0620 CHEMISTRY
0620/11 Paper 1 (Multiple Choice), maximum raw mark 40
Mark schemes must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes.
CIE is publishing the mark schemes for the May/June 2009 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
First variant Mark Scheme
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education
MARK SCHEME for the May/June 2009 question paper for the guidance of teachers
0620 CHEMISTRY
0620/12 Paper 1 (Multiple Choice), maximum raw mark 40
Mark schemes must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes.
CIE is publishing the mark schemes for the May/June 2009 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
Second variant Mark Scheme
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education
MARK SCHEME for the May/June 2009 question paper for the guidance of teachers
0620 CHEMISTRY
0620/02 Paper 2 (Core Theory), maximum raw mark 80
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers.
Mark schemes must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes.
CIE is publishing the mark schemes for the May/June 2009 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.XtremePapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
ALLOW: hydroxide / OH–
NOT: sodium
(v) methane; [1]
(b) (i) oxygen is removed (from the iron oxide); [1]
ALLOW: carbon takes the oxygen from the iron oxide
ALLOW: oxygen goes to the carbon / the oxygen combines with the carbon ALLOW: oxidation number of iron decreases / electrons added to iron NOT: the iron oxide loses electrons
(ii) haematite;
(b) bubbles produced steadily / moderately / slowly /
bubbles produced faster than iron and slower than magnesium /
fewer bubbles than magnesium and more than iron; [1]
ALLOW: many bubbles produced but less than magnesium NOT: bubbles produced rapidly / less rapidly
NOT: less bubbles than magnesium / more bubbles than iron NOT: reaction / it’s faster than iron and slower than magnesium
(c) (i) magnesium floats on top of the magnesium chloride ORA /
magnesium is above the magnesium chloride ORA; [1]
ALLOW: magnesium is on top of the magnesium chloride ORA
(ii) (magnesium) too reactive / above carbon in reactivity series / more reactive than
carbon; [1]
ALLOW: magnesium is a reactive metal / magnesium is reactive ALLOW: too high a temperature needed for the extraction NOT: magnesium oxide / magnesium will not react with carbon
Page 3 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 02
© UCLES 2009
(iii) to prevent magnesium reacting with the air / oxygen / nitrogen; [1]
ALLOW: to stop magnesium oxidising NOT: because it is reactive
NOT: to stop it reacting
NOT: because inert gases are unreactive
(iv) nitrogen / helium / neon / argon / krypton / xenon / radon; [1]
(d) (i) structure of ethene showing all atoms and all bonds; [1]
ALLOW: correct electronic structure
(ii) two of: [2]
(1 mark each)
• carbon monoxide + poisonous / toxic;
ALLOW: carbon monoxide combines with haemoglobin / red blood cells ALLOW: carbon monoxide suffocates
NOT: carbon monoxide harmful / dangerous
• hydrogen + flammable / explosive;
NOT: hydrogen dangerous
• hydrogen sulfide + poisonous / toxic;
ALLOW: harmful
NOT: dangerous / affects breathing
• ethene + flammable;
• methane + flammable;
ALLOW: explosive
(e) (i) carbon monoxide + water / steam → carbon dioxide + hydrogen; [1]
ALLOW: arrow for equilibrium sign
NOT: carbon oxide instead of carbon monoxide NOT: mixture of words and symbols
(ii) equilibrium / reversible reaction / the reaction can go both ways / the reaction can
go backwards or forwards; [1]
ALLOW: the reaction can also go backwards NOT: the reaction goes backwards
(iii) add sodium hydroxide (solution) / (aqueous) ammonia; [1]
(red-)brown / rusty red precipitate (both points); [1]
ALLOW: solid for precipitate
ALLOW: yellow-brown precipitate / orange precipitate
IGNORE: references to excess ammonia / sodium hydroxide NOT: red precipitate
[Total: 13]
Page 4 Mark Scheme: Teachers’ version Syllabus Paper
• lubricating oil / lubricating fraction; (NOT: lubricant)
• bitumen; (ALLOW: residue)
IGNORE: kerosene / paraffin / gasoline / petrol / diesel IGNORE: methane / named chemical compounds IGNORE: gas alone
(c) oil stoves / aircraft fuel / for jet engines / for car engines; [1]
ALLOW: for making more petrol
ALLOW: for cooking / for heating / for lighting / for fuel
(d) A and D; (both needed) [1]
(e) ethane;
unreactive;
oxygen;
water; [4]
(f) saturated: has only single bonds / contains the maximum amount of hydrogen atoms
(that can be combined with carbon atoms); [1]
ALLOW: does not have double bonds ALLOW: consists of single bonds NOT: has single bonds
hydrocarbon: (compound / substance) containing hydrogen and carbon only / it has
carbon and hydrogen only; [1]
REJECT: it has carbon and hydrogen molecules only / ideas of mixtures of carbon and hydrogen
[Total: 11]
Page 5 Mark Scheme: Teachers’ version Syllabus Paper NOT: goes blue then bleaches NOT: goes purple
ALLOW: to make (crop) plants grow better ALLOW: to make plants grow more / faster ALLOW: to improve crop yield
IGNORE: to replace minerals lost from the soil / to replace nutrients
(ii) more nitrogen / greater percentage of nitrogen; [1]
NOT: more nitrate
(iii) 80; [1]
(e) oxygen / O2; [1]
NOT: O
(f) acid rain / effect of acid rain e.g. trees or plants die / pond animals die / fish die /
erosion of buildings / corrosion of bridges; [1]
ALLOW: smog / damages buildings NOT: destroys buildings
NOT: breathing difficulties / lung damage / irritation to throat / poisonous / harmful
[Total: 10]
Page 6 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 02
© UCLES 2009
5 (a) carbon dioxide released / gas is released / gas is formed; [1]
NOT: we get carbon dioxide, calcium chloride and water
(b) (i) 615 s; [1]
ALLOW: in numbers in range 600–630 s
(ii) X on or near the line at beginning of experiment; [1]
ALLOW: on or near line up to 50 s
(iii) shallower curve at initial rate; [1]
starts levelling off at 100.2 g; [1]
ALLOW: (beginning to) level off between 100.15 and 100.25 g
(c) (i) increases / goes faster; [1]
NOT: takes less time / becomes fast / reaction increases
(ii) increases / goes faster; [1]
NOT: takes less time / becomes fast / reaction increases
(d) combustion;
ALLOW: changes rate of reaction NOT: decreases the rate
IGNORE: references to biological substances
[Total: 12]
Page 7 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 02
© UCLES 2009
6 (a) Br2; [1]
(b) particles random AND roughly similar size to the one shown; [1]
particles very close together or touching; [1]
(c) Any three of: [3]
• bromine evaporates / liquid evaporates; (NOT: it evaporates)
• more energetic particles from liquid to vapour;
• diffusion;
• random movement of molecules / particles move everywhere / both air and bromine particles are moving;
• (bromine and air) particles get mixed up / collision of bromine and air particles;
ALLOW: molecules in place of particles NOT: atoms in place of particles
(d) (light) green; [1]
IGNORE: yellow to
reddish-brown / brown / orange / yellow-brown; [1]
NOT: yellow / red
(e) bromine higher in reactivity series than iodine / bromine more reactive than iodine; [1]
NOT: bromide more reactive than iodide NOT: magnesium bromide more reactive NOT: bromine stronger than iodine
(f) (i) NaBr; [1]
ALLOW: Na+Br–
NOT: multiples e.g. 2NaBr
(ii) zinc bromide; [1]
ALLOW: the ions are free (from each other) NOT: ions delocalised / charged particles moved REJECT: electrons and ions move
[Total: 14]
Page 8 Mark Scheme: Teachers’ version Syllabus Paper
chlorine electrons all correct and no other electrons on hydrogen; [1]
ALLOW: use of circle / dot for chlorine and cross for hydrogen IGNORE: inner electrons
(c) pH1; [1]
(d) hydrogen; [1]
NOT: H2
(e) Any two of: [2]
• evaporate off some of the water / heat solution to crystallisation point;
ALLOW: concentrate the solution
NOT: boil off the water / implication that all the water is removed NOT: heat without further qualification
• leave to crystallise / leave in the warm / leave in the air / leave on a window sill / leave at room temperature;
NOT: let it cool / leave it to cool
• dry crystals with filter paper;
NOT: heat / warm to dry / put in an oven
(f) (i) chlorine / Cl2; [1]
NOT: Cl
(ii) zinc / Zn; [1]
[Total: 10]
Location Entry Codes
As part of CIE’s continual commitment to maintaining best practice in assessment, CIE has begun to use different variants of some question papers for our most popular assessments with extremely large and widespread candidature, The question papers are closely related and the relationships between them have been thoroughly established using our assessment expertise. All versions of the paper give assessment of equal standard.
The content assessed by the examination papers and the type of questions are unchanged.
This change means that for this component there are now two variant Question Papers, Mark Schemes and Principal Examiner’s Reports where previously there was only one. For any individual country, it is intended that only one variant is used. This document contains both variants which will give all Centres access to even more past examination material than is usually the case.
The diagram shows the relationship between the Question Papers, Mark Schemes and Principal Examiner’s Reports.
Question Paper Mark Scheme Principal Examiner’s Report
Introduction Introduction Introduction
First variant Question Paper First variant Mark Scheme First variant Principal Examiner’s Report Second variant Question Paper Second variant Mark Scheme Second variant Principal
Examiner’s Report
Who can I contact for further information on these changes?
Please direct any questions about this to CIE’s Customer Services team at: [email protected]
www.XtremePapers.com
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education
MARK SCHEME for the May/June 2009 question paper for the guidance of teachers
0620 CHEMISTRY
0620/31 Paper 3 (Extended Theory), maximum raw mark 80
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers.
Mark schemes must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes.
CIE is publishing the mark schemes for the May/June 2009 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
First variant Mark Scheme
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 31
© UCLES 2009
1 (a) (i) basic set up – container and chromatography paper [1]
sample clearly above level of solvent [1]
(original mark must be shown and not just the line)
indication that more than one “spot” either on diagram or as comment [1]
Allow MAX [2] for round filter paper with green spot at centre two or more rings
(ii) run chromatogram of pure chlorophyll can be implied [1]
same position of green spot or same Rf [1]
NOT just a green spot
(b) catalyst
photosynthesis or chloroplasts photochemical reaction or needs light
carbon dioxide + water form
glucose or starch or oxygen NOT sugar
Any THREE correct points ignore incorrect answers [3]
[Total: 8]
2 molten potassium iodide NOT aqueous [1]
hydrogen [1]
oxygen [1]
water used up or solution becomes more concentrated or sodium chloride remains
NOT no change [1]
If products are given as hydrogen, chlorine and sodium hydroxide then 2/3
copper [1]
oxygen (and water) [1]
sulfuric acid accept hydrogen sulfate [1]
aqueous or dilute or concentrated potassium bromide [1]
accept correct formulae
Page 3 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 31
© UCLES 2009
(b) (i) CF2or CaI2 [1]
COND next two marks conditional on correct formula
C2+ and F– or Ca2+ and I– [1]
7× and 1o round F/I [1]
NOTE covalent = 0
Ignore electrons around Ca
accept arrow notation arrow from electron on calcium atom to iodine (ii) high melting point or boiling point
NOT crystalline solid NOT does not conduct as a solid
[Total: 10]
Both species must be correct for first mark. Second mark is for correct balancing.
(ii) Mole ratio Ca2+: F– is 1:2 [1]
Answer must mention moles
accept argument based on charges or number of ions accept 2 moles of NaF react with 1 mole of CaCl2
NOT just “2” in equation
If fluorine must specify atoms or ions
(iii) to remove traces of solutions or to remove soluble impurities or to remove a named salt sodium chloride
or sodium fluoride or calcium chloride [1]
To remove impurities is not enough
(iv) to dry (precipitate) or to remove water or to evaporate water [1]
NOT to evaporate some of water NOT to crystallise salt First variant Mark Scheme
Page 4 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 31
© UCLES 2009
(b) T3(PO4)2 allow correct example [1]
explain why 8 cm3 react fully [1]
comment about mole ratio [1]
[Total: 8]
6 (a) (i) air (liquid) [1]
petroleum or crude oil or alkanes or methane or water or steam or steam reforming or suitable aqueous solution e.g. brine or sea water [1]
NOTE: cannot crack methane
(ii) iron [1]
(iii) (as a) fertiliser or to make fertilisers or to make nitric acid [1]
(b) (i) concentrations/macroscopic properties do not change [1]
accept amounts stay the same NOT no change
rate of forward and back reactions equal [1]
(ii) it decreases with increase temperature [1]
or it increases with decrease temperature
(c) (i) shows an increase either a line or curve [1]
(any decrease = 0)
(ii) increase pressure favours the side with lower volume or molecules or moles [1]
that is RHS or products side [1]
ignore any mention of rates
[Total: 10]
7 (a) (total endothermic change = 436 + 242 = +)678 kJ [1]
(total exothermic change = 2 × 431 = –)862 kJ [1]
accept correct sign/supplied/absorbed for endo etc.
accept correct sign/evolved/produced for exo etc.
change for reaction = –184 kJ [1]
not necessary to calculate –184, just show that exo change > than endo ecf allowed provided negative
–184 kJ scores all 3 marks
(b) (i) because it accepts a proton [2]
accepts hydrogen ion or H+ ONLY [1]
proton and H+ [2]
(ii) hydrogen chloride is a strong acid [1]
hydrogen fluoride is a weak acid [1]
weaker or stronger correctly applied for [2]
First variant Mark Scheme
Page 5 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 31
© UCLES 2009
(iii) hydrogen chloride (aqueous) would have lower pH [1]
OR hydrogen fluoride (aqueous) would have higher pH If values suggested, not over 7
[Total: 8]
8 (a) biodegradable or breaks down naturally
made from a renewable source or does not use up petroleum
reduce visual pollution or reduces need for landfill sites or less danger to wildlife
any TWO [2]
ignore mention of toxic gases
(b) (i) ester [1]
accept polyester or fat or lipid or vegetable oil or carboxylic acid
(ii) acid or carboxylic acid or alkanoic acid [1]
alcohol or hydroxyl or alkanol [1]
NOT formulae NOT hydroxide
(iii) condensation [1]
COND because water is formed in reaction
or monomer does not have C=C bond [1]
(c) (i) lactic acid → acrylic acid + water [1]
(ii) add bromine (water) or bromine in an organic solvent [1]
remains brown/orange/yellow [1]
goes colourless NOT clear [1]
If mark 1 near miss e.g. bromide allow marks 2 and 3
Colour of reagent must be shown somewhere for [3] otherwise max [2]
OR acidified potassium manganate(VII) purple/pink to colourless
OR alkaline potassium manganate(VII) purple/pink to green
or purple/pink to brown precipitate First variant Mark Scheme
Page 6 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 31
© UCLES 2009
(iii) reagent [1]
observable result [1]
suitable named metal (NOT sodium, lead, any metal below magnesium etc.) if un-named metal [0] result can score [1]
hydrogen evolved or bubbles/effervescence/fizzing insoluble metal oxide
colour change or dissolves any carbonate or bicarbonate
gas/carbon dioxide/bubbles/effervescence/fizzing sodium hydroxide or alkali
temperature increase or accept indicator to show neutralisation unspecified base scores [1] only
NOT alcohol
[Total: 13]
9 (a) 72/24 = 3 and 28/14 = 2 [1]
Mg3N2 [1]
accept just formula for [2] even with incorrect or no working NOT ecf arguments based on masses can be used
(ii) 0.07 [1]
NOT ecf
[Total: 8]
First variant Mark Scheme
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education
MARK SCHEME for the May/June 2009 question paper for the guidance of teachers
0620 CHEMISTRY
0620/32 Paper 3 (Extended Theory), maximum raw mark 80
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers.
Mark schemes must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes.
CIE is publishing the mark schemes for the May/June 2009 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
Second variant Mark Scheme
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 32
© UCLES 2009
1 (a) (i) basic set up – container and chromatography paper [1]
sample clearly above level of solvent [1]
(original mark must be shown and not just the line)
indication that more than one “spot” either on diagram or as comment [1]
Allow MAX [2] for round filter paper with green spot at centre two or more rings
(ii) run chromatogram of pure chlorophyll can be implied [1]
same position of green spot or same Rf [1]
NOT just a green spot
(b) catalyst
photosynthesis or chloroplasts photochemical reaction or needs light
carbon dioxide + water form
glucose or starch or oxygen NOT sugar
Any THREE correct points ignore incorrect answers [3]
[Total: 8]
2 molten lithium chloride NOT aqueous [1]
hydrogen [1]
oxygen [1]
water used up or solution becomes more concentrated or sodium chloride remains
NOT no change [1]
If products are given as hydrogen, chlorine and sodium hydroxide then 2/3
copper [1]
oxygen (and water) [1]
sulfuric acid accept hydrogen sulfate [1]
aqueous or dilute or concentrated potassium bromide [1]
accept correct formulae
Page 3 Mark Scheme: Teachers’ version Syllabus Paper
Ignore electrons around Ca
accept arrow notation arrow from electron on calcium atom to oxygen (ii) high melting point or boiling point
conducts when molten or in solution soluble in water
brittle
basic(oxide) or basic property hard
Any TWO [2]
NOT crystalline solid NOT does not conduct as a solid
[Total: 10]
Both species must be correct for first mark. Second mark is for correct balancing.
(ii) Mole ratio Fe3+: F– is 1:3 [1]
Answer must mention moles
accept argument based on charges or number of ions accept 1mole of FeF3 reacts with 3 moles of NaF
NOT just “3” in equation
If fluorine must specify atoms or ions
(iii) to remove traces of solutions or to remove soluble impurities or to remove a named salt sodium chloride
or sodium fluoride or iron(III) chloride [1]
To remove impurities is not enough
(iv) to dry (precipitate) or to remove water or to evaporate water [1]
NOT to evaporate some of water Second variant Mark Scheme
Page 4 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 32
© UCLES 2009
(b) T3PO4 allow correct example [1]
explain why 6 cm3 react fully [1]
comment about mole ratio [1]
[Total: 8]
6 (a) (i) air (liquid) [1]
petroleum or crude oil or alkanes or methane or water or steam or steam reforming or suitable aqueous solution e.g. brine or sea water [1]
NOTE: cannot crack methane
(ii) iron [1]
(iii) (as a) fertiliser or to make fertilisers or to make nitric acid [1]
(b) (i) concentrations/macroscopic properties do not change [1]
accept amounts stay the same NOT no change
rate of forward and back reactions equal [1]
(ii) it increases with increase pressure [1]
or it decreases with decrease pressure
(c) (i) shows a decrease either a line or curve [1]
(any increase = 0)
(ii) increase temperature favours the endothermic change [1]
that is LHS or reactants side or so less ammonia at equilibrium [1]
accept corresponding exothermic argument
[Total: 10]
7 (a) (total endothermic change = 436 + 158 = +)594 kJ [1]
(total exothermic change = 2 × 562 = –)1124 kJ [1]
accept correct sign/supplied/absorbed for endo etc.
accept correct sign/evolved/produced for exo etc.
change for reaction = –530 kJ [1]
not necessary to calculate –530, just show that exo change > than endo ecf allowed provided negative
–530 kJ scores all 3 marks
(b) (i) because it accepts a proton [2]
accepts hydrogen ion or H+ ONLY [1]
proton and H+ [2]
(ii) hydrogen chloride is a strong acid [1]
hydrogen fluoride is a weak acid [1]
weaker or stronger correctly applied for [2]
Second variant Mark Scheme
Page 5 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 32
© UCLES 2009
(iii) hydrogen chloride (aqueous) would have lower pH [1]
OR hydrogen fluoride (aqueous) would have higher pH If values suggested, not over 7
[Total: 8]
8 (a) biodegradable or breaks down naturally
made from a renewable source or does not use up petroleum
reduce visual pollution or reduces need for landfill sites or less danger to wildlife
any TWO [2]
ignore mention of toxic gases
(b) (i) ester [1]
accept polyester or fat or lipid or vegetable oil or carboxylic acid
(ii) acid or carboxylic acid or alkanoic acid [1]
alcohol or hydroxyl or alkanol [1]
NOT formulae NOT hydroxide
(iii) condensation [1]
COND because water is formed in reaction
or monomer does not have C=C bond [1]
(c) (i) lactic acid → acrylic acid + water [1]
(ii) add bromine (water) or bromine in an organic solvent [1]
remains brown/orange/yellow [1]
goes colourless NOT clear [1]
If mark 1 near miss e.g. bromide allow marks 2 and 3
Colour of reagent must be shown somewhere for [3] otherwise max [2]
OR acidified potassium manganate(VII) purple/pink to colourless
OR alkaline potassium manganate(VII) purple/pink to green
or purple/pink to brown precipitate Second variant Mark Scheme
Page 6 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2009 0620 32
© UCLES 2009
(iii) reagent [1]
observable result [1]
suitable named metal (NOT sodium, lead etc.) gas/hydrogen/bubbles/effervescence/fizzing
if un-named metal [0] result can score [1]
insoluble metal oxide colour change or dissolves any carbonate
gas/carbon dioxide/bubbles/effervescence/fizzing accept bicarbonate
sodium hydroxide or alkali
(temperature increase or accept indicator to show neutralisation) unspecified base scores [1] only
NOT alcohol
[Total: 13]
9 (a) 72/24 = 3 and 28/14 = 2 [1]
Mg3N2 [1]
accept just formula for [2] even with incorrect or no working NOT ecf arguments based on masses can be used
(ii) 0.08 [1]
NOT ecf
[Total: 8]
Second variant Mark Scheme
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education
MARK SCHEME for the May/June 2009 question paper for the guidance of teachers
0620 CHEMISTRY
0620/05 Paper 5 (Practical Test), maximum raw mark 40
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began,
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began,