0620 CHEMISTRY
0620/11 Paper 11 (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 2010 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
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education
MARK SCHEME for the May/June 2010 question paper for the guidance of teachers
0620 CHEMISTRY
0620/12 Paper 12 (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 2010 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
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education
MARK SCHEME for the May/June 2010 question paper for the guidance of teachers
0620 CHEMISTRY
0620/13 Paper 13 (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 2010 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
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education
MARK SCHEME for the May/June 2010 question paper for the guidance of teachers
0620 CHEMISTRY
0620/21 Paper 21 (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 2010 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
motion: random / fast / irregular OWTTE [1]
(b) two paired electrons and two atoms indicated [1]
(c) (i) atom of (same) element with different number of neutrons / atoms with
same number of protons and different number of neutrons [1]
(ii) number of electrons 1 and 1 [1]
number of neutrons for H-1 = 0 [1]
number of neutrons for H-3 = 2 [1]
number of protons 1 for both [1]
(d) exothermic [1]
(e) (i) magnesium>zinc>iron>cobalt [2]
one pair reversed = 1 mark
(ii) calcium chloride; carbon dioxide; water; [3]
3 (a) (i) reversible / decomposition [1]
(ii) hydrated; water; [2]
(b) (i) any two e.g. conducts electricity / conducts heat / sonorous / shiny etc [2]
(ii) forms coloured compounds / forms ions or compounds with variable oxidation state / good catalyst / high melting point OR high boiling point / forms complex ions [2]
(c) reacts with acids / forms a salt and water with acids [1]
Page 3 Mark Scheme: Teachers’ version Syllabus Paper
(d) add (nitric acid and) silver nitrate / lead nitrate [1]
yellow ppt [1]
(e) (i) I2 [1]
(ii) brown / yellowish brown [1]
not: grey / black
(iii) bromine is more reactive than iodine OWTTE [1]
(f) 95 [1]
5 (a) nitrogen; phosphorus; potassium; [3]
(b) any two of:
plants take up nitrogen / phosphorus / potassium;
nitrogen / phosphorus / potassium needs to be replaced;
to enable better plant growth / greater yield / otherwise plants won’t grow as well (idea of
increase / more needed) [2]
(c) (i) dissolves or idea of dissolving [1]
(ii) titration of acid with alkali / last box ticked [1]
(d) ammonia [1]
(e) (i) calcium oxide / lime [1]
allow: calcium hydroxide / limestone / calcium carbonate
(ii) plants grow best at certain pH’s / link between pH and plant growth;
farmers want to get best yield; OWTTE [2]
(f) (i) 4 [1]
(ii) 15 [1]
Page 4 Mark Scheme: Teachers’ version Syllabus Paper
(iii) each arrow or number in the correct position (1 mark each) [4]
(c) ZnS [1]
7 (a) boiling point / first box down ticked [1]
(b) fuel oil: fuel for home heating;
kerosene: jet fuel;
lubricating fraction: waxes and polishes;
naphtha: making chemicals; [4]
(c) (i) high temperature; catalyst; [2]
(ii) C12H26 [1]
(iii) correct structure showing all atoms and bonds [1]
(d) poly(ethene) allow: polythene [1]
(e) (i) steam [1]
(ii) substance which speeds up rate / speed of reaction [1]
8 (a) 1st, 3rd and 4th boxes down ticked (aqueous sodium chloride, copper and graphite) [3]
(b) insulator [1]
(c) (i) anode [1]
(ii) negative electrode: zinc [1]
positive electrode: chlorine [1]
(iii) graphite [1]
allow: carbon
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education
MARK SCHEME for the May/June 2010 question paper for the guidance of teachers
0620 CHEMISTRY
0620/22 Paper 22 (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 2010 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
3 (a) coolant / making ethanol / any other names large scale relevant reaction
e.g. making sulfuric acid [1]
(b) blue / anhydrous cobalt chloride (paper); turns pink; [2]
OR white / anhydrous copper sulfate; turns blue;
(c) (i) lighted splint;
pops / explodes; [2]
(ii) pH 12 [1]
(d) (i) 3 (CO2); 4(H2O); [2]
(ii) combustion [1]
(iii) 36 (mg) [1]
Page 3 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2010 0620 22
© UCLES 2010 4 (a) Any 2 of:
diffusion / ink particles move /
water particles or molecules move /
movement of particles is random / [2]
(b) two or more substances (together) that can be separated by physical means [1]
(c) (i) ethanol [1]
allow: carboxylic acids
(ii) oxidation state / third box down ticked [1]
(iii) idea of small molecules / monomers joining / repeating units;
long chains / large molecules formed; [2]
(d) (i) ring around COOH group [1]
(ii) removal of oxygen / decrease in oxidation number / addition of electrons [1]
5 (a) filtration / centrifugation [1]
allow: decanting
(b) C [1]
(c) (i) solvent shown in bottom of beaker; [1]
spot on the base line vertically below the spots shown; [1]
chromatography paper labelled anywhere; [1]
(ii) 4 [1]
(d) (i) A [1]
(ii) bromine water;
decolourises / goes colourless; [2]
allow: potassium manganate (VII); decolourises;
(iii) substance containing carbon and hydrogen only [1]
(iv) ethanoic acid [1]
(v) alcohols / alkanols [1]
Page 4 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2010 0620 22
© UCLES 2010
6 (a) conduct heat / conduct electricity / shiny / malleable / ductile max [2] [2]
(b) 4 [1]
BMF molecule and diamond a giant covalent structure / [1]
BMF has pentagonal (and hexagonal) structure diamond has bent hexagonal or tetrahedral structure /
BMF each carbon joined to 3 others, diamond each carbon joined to four others / (ii) two of:
graphite has (flat) hexagonal rings, diamond has bent hexagonal rings or tetrahedral/ graphite has 3 bonds to each carbon, diamond has 4 /
graphite is layered diamond is not /
graphite has two types of bonding / forces or weak and strong bonds whereas
diamond has only one type of bond / covalent bonds only [2]
(b) covalent [1]
(c) layers can slide over each other / forces weak between layers [1]
(d) cutting / drilling allow: jewellery [1]
(e) any 2 of:
carbon dioxide is a greenhouse gas / absorbs infrared radiation /
increases global warming /
lead to climate change / [2]
(f) any two of:
sulfur reacts with oxygen (when coal burnt) / forms sulfur dioxide /
sulfur dioxide reacts with oxygen (to form sulfur trioxide) /
sulfur dioxide or trioxide dissolve in rain (to form acid) / [2]
Page 5 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2010 0620 22
© UCLES 2010
(g) (i) waste gases from digestion in animals / second box down ticked [1]
(ii) correct dot and cross diagram for methane [1]
(iii) ethane / propane / butane etc [1]
8 (a) calcium oxide [1]
(b) thermal decomposition [1]
(c) carbon dioxide has been removed from the limestone / it comes from the limestone [1]
(d) neutralising acid soils / treating acidic lakes / flue gas desulfurisation etc [1]
(e) temperature of Bunsen / distance of Bunsen from the tube / amount or mass of
carbonate used [1]
(f) (i) calcium [1]
(ii) 25 cm3 [1]
(iii) calcium faster than strontium which is faster than barium / idea of trend down the group;
correct trend i.e. less rapid reaction the further down the group; ORA [2]
(g) add acid to carbonate;
bubble gas or carbon dioxide (evolved) through limewater / test gas or carbon dioxide with limewater;
limewater goes milky or cloudy; [3]
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education
MARK SCHEME for the May/June 2010 question paper for the guidance of teachers
0620 CHEMISTRY
0620/31 Paper 31 (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 2010 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 accept correct symbols
2 (i) chloromethane [1]
cond biggest molecular mass / biggest mass of one mole / its molecules
move slowest / heaviest molecule / highest density [1]
accept atomic mass if correct numerical value given ignore it is the heaviest (gas) / biggest molecule
accept particles or molecules not atoms
(ii) carbon dioxide / calcium carbonate [1]
not methane
not combustion or exhaust, negates mark 2
(v) 2O3 3O2 [2]
Page 3 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2010 0620 31
© UCLES 2010
(d) temperature / heat [1]
increase temperature – reaction faster particles have more energy / particles move faster / particles collide more frequently / more particles have enough energy to react not more excited
accept arguments for a decrease in temperature [1]
powdered
greater surface area
greater collision rate / more particles exposed (to acid)
any two [2]
not concentration / light / catalyst / pressure
4 (a) (i) ethanol [1]
CH3-CH2-OH [1]
propanoic acid [1]
CH3-CH2-COOH [1]
independent marking, no ecf accept C2H5
not – HO
(ii) type of compound – salt / sodium carboxylate / alkanoate [1]
not soap / sodium stearate etc
use – soap / cleaning / detergent [1]
(iii) terylene / PET / Dacron / diolen / mylar / crimplene [1]
(b) (i) polyamide / amide / peptide / polypeptide [1]
(ii) correct amide linkage NHCO then CONH [1]
cond to mark 1, 2 monomers (different shading in box) [1]
cond continuation (to ONE correct linkage) [1]
OR nylon 6
only one linkage – NHCO [1]
cond only one monomer [1]
cond continuation (to correct linkage) [1]
(iii) use locating agent [1]
measure distance travelled by sample / travelled by solvent front [1]
cond this is Rf = 0.5 [1]
for mark 3, either mark 1 or mark 2 must be awarded accept run a chromatogram of glycine [1]
compare with sample same position [1] max [2]