Mark Scheme (Results) November 2009

Transcription

1 Scheme (Results) November 2009 IGCSE IGCSE Science (Double Award) (4437) Paper 5H Edexcel Limited. Registered in England and Wales No Registered Office: One90 High Holborn, London WCV 7BH 4335_F Nov 2009 i

2 Edexcel is one of the leading examining and awarding bodies in the UK and throughout the world. We provide a wide range of qualifications including academic, vocational, occupational and specific programmes for employers. Through a network of UK and overseas offices, Edexcel s centres receive the support they need to help them deliver their education and training programmes to learners. For further information, please call our GCE line on , our GCSE team on , or visit our website at If you have any subject specific questions about the content of this Scheme that require the help of a subject specialist, you may find our Ask The Expert service helpful. Ask The Expert can be accessed online at the following link: Alternately, you can speak directly to a subject specialist at Edexcel on our dedicated Science telephone line: (If you are calling from outside the UK please dial and state that you would like to speak to the Science subject specialist). November 2009 Publications Code UG02242 All the material in this publication is copyright Edexcel Ltd _5H Nov 2009 ii

3 S E C T I O N A Question a M (electron) /836 / negligible Accept value in range /2000 to /800 and to Ignore zero M2 (neutron) 0 M3 (proton) M4 (proton) + b i M (number of) protons and neutrons M2 35 ii M 8 c i M 5 ii M isotopes TOTAL 9

4 Question 2 a i M different boiling points / boiling point of propanone lower than that of water ii M heat / boil M2 propanone boils/collects (first) M3 stop collecting liquid above 56 C Accept wording that indicates that water collected separately or not at all b M cross in column box 4 M2 cross in column 2 box 2 TOTAL 6 Question 3 a M (bromine) liquid M2 grey / black b i M any indication of chlorine in left hand tube ii M hydrogen / H 2 iii M brine / sodium chloride solution / NaCl(aq) Accept concentrated/saturated NaCl c M M2 chlorine + sodium bromide bromine + sodium chloride Ignore sea water M reagents M2 products 2 TOTAL _5H Nov

5 Question 4 a M double bond / C=C / not all bonds are single b M contains bromine / another element/atom does not contain only carbon and hydrogen c M B and E d M A and B / A and E / C and F e M alkane(s) M2 C n H 2n+2 Accept other symbols such as x f M yellow / orange / brown M2 colourless / decolorised Ignore clear If only colourless stated, assume it is final colour TOTAL 8 SECTION A TOTAL: 30 MARKS 4437_5H Nov

6 S E C T I O N B Question 5 a i M red Reject orange-red and brick red ii M Li + b M yellow M2 OH c i M melts / becomes a ball M2 moves (on surface) M2 Accept other M3 fizzes / bubbles / effervescence words indicating movement such as darts / whizzes / skids / skates / shoots M4 disappears / dissolves / becomes smaller M5 white trail Reject white precipitate Any two for each Ignore flames/fires ii M M all formulae M2 2Na + 2H 2 O 2NaOH + H 2 correct M2 balancing d i M flame / explosion Accept any more extreme observation from ci, e.g. moves more quickly, faster bubbling, but not just reacts faster/more violently ii M 0-4 / value within this range Reject range outside this, e.g. 9-2 TOTAL _5H Nov

7 Question 6 a i M ammonia M2 hydrogen chloride ii M reversible iii M endothermic b M white solid M2 colourless gas c M forward and reverse reactions still occur M2 at equal rates Accept concentrations of reactants and products equal d M increased M2 increased M3 decreased e M rate increased M2 particles closer together M3 particles collide more often TOTAL _5H Nov

8 Question 7 a M (J) coke / coal Ignore carbon / iron ore / iron oxide M2 (K) limestone Ignore chalk / marble / calcium carbonate Reject lime M3 (L) air Ignore oxygen b i M produces heat/energy / exothermic / raises the temperature ii M reducing agent / removes oxygen from Do not penalise iron oxide / converts iron oxide to iron reference to correct name or formula of any oxide of iron, e.g. iron(ii) oxide, Fe 3 O 4 iii M M reactants CaO + SiO 2 CaSiO 3 M2 M2 products Max if unbalanced c M calcium silicate / slag M2 less dense / lighter d M strong / hard / durable / malleable / ductile M2 catalyst / speeds up the reaction e i M (hydrated) iron (III) oxide Not any other oxide, ii M zinc more reactive (than iron) / higher in reactivity series / better reducing agent / better at losing electrons / transfers electron(s) to iron M2 reacts/corrodes/oxidises instead of/before iron and not just iron oxide Ignore very reactive Ignore rusts TOTAL _5H Nov

9 Question 8 a M % of oxygen =.2 M2 Cu O =.4 = 0.7 M3 Cu 2 O b i M blue ii M solid dissolves / solution forms M2 goes darker/deeper blue iii M complex c i M add sodium hydroxide / NaOH (solution) M2 warm / heat M3 test gas with red litmus paper M4 goes blue ii M add barium chloride (solution) M2 (dilute) hydrochloric acid M3 white precipitate TOTAL _5H Nov

10 Question 9 a M colourless If only one colour given, M2 pink / red assume it is the final colour If both colours correct but wrong way round, award mark b i M 85 Ignore units ii M M2.7 (g) Penalise incorrect units d M heat/boil/evaporate the solution M2 to crystallisation/saturation point / to If clear statement that remove some water all the water is M3 cool and filter / leave solution to evaporated by heating, evaporate/dry then M2 and M3 cannot be awarded OR M leave in warm place/on window ledge M2 for stated time M3 to allow water to evaporate / filter TOTAL 8 SECTION B TOTAL: 60 MARKS PAPER TOTAL: 90 MARKS 4437_5H Nov

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