Faradays = 240÷96000 = 0.0025
(cq)
• Moles Ni = 0.0025÷2 = 0.00125
(cq)
• mass Ni = 0.00125 x 59 = 0.074
(g) (0.0737 or 0.07375) (cq).
(0.0025 x 59 is max 3) unit s not
required
Final answer correct = 4 marks
Accept 2 or more
sig f igs (1 sig f ig
max 3)
Accept use of
96500
0.00249
0.001245
0.07337
incorrect use
of kg or mg
1
1
1
1
(4)
12
11 (a)(i) • appropriat e cat alyst
alumina/ aluminium oxide/ porous
pot / (conc) phosphoric acid / conc
sulphuric acid. )
• heat / high t emperat ure
ignore references
t o pressure
150 – 1000oC
aluminium 1
1
(2)
11 (a)(ii) • correct energy level for
endot hermic (higher) and one
f rom
• product s marked wit h correct
names/ formulae
Mark independent ly
Ignore any
act ivat ion
energies shown
1
1
(2)
11 (a)(iii) • Increased
• endot hermic (lef t t o right ) or
descript ion of endot hermic / ΔH
is posit ive
ignore references
t o rat e
if decreased
or st ays t he
same = zero
1
1
(2)
-18-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
11 (b)
• correct st ruct ure wit h minimum
4 carbons
• cont inuat ion bonds shown (not
j ust dot s) (bracket s not required)
Ignore “ n”
subscript s
any st ruct ure
wit h C=C or
based on
wrong repeat
unit = 0
1
1
(2)
11 (c) If calculat e empirical f irst :
• Correct empirical formula wit h
some correct working = 3
division
by Ar
38.7/ 12
= 3.23
9.70/ 1
= 9.70
51.6 /
16 =
3.23
division
by
smallest
3.23 /
3.23 = 1
9.70 /
3.23 = 3
3.23 /
3.23 = 1
empiric
al
CH3O
• Correct molecular formula (wit h
any correct working)= 2
mass of empirical 31
molecular C2H6O2
If calculat e molecular f irst
mass of
each
element
38.7 x
.62 = 24
9.70 x
62 = 6
51.6 x
.62 = 32
division
by Ar
24 / 12
= 2
6 / 1 =
6
32 / 16
= 2
C2H6O2
correct molecular wit h some
working = 3
Correct empirical = 2
If Ar incorrect /
use Z in place of
Ar t hen lose f irst
mark
If NO working
shown, t hen max
1 each for t he
t wo answers
regardless of
order of answers
If f irst st ep
t ot al ly
wrong, zero.
1
1
1
2
1
1
1
2
(5)
13
PAPER TOTAL 120 MARKS
-19-
4335 IGCSE Chemistry Summer 2008
IGCSE CHEMISTRY 4335-03 MARK SCHEME
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
1 (a)
B
E
D
F
b
e
d
f
Any ot her
answers
1
1
1
1
(4)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
1 (b)
F
A
C
f
a
c
Any ot her
answers
(1)
(Total 5 marks)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
2 (a) 22.65
1.30 (zero needed for mark)
21.35
1
1
1
(3)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
2 (b) (i) t icks under 23.10 and 23.20
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
2 (b) (i i) 23.10 + 23.20
2
23.15 (answer must be t o 2 dp)
1
1
(2)
(Total 6 marks)
-20-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (a) mass / weight / amount / number of
moles
(surface) area / size (of chips)
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (b) (i) 3
did not do experiment for 1 minut e
/ did not record t ime
/ wait ed for bubbles t o st op
/ wait ed for react ion t o end
OWTTE
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (b) (i i) t wo correct column headings:
concent rat ion (of acid)
mass of gas lost / given of f
carbon dioxide/ CO2
t wo correct unit s:
%
g / grams
weight
amount
1
1
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (b) (i i) six values correct ly insert ed 2
(4)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (c) (i) vert ical scale of 1 cm rep 0.1 g
six point s correct ly plot t ed
(st raight ) l ine of best f i t ignoring
anomalous point
1
2
1
(4)
-21-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (c) (i i) 0.44 / 50 circled or ot herwise ident if ied 1
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (c) (i i i) cot t on wool not put in f lask/
acid (spray)
escaped
acid t oo concent rat ed / t oo much acid
t emperat ure t oo high
gas col lect ed for longer t han 1 minut e
malachit e pieces smaller /
bigger surface area
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (c) (iv) vert ical l ine f rom 70 % t o l ine of best f i t
0.47
bet ween
0.46 and
0.48
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (d) (i) mass (of CO2 given of f ) increases as
concent rat ion (of acid) increases /
mass (of CO2 given of f ) decreases as
concent rat ion (of acid) decreases
direct proport ion / equivalent wording
such as "mass doubles when
concent rat ion doubles"
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
3 (d) (i i) more col l isions bet ween part icles /
equivalent wording such as "part icles
bump int o each ot her more"
correct reference t o f requency or t ime,
eg "col l isions are more f requent ",
part icles bump int o each ot her more
of t en", "more col l isions in a given t ime"
references
t o energy
1
1
(2)
(Total 21 marks)
-22-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (a)(i)
40.5 40,5
40.50
40,50
Any
ot her
answers
(1)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (a)(ii)
10.5
16.8
10.50
16.80
Any ot her
answers
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (a)(iii)
100 × 10.5
16.8
62.5
cq on 4(a)(i i)
1
1
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (b) (i)
six point s correct ly plot t ed
smoot h curve of best f i t
2
1
(3)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (b) (i i) SEE NOTES
(1)
Notes • If a vert ical l ine is drawn f rom t he int ersect ion (wit hin 1 small
square), t hen award mark if t he answer is wit hin 1 ºC
• If no vert ical l ine drawn f rom t he int ersect ion, t hen decide what t he
answer should be, and award mark if wit hin 1ºC
• Ignore ° C
Quest ion
Number
Correct
Answer
Accept able Answers Rej ect Mark
4 (c)
(solubil i t y)
st ays t he
same
increase(d)
decrease(d)
Any ot her answers wit h t he same
meaning, eg for "st ays t he same",
accept
unchanged, does not change,
remains const ant
eg for "increased", accept
bigger, great er, larger, more
eg for "decreased", accept
smaller, less, lower
1
1
1
(3)
-23-
4335 IGCSE Chemistry Summer 2008
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
4 (d)(i)
add ice (t o t he beaker or
wat er)
/ cool t he wat er in a
f r idge
use wat er f rom
f ridge
put t ube in ice
add ice t o t ube
add ice t o mixt ure
add ice t o salt
add ice t o solut ion
do experiment in
f r idge
do experiment in
cold room
(1)
Quest ion
Number
Correct Answer Accept able Answers Rej ect Mark
4 (d)(ii)
wat er boils at 100
(° C)
/ (120 ° C is) above
boil ing point of
wat er
Any answer wit h same
meaning, eg
boil ing point of wat er is 100
° C
t his t emperat ure is higher
t han t he boil ing point of
wat er
Accept boil ing t emperat ure,
bp and bpt in place of boil ing
point
Any ot her
answers
(1)
(Total 14 marks)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
5 (a)
Q / chlorine / Cl2
S / ammonia / NH3
T / hydrogen / H2
Award 1 mark each for any t wo
q
s
t
Cl
H
(2)
Quest ion
Number
Correct Answer Accept able
Answers
Rej ect Mark
5 (b)
P / carbon dioxide / CO2
R / sulphur dioxide / SO2
p
r
Any ot her
answers
1
1
(2)
(Total 4 marks)
PAPER TOTAL 50 MARKS
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