Cambridge IGCSE Science - Combined 0653 — 2011 Oct/Nov Paper 3 · Variant 1

This document consists of 19 printed pages and 1 blank page. IB11 11_0653_31/4RP © UCLES 2011 [Turn over *5908076902* For Examiner's Use 1 2 3 4 5 6 7 8 9 Total UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/31 Paper 3 (Extended) October/November 2011 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs, tables or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. A copy of the Periodic Table is printed on page 20. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. www.XtremePapers.com

2 © UCLES 2011 0653/31/O/N/11 For Examiner's Use 1 The chemical reaction involved in the manufacture of ammonia requires an iron catalyst. Fig.1.1 shows a simplified diagram of the reaction vessel in which ammonia is made. nitrogen gas ammonia hydrogen gas catalyst Fig. 1.1 (a) (i) Explain the meaning of the term catalyst. [2] (ii) Iron is a member of the family of metals which lies between scandium and zinc in the Periodic Table. Name this family of metals. [1] (iii) The iron catalyst is prepared by reacting iron oxide with hydrogen gas. The symbolic equation below for this reaction is not balanced. Complete the balancing of the equation. Fe3O4 + H2 Fe + H2O [2] (iv) Explain, in terms of the loss or gain of electrons, whether iron is oxidised or reduced in the reaction in (iii). [2]

3 © UCLES 2011 0653/31/O/N/11 [Turn over For Examiner's Use (v) Calculate the relative formula mass of iron oxide, Fe3O4. Show your working. [2] (b) Complete the bonding diagram below to show • the chemical symbols of the elements in a molecule of ammonia, • the arrangement of the outer electrons of each atom. [3]

4 © UCLES 2011 0653/31/O/N/11 For Examiner's Use 2 The golden lion tamarin is a species of monkey that lives in forests in Brazil. Its diet includes fruits and nectar from trees. Its predators include snakes, bamboo rats and owls. (a) (i) In the space below, construct a food web involving golden lion tamarins. [3] (ii) Using your knowledge of energy flow through food chains, explain why predators such as owls are usually rarer than the prey on which they feed. [2]

5 © UCLES 2011 0653/31/O/N/11 [Turn over For Examiner's Use (b) Golden lion tamarins are important for the dispersal of seeds from many different species of trees. They eat the fruits and then egest the seeds in their faeces. An investigation was carried out into the distances that golden lion tamarins dispersed seeds from trees. Fig. 2.1 shows the results of a study in which the distances of the tamarin’s faeces from one tree were measured. 0 50 100 150 200 250 300 distance from one tree / m 350 400 450 500 550 600 percentage of tamarins’ faeces 40 30 20 10 0 Fig. 2.1 (i) Describe the distribution of golden lion tamarin faeces in relation to this tree. [2] (ii) Suggest how the dispersal of seeds away from the tree, in golden lion tamarin faeces, could benefit the young plants that grow from the seeds. [3]

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7 © UCLES 2011 0653/31/O/N/11 [Turn over For Examiner's Use 3 Fig. 3.1 shows two cars. A B Fig. 3.1 (a) Explain which of these cars, A or B, is less likely to overturn if it goes round a corner at high speed. [2] (b) Car B took 1.5 hours to complete a race of 330 kilometres. Calculate the average speed of the car in kilometres per hour. State the formula that you use and show your working. formula used working [2]

8 © UCLES 2011 0653/31/O/N/11 For Examiner's Use (c) Fig. 3.2 shows the speed-time graph for the racing car over a short period. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 speed m / s time / s 50 40 30 20 10 0 B A C Fig. 3.2 (i) Describe the motion of the racing car during section B, section C. [2] (ii) Calculate the distance travelled over the first 10 seconds. Show your working. [2] (iii) The car is accelerating during section A. Calculate the acceleration. Show your working. [2]

9 © UCLES 2011 0653/31/O/N/11 [Turn over For Examiner's Use (iv) The car and driver have a total mass of 1500 kg. Calculate the force that produced the acceleration during section A. State the formula that you use and show your working. formula used working [2]

10 © UCLES 2011 0653/31/O/N/11 For Examiner's Use 4 (a) Fig. 4.1 shows some of the structures involved in a reflex action. hot pan R S Q P Fig. 4.1 (i) State the letter that is labelling each of these structures. a receptor a sensory neurone [2] (ii) On Fig. 4.1, draw one arrow on structure R and one arrow on structure S to show the direction in which a nerve impulse travels. [1] (iii) On Fig. 4.1, label one structure that is part of the central nervous system. [1] (iv) In this reflex action, touching the hot pan causes arm muscles to contract and move the arm away. Describe one advantage of this being a reflex action, rather than a voluntary action. [1] (b) Each neurone has a nucleus, which contains chromosomes made of DNA. (i) Name one type of cell in the human body that does not contain a nucleus. [1] (ii) In humans, a sperm cell has 23 chromosomes. Suggest the number of chromosomes that is present in a neurone. [1]

11 © UCLES 2011 0653/31/O/N/11 [Turn over For Examiner's Use 5 (a) Fig. 5.1 shows a piece of magnesium ribbon which a student has just dropped into a container of dilute sulfuric acid. dilute sulfuric acid magnesium Fig. 5.1 (i) State how an increase in temperature will change the rate at which the magnesium and acid react. [1] (ii) Explain your answer to (i) in terms of particles. [2] (b) Sulfuric acid containers are often made of poly(ethene). Poly(ethene) is a polymer which is formed from hydrocarbon monomers. (i) Suggest one property of poly(ethene) which makes it suitable for making sulfuric acid containers. [1] (ii) Ethene is an unsaturated hydrocarbon which is manufactured from saturated hydrocarbons by cracking. Outline the process of cracking. [2]

12 © UCLES 2011 0653/31/O/N/11 For Examiner's Use 6 (a) Fig. 6.1 shows the circuit diagram of a circuit constructed by a student. Ammeters A1, A2, A3, A4 and A5 are used to measure current. A1 A3 A2 A4 A5 X Y 2 Ω 4 Ω 2 Ω Fig. 6.1 (i) The readings on A2, A3 and A5 are shown in Table 6.1. Table 6.1 Ammeter Reading A2 2 A A3 6 A A5 8 A State the readings on A1 and A4. A1 A4 [2] (ii) The power input to one of the 2 Ω resistors is 72 W. Calculate how many joules of energy are transferred in 20 seconds. State the formula that you use and show your working. formula used working [2]

13 © UCLES 2011 0653/31/O/N/11 [Turn over For Examiner's Use (iii) Calculate the total resistance between X and Y. State the formula that you use and show your working. formula used working [3] (b) Transformers increase the voltage of the electricity generated at a power station before transmission through power lines. (i) State why this is done. [1] (ii) A transformer changes the voltage from 25 000 V to 600 000 V. Use the equation Vp / Vs = Np / Ns to calculate the ratio of the number of turns on the primary coil to the number on the secondary coil. [2]

14 © UCLES 2011 0653/31/O/N/11 For Examiner's Use 7 (a) Table 7.1 shows some information about enzymes found in the human alimentary canal. Complete the table. Table 7.1 enzyme one site of action type of nutrient that is broken down product that is formed mouth protein [3] (b) In some parts of the world, people are unable to get enough food or to eat a balanced diet. Young children in some regions of Asia may have a diet that consists mostly of rice, while in some parts of Africa a young child's diet may consist mostly of cassava. Table 7.2 shows the main nutrients present in 100 g of white rice and 100 g of cassava. Table 7.2 nutrient white rice cassava protein / g 5.0 1.2 carbohydrate / g 58.6 34.7 fat / g 0.4 0.3 (i) A diet that consists mostly of rice is better for a young child than a diet that consists mostly of cassava. Use the information in Table 7.2 to explain one reason why this is so. [2]

15 © UCLES 2011 0653/31/O/N/11 [Turn over For Examiner's Use (ii) Carbohydrates include sugars and starch. Describe how a student could test a sample of cooked rice to find out if it contains reducing sugar. [3] (iii) The parts of a cassava plant that are used as food are the roots, which store carbohydrate in the form of starch. The cells in the cassava roots are provided with carbohydrates that have been made by photosynthesis in the leaves. Describe how carbohydrates that have been made in the cassava plant's leaves are transported to the roots. [2]

16 © UCLES 2011 0653/31/O/N/11 For Examiner's Use 8 Fig. 8.1 shows some data about the percentage composition by mass of the Earth’s crust. Al all other elements (18 %) Si (27 %) O (47 %) Fig. 8.1 (a) (i) State the percentage by mass of aluminium in the Earth’s crust. [1] (ii) State which of the following numbers is most likely to represent the number of elements in the section labelled all other elements in Fig. 8.1. 39 89 139 1089 Explain briefly how you chose your answer. number explanation [1]

17 © UCLES 2011 0653/31/O/N/11 [Turn over For Examiner's Use (b) Aluminium metal may be obtained by the electrolysis of molten aluminium oxide. Fig. 8.2 shows a simplified diagram of this process. electrons from power supply moving towards aluminium ions electrons from oxide ions moving towards the power supply power supply cathode anode molten mixture containing Al 3+ and O 2– Fig. 8.2 Electrons move through the connecting wires in the directions shown in Fig. 8.2, and ions are converted into uncharged atoms at the surfaces of the electrodes. (i) Explain briefly why the mixture containing aluminium oxide must be kept molten. [1] (ii) Explain briefly why oxygen atoms are formed at the anode and not the cathode. [2] (iii) Explain why, when six electrons move around the circuit, two aluminium atoms and three oxygen atoms are formed. [3]

18 © UCLES 2011 0653/31/O/N/11 For Examiner's Use 9 (a) Some types of food are treated with gamma radiation. Low doses of radiation slow down the ripening processes in fresh fruit, whilst higher doses of radiation kill the microbes that make food decay. (i) Explain why gamma radiation can be used for this, even when the fruit is packed in boxes. [1] (ii) Complete the sentences below by crossing out the incorrect words in each box. the same number Isotopes of the same element have atoms with different numbers of protons the same number and different numbers of neutrons. [1] (iii) Fig. 9.1 shows how a conveyor belt can be used to move the fresh fruit past the radioactive source. gamma source fresh fruit in fresh fruit out concrete concrete fresh fruit fresh fruit view from above Fig. 9.1 Suggest why concrete is used to surround the radioactive source. [1]

19 © UCLES 2011 0653/31/O/N/11 [Turn over For Examiner's Use (b) Some people may not like the idea of eating fruit which has been treated with radiation. They wrongly think that the food will be radioactive. (i) Describe one way in which a scientist could show that the food is not radioactive. [1] (ii) Explain why the food will not be radioactive. [1]

20 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. © UCLES 2011 0653/31/O/N/11 Group 140 Ce Cerium 58 141 Pr Praseodymium 59 144 Nd Neodymium 60 Pm Promethium 61 150 Sm Samarium 62 152 Eu Europium 63 157 Gd Gadolinium 64 159 Tb Terbium 65 162 Dy Dysprosium 66 165 Ho Holmium 67 167 Er Erbium 68 169 Tm Thulium 69 173 Yb Ytterbium 70 175 Lu Lutetium 71 232 Th Thorium 90 Pa Protactinium 91 238 U Uranium 92 Np Neptunium 93 Pu Plutonium 94 Am Americium 95 Cm Curium 96 Bk Berkelium 97 Cf Californium 98 Es Einsteinium 99 Fm Fermium 100 Md Mendelevium 101 No Nobelium 102 Lr Lawrencium 103 1 H Hydrogen 1 7 Li Lithium 3 23 Na Sodium 11 24 Mg Magnesium 12 40 Ca Calcium 20 45 Sc Scandium 21 48 Ti Titanium 22 51 V Vanadium 23 52 Cr Chromium 24 55 Mn Manganese 25 56 Fe Iron 26 59 Co Cobalt 27 59 Ni Nickel 28 64 Cu Copper 29 65 Zn Zinc 30 70 Ga Gallium 31 27 Al Aluminium 13 11 B Boron 5 12 C Carbon 6 14 N Nitrogen 7 16 O Oxygen 8 19 F Fluorine 9 28 Si Silicon 14 31 P Phosphorus 15 32 S Sulfur 16 35.5 Cl Chlorine 17 40 Ar Argon 18 20 Ne Neon 10 4 He Helium 2 73 Ge Germanium 32 75 As Arsenic 33 79 Se Selenium 34 80 Br Bromine 35 84 Kr Krypton 36 39 K Potassium 19 88 Sr Strontium 38 89 Y Yttrium 39 91 Zr Zirconium 40 93 Nb Niobium 41 96 Mo Molybdenum 42 Tc Technetium 43 101 Ru Ruthenium 44 103 Rh Rhodium 45 106 Pd Palladium 46 108 Ag Silver 47 112 Cd Cadmium 48 115 In Indium 49 119 Sn Tin 50 122 Sb Antimony 51 128 Te Tellurium 52 127 I Iodine 53 131 Xe Xenon 54 137 Ba Barium 56 139 La Lanthanum 57 * 178 Hf Hafnium 72 181 Ta Tantalum 73 184 W Tungsten 74 186 Re Rhenium 75 190 Os Osmium 76 192 Ir Iridium 77 195 Pt Platinum 78 197 Au Gold 79 201 Hg Mercury 80 204 Tl Thallium 81 207 Pb Lead 82 209 Bi Bismuth 83 Po Polonium 84 At Astatine 85 Rn Radon 86 Fr Francium 87 227 Ac Actinium 89 9 Be Beryllium 4 I II III IV V VI VII 0 85 Rb Rubidium 37 133 Cs Caesium 55 226 Ra Radium 88 The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.). a X b a = relative atomic mass X = atomic symbol b = proton (atomic) number Key *58-71 Lanthanoid series 90-103 Actinoid series DATA SHEET The Periodic Table of the Elements

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2011 question paper for the guidance of teachers 0653 COMBINED SCIENCE 0653/31 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. • Cambridge will not enter into discussions or correspondence in connection with these mark schemes. Cambridge is publishing the mark schemes for the October/November 2011 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 IGCSE – October/November 2011 0653 31 © University of Cambridge International Examinations 2011 1 (a) (i) speeds up reactions ; provides lower (activation) energy route ; without being chemically altered / owtte ; [max 2] (reject does not take part in the reaction) (ii) transition (elements) ; [1] (iii) Fe3O4 + 4H2 → 3Fe + 4H2O ;; [2] (allow 1 mark for 4H2 and 4H2O and then 1 mark for 3Fe) (iv) reduced ; reduction is electron gain ; positive (iron) ions are discharged / gain electrons ; [max 2] (v) 56 × 3 / 16 × 4 ; = 232 ; [2] (b) symbols shown in correct atoms ; three bond pairs around central atom ; lone pair correctly shown ; [3] [Total: 12] 2 (a) (i) trees (fruit and nectar) golden lion tamarins bamboo rats snakes owls plants and tamarins correct ; all three predators correct ; all arrows in right direction ; [3] (ii) energy lost, between trophic levels / as you go up the chain ; as heat / in respiration / other way in which energy is lost ; the idea that there is less energy for (top) predators ; [max 2]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 31 © University of Cambridge International Examinations 2011 (b) (i) fewer faeces further from tree ; furthest distance from tree is 400 m ; figures quoted, e.g. 31 % of faeces deposited within 50 m of tree ; [max 2] (ii) faeces provide nutrients for, young plants / seedlings (not seeds) ; less competition (for seedlings) away from parent tree ; example of factors competed for e.g. light, water, nutrients ; help to colonise new areas ; [max 3] [Total: 10] 3 (a) (car B – no mark) low to ground / low height ; low centre of mass ; [2] (b) (speed =) distance / time ; (allow accepted symbols but reject use of units as symbols) = 330 / 1.5 = 220 km / h ; [2] (c) (i) B – constant speed ; C – decelerating (negative) acceleration ; [2] (ii) distance = area under graph / (6 × 40 × 0.5) + (4 × 40) ; = 280 m ; [2] (iii) acceleration = change in speed ÷ time / ref. to gradient of A / 40 ÷ 6 ; = 6.67 m / s2 ; [2] (iv) force = mass × acceleration ; = 1500 × 6.67 = 10 005 N ; [2] [Total: 12] 4 (a) (i) Q ; R ; [2] (ii) arrow going upwards on R (towards spinal cord) and downwards on S ; [1] (iii) label to spinal cord ; [1] (iv) faster / less time for damage to be done to hand ; [1] (b) (i) red blood cell ; [1] (ii) 46 ; [1] [Total: 7]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 31 © University of Cambridge International Examinations 2011 5 (a) (i) rate increases / or implied e.g. gas given off more quickly ; [1] (ii) particles / ions / molecules move faster / have increased K.E. ; reference to increased collision frequency with magnesium ; [2] (b) (i) unreactive (with acid) / not brittle ; [1] reject references to rusting (ii) (saturated hydrocarbons) heated / vaporised ; contacted with catalyst ; [2] [Total: 6] 6 (a) (i) A1 = 8 (A), A4 = 2 (A) ;; [2] (ii) energy = power × time ; 72 × 20 = 1440 J ; [2] (iii) 1 ÷ R = 1 ÷ R1 + 1 ÷ R2 ; = 1 ÷ 6 + 1 ÷ 2 ; (R =) 1.5 Ω ; [3] (b) (i) reduce energy losses ; [1] (ii) (Np ÷ Ns =) 25 000 ÷ 600 000 ; = 1 : 24 ; [2] [Total: 10] 7 (a) enzyme one site of action type of nutrient that is broken down product that is formed amylase mouth starch maltose protease / trypsin / pepsin stomach / small intestine (see note below) protein amino acids note: if protease given, allow either stomach or small intestine if trypsin, must be small intestine if pepsin, must be stomach one mark for any two correct ;;; [3]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 31 © University of Cambridge International Examinations 2011 (b) (i) (rice has) more protein ; needed for growth ; [2] (ii) add Benedict's solution / Fehlings solution ; heat ; brick red / orange colour indicates sugar present ; [3] (iii) as sugar / sucrose ; in phloem ; [2] [Total: 10] 8 (a) (i) 8 (%) ; [1] (ii) (89) answer related logically to number of elements in Periodic Table ; [1] (b) (i) so ions can move / if solid, ions could not move / so that it can be an electrolyte / so that it will conduct charge (not electrons) ; [1] (ii) anode is positively charged ; attracts negative (oxide) ions / opposite charges attract / would be repelled from negative cathode ; [2] (iii) Al3+ (ions) gain electrons / O2– (ions) lose electrons ; Al3+ gains three electrons / O2– loses two electrons ; some relevant logical statement linking to six electrons ; [3] e.g. so if six electrons then number of Al atoms is 6 ÷ 3 = 2 so six electrons must be provided by 6 ÷ 2 = 3 oxide ions [Total: 8] 9 (a) (i) (gamma able) to penetrate the food / packaging ; [1] (ii) ‘the same number’ and ‘different numbers’ (both required in this order) ; [1] (iii) to protect workforce / stop radiation escaping ; [1] (b) (i) use Geiger counter / other correct instrument to measure radiation emitted ; [1] (ii) radiation emitted by unstable radioactive atoms / (radiated) food does not contain unstable radioactive atoms ; [1] [Total: 5]