MARK SCHEME for the February/March 2016 series 0620 CHEMISTRY

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1 CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International General Certificate of Secondary Education MARK SCHEME f the February/March 06 series 060 CHEMISTRY 060/4 Paper 4 (Extended They), 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 befe marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Rept f Teachers. Cambridge will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes f the February/March 06 series f most Cambridge IGCSE and Cambridge International A and AS Level components. IGCSE is the registered trademark of Cambridge International Examinations.

2 Page Mark Scheme Syllabus Paper Cambridge IGCSE February/March Abbreviations used in the Mark Scheme ; separates marking points / separates alternatives within a marking point () the wd phrase in brackets is not required but sets the context A accept (a less than ideal answer which should be marked crect) I igne (mark as if this material were not present) R reject ecf credit a crect statement that follows a previous wrong response a reverse argument owtte wds to that effect (accept other ways of expressing the same idea) Cambridge International Examinations 06

3 Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE February/March (a) B = 7; C = 8; D =,8; / ; (b) (c) Substance that cannot be broken down into anything simpler / substance that cannot be broken down (by chemical means) / substance containing atoms with the same atomic number proton number; number of protons number of neutrons number of electrons M column one; M column two; M3 column three; 4 3 (a) ; (b) conducts electricity heat / malleable / ductile / sonous / shiny; (c) any two from: (low) melting point / (low) boiling point; hardness / softness / rubidium can be cut easily; strength; (low) density; Cambridge International Examinations 06

4 Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE February/March (d)(i) any two from: bubbles / effervescence / fizzing; flame / sparks / ignites; movement; dissolves / fms a solution / disappears / gets smaller; floats; rubidium melts / rubidium fms a ball; explosion; (d)(ii) yellow; (d)(iii) Rb + H O RbOH + H fmula of RbOH; whole equation completely crect; (d)(iv) caesium rubidium potassium sodium lithium / Cs Rb K Na Li; (d)(v) goggles / glasses / gloves / safety screen / stand at safe distance / tongs / open space; (e) Rb 3 PO 4 ; 3(a) CO ; 4 simple molecular / simple (covalent); solid; po conduct / non-conduct; 3(b)(i) covalent; Cambridge International Examinations 06

5 Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE February/March (b)(ii) 3(b)(iii) all bonds are (very) strong bonds; bonds need a lot of energy heat to break; (there are) no weak bonds / no (weak) intermolecular fces; weak fces between molecules; weak intermolecular fces weak van der Waals fces; low amount of energy needed to break intermolecular / van der Waals fces; 3(b)(iv) no (moving) ions / no mobile moving electrons / all electrons used in bonding / made of uncharged molecules; 3(c) NaOH + CO Na CO 3 + H O NaOH + CO NaHCO 3 fmula of Na CO 3 / Na HCO 3 ; whole equation crect; 3(d)(i) (complete) combustion / burning; 3(d)(ii) photosynthesis; 3(d)(iii) respiration; Cambridge International Examinations 06

6 Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE February/March (a) M (substance that) speeds up a reaction / increases the rate of a reaction; M any one from: unchanged (chemically at the end) / not used up; lowers activation energy; 4(b)(i) at the start/initially / t = 0; 4(b)(ii) catalyst should be powdered / increase surface area (of catalyst) / decrease particle size (of catalyst); increase temperature / heat / warm; 4(c)(i) 0.00 (mol); 4(c)(ii) 0.00 (mol); 4(c)(iii) 0.04 (dm 3 ); 4(c)(iv) no change / no effect; 4(c)(v) (dm 3 ); 4(d) same mass / amount of / moles /.0 g of catalyst; same temperature; same volume and concentration of hydrogen peroxide / 0 cm 3 of 0. mol / dm 3 of hydrogen peroxide reactant; 3 Cambridge International Examinations 06

7 Page 7 Mark Scheme Syllabus Paper Cambridge IGCSE February/March (a)(i) pressure in range atmospheres / atm; temperature in range C; iron (catalyst); balanced equation: N + 3H NH 3 ; equilibrium / reversible; 5(a)(ii) manufacture of fertilisers / nylon / nitric acid / cleaning agent(allow oven cleaner) / hair dye / urea / refrigeration / explosives; 5(b) H H N N H H 5 M all shared electrons crect (5 bonds); M exactly two non-bonding electrons on each N and no additional non-bonding electrons; 5(c)(i) proton / H + accept; 5(c)(ii) (N H 4 + H O) N H OH ; (N H 4 ) + H O N H OH ; 5(d)(i) acid rain / effect of acid rain / (photochemical) smog / (producing) low level ozone; 5(d)(ii) M nitrogen and oxygen (from the air) react / combine wd equation; M at high temperature / spark / very hot; Cambridge International Examinations 06

8 Page 8 Mark Scheme Syllabus Paper Cambridge IGCSE February/March (a) S ; S ; 6(b) test conductivity; gold conducts / a; malleability / hit with a hammer; gold malleable / only gold produces ringing sound / a; density; gold denser / a; add acid / any named / fmula of acid; gold does not react (igne products with pyrites) / a; heat (both strongly) in air / oxygen; iron pyrite reacts (igne products); melting point; gold lower / a; heat with a me reactive metal than iron; gold does not react / a; 6(c)(i) 4FeS + O Fe O 3 + 8SO all fmulae; balancing; Cambridge International Examinations 06

9 Page 9 Mark Scheme Syllabus Paper Cambridge IGCSE February/March (c)(ii) bleaching (in the manufacture of) wood pulp (f paper straw wool cotton) / (food) preservative killing bacteria in food wine / fumigant / refrigerant / tanning(leather); 7(a)(i) compound containing carbon and hydrogen only; 7(a)(ii) C n H n+ ; C n H n ; 7(b)(i) mol C = / 4.5(45) and mol H = 9.09 / 9.09 and mol O = / 6.7; C H 4 O; 7(b)(ii) M r of C H 4 O = 44; 88 / 44 = therefe C 4 H 8 O ; 7(c) methyl ethanoate; ethyl methanoate; CH 3 COOCH 3 ; HCOOC H 5 ; 7(d) methyl propanoate; 7(e)(i) condensation; 7(e)(ii) water / H O; 7(e)(iii) dicarboxylic acid diacyl chlide; diol; 4 Cambridge International Examinations 06

Cambridge International Examinations Cambridge International General Certificate of Secondary Education. Published

Cambridge International Examinations Cambridge International General Certificate of Secondary Education CHEMISTRY 060/4 Paper 4 Theory (Extended) May/June 06 MARK SCHEME Maximum Mark: 80 Published This