Cambridge IGCSE Science - Combined 0653 — 2011 Oct/Nov Paper 3 · Variant 2

This document consists of 22 printed pages and 2 blank pages. IB11 11_0653_32/6RP © UCLES 2011 [Turn over *5582760062* 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 0653/32 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 24. 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 0653/32/O/N/11 For Examiner's Use 1 Coral reefs are found in shallow seawater. Limestone is a common type of rock found in the Earth’s crust. Both coral reefs and limestone are made mainly of the ionic compound, calcium carbonate. (a) A student uses the apparatus shown in Fig. 1.1 to test a rock sample to discover whether or not it is limestone. large side-arm tube dilute hydrochloric acid rock sample limewater small test-tube Fig. 1.1 The student observed that a gas was given off and that the limewater in the small test-tube became cloudy. (i) Name the gas that was given off. [1] (ii) Explain whether or not the student gained enough evidence from the result of his test to show that the rock sample is made of limestone. [2] (b) In recent years, the amount of carbon dioxide in the atmosphere has increased. This has contributed to a decrease in the average pH of seawater. During this period, many coral reefs have become weakened and damaged. (i) Explain why increased levels of carbon dioxide in the atmosphere could cause the average pH of the sea to decrease. [2]

3 © UCLES 2011 0653/32/O/N/11 [Turn over For Examiner's Use (ii) Suggest why a decrease in the average pH of seawater could damage coral reefs. [1]

4 © UCLES 2011 0653/32/O/N/11 For Examiner's Use 2 Most cells obtain energy from carbohydrates and other nutrients by aerobic respiration. (a) Write the word equation for aerobic respiration. [2] (b) Describe how oxygen is transported from the lungs to a cell in a human muscle. [2] (c) When a person runs, muscles generate heat energy, which increases the body temperature. Body temperature can be lowered by sweating. The core temperature of an athlete was measured as she ran steadily for 120 minutes, drinking no fluids while running. She repeated the run the next day, but this time drank fluids throughout the run. The environmental temperature and humidity were the same on both days. The results are shown in Fig. 2.1. 0 30 60 90 120 40 39 38 37 36 running time / minutes core body temperature / °C no fluids drunk fluids drunk Fig. 2.1

5 © UCLES 2011 0653/32/O/N/11 [Turn over For Examiner's Use (i) Explain how sweating can reduce body temperature. [2] (ii) Compare the body temperature of the athlete when she ran without drinking fluids to her body temperature when she ran while drinking fluids. [2] (iii) Suggest an explanation for the differences you have described in (ii). [2]

6 © UCLES 2011 0653/32/O/N/11 For Examiner's Use 3 Yaks are animals that live in the cold mountainous region of the Himalayas. Fig. 3.1 Fig. 3.1 shows a yak. (a) Explain how the long hair of the yak keeps it warm during the cold weather. [2] (b) Yak dung is commonly burned as a fuel in the Himalayas. However, it is slowly being replaced by kerosene. State and explain one environmental reason why yak dung is a better fuel to use than kerosene. [2]

7 © UCLES 2011 0653/32/O/N/11 [Turn over For Examiner's Use (c) Yaks communicate with each other using low frequency sounds that humans can hear. (i) Suggest a possible frequency for this sound. [1] (ii) Explain what is happening when this sound travels through the air. You may use a diagram to help you answer this question. [2]

8 © UCLES 2011 0653/32/O/N/11 For Examiner's Use 4 Nordic gold is an alloy of four metals used to make coins. Table 4.1 shows information about the metals contained in Nordic gold. Table 4.1 metal % by mass in Nordic gold compound from which the metal is extracted aluminium 5 Al2O3 copper 89 CuFeS2 tin 1 SnO2 zinc 5 ZnS (a) In the right hand column, the elements present in compounds can be identified by their symbols. Name a metallic element present in one of the compounds in Table 4.1 which is not present in Nordic gold. [1] (b) The method used to extract a metal from its compound depends on the reactivity of the metal. (i) Tin may be extracted from tin oxide, SnO2, by heating a mixture of tin oxide and carbon. The other product of this reaction is carbon monoxide, CO. Construct a balanced, symbolic equation for this reaction. [2]

9 © UCLES 2011 0653/32/O/N/11 [Turn over For Examiner's Use (ii) When aluminium oxide is heated with carbon, no reaction occurs. Explain why it is possible to extract tin but not aluminium by heating their oxides with carbon. [2] (iii) Aluminium is extracted from the insoluble compound aluminium oxide by electrolysis. Outline the stages by which solid aluminium oxide, containing aluminium ions, is converted into metallic aluminium, made of aluminium atoms, using electrolysis. [3] (c) (i) Calculate the formula mass of the compound, CuFeS2. Show your working. [1] (ii) A coin made of Nordic gold has a mass of 7.80 g. Calculate the mass of copper in the coin. Show your working. [1]

10 © UCLES 2011 0653/32/O/N/11 For Examiner's Use 5 Fig. 5.1 shows a flower from a sugar cane plant. X Y Fig. 5.1 (a) (i) Name the parts labelled X and Y. X Y [2] (ii) Describe two features of the sugar cane flower which indicate that it is wind-pollinated. 1 2 [2] (iii) Flowers are involved in sexual reproduction. State two ways in which sexual reproduction differs from asexual reproduction. 1 2 [2] (b) In many parts of the world, fields of sugar cane are burned before harvesting. Burning the sugar cane plants releases nitrogen oxides into the air. Explain how this could harm the environment. [3]

11 © UCLES 2011 0653/32/O/N/11 [Turn over BLANK PAGE Please turn over for Question 6.

12 © UCLES 2011 0653/32/O/N/11 For Examiner's Use 6 Sea anemones are animals that live attached to rocks or the sea bed. Fig. 6.1 shows a section through a sea anemone. tentacle tissue containing cells that make enzymes space where digestion takes place Fig. 6.1 (a) Explain the meaning of the term tissue. [2] (b) Sea anemones feed by capturing small animals with their tentacles. The tentacles push the small animal into the space in the middle of the body. The cells lining the space secrete enzymes, which digest the animal. (i) One of the enzymes that is secreted is protease. This breaks down large molecules to small, soluble molecules. State the name of the large molecules that are broken down by protease, the small, soluble molecules produced. [2] (ii) Because sea anemones are small, they do not need a blood system to transport nutrients to all the different cells in their body. Suggest how the small, soluble molecules produced by digestion can spread to all the cells in the sea anemone's body. [2]

13 © UCLES 2011 0653/32/O/N/11 [Turn over For Examiner's Use (c) Sea anemones usually stay firmly fixed to rocks. Because sea anemones do not move around, some people think they are plants. A student looks at a small part of a sea anemone through a microscope. Suggest what the student would observe that would show that a sea anemone is an animal and not a plant. [2]

14 © UCLES 2011 0653/32/O/N/11 For Examiner's Use 7 Fig. 7.1 shows an electric hairdryer. switch 1 switch 2 Fig. 7.1 (a) Fig. 7.2 shows the circuit diagram for the hairdryer. mains power supply M heater motor switch 1 switch 2 Fig. 7.2 (i) State which of the switches must be closed (on) for the heater in the hairdryer to work. [1]

15 © UCLES 2011 0653/32/O/N/11 [Turn over For Examiner's Use (ii) A student wanted to determine the resistance of the heater. Fig. 7.3 shows the circuit he built to measure the current passing through the heater and the potential difference across the heater. A V Fig. 7.3 His experiment did not work because his circuit was incorrect. Draw the correct circuit in the space below. [1] (b) (i) The electricity used in the hairdryer was generated at a power station. Power is transmitted from the power station over large distances. A high voltage is always used. Explain why. [1]

16 © UCLES 2011 0653/32/O/N/11 For Examiner's Use (ii) The high voltage is produced by a transformer. Fig. 7.4 shows a diagram of a simple transformer. primary coil secondary coil 5000 V 10 000 turns 400 000 V Fig. 7.4 Calculate the number of turns in the secondary coil. State the formula that you use and show your working. formula used working number of turns = [2] (iii) Explain how a transformer changes the voltage of an electrical supply. Your explanation should include the terms induced voltage and magnetic field. [3]

17 © UCLES 2011 0653/32/O/N/11 [Turn over For Examiner's Use 8 Hydrocarbons are compounds which contain only the elements hydrogen and carbon. (a) The simplest hydrocarbon is methane, CH4, which is an important fuel. (i) State one natural source of methane. [1] (ii) A free (unbonded) carbon atom has four electrons in its outer shell. State the number of electrons in the outer shell of a carbon atom in a methane molecule. Describe their arrangement. You may wish to draw a diagram to help you answer this question. [2]

18 © UCLES 2011 0653/32/O/N/11 For Examiner's Use (b) Table 8.1 shows the displayed formulae and boiling points of four hydrocarbons, A, B, C and D. Table 8.1 displayed formula boiling point / °C A H C H H C H H C H H H C H H H C H H C H 69 B H H C H H C H H H C H H C H −0.5 C H C H C H C H H H C H H −6.3 D H C H C H C H H H C H H H C H H C H 63 (i) Name a process which could be used to separate a mixture of the four compounds in Table 8.1. [1] (ii) Use the information in Table 8.1 to suggest one way in which the boiling point of a hydrocarbon is affected by its molecular structure. [2]

19 © UCLES 2011 0653/32/O/N/11 [Turn over For Examiner's Use (iii) A bottle contains a colourless liquid which is thought to be either hydrocarbon A or D. Describe a chemical test, and its result, which could be used to identify which hydrocarbon is in the bottle. Explain your choice of test. [3]

20 © UCLES 2011 0653/32/O/N/11 For Examiner's Use 9 (a) An aircraft has a mass of 400 000 kg. It has four engines each capable of producing a maximum force of 300 000 N. Calculate the maximum acceleration of the aircraft. State the formula that you use and show your working. formula working [3] (b) Potato snacks are packed in airtight packets and filled with an unreactive gas at atmospheric pressure. (i) Suggest why an unreactive gas is used, rather than air. [1] (ii) A passenger has a packet of potato snacks in his hand luggage on the aircraft. During the flight, the aircraft cabin is at a pressure less than normal atmospheric pressure. The passenger notices that the packet has expanded. Explain why this happens. [1]

21 © UCLES 2011 0653/32/O/N/11 [Turn over For Examiner's Use (c) A skydiver jumps from an aircraft and falls through the air. Eventually she reaches a constant terminal velocity. When she opens her parachute, her velocity decreases and she falls slowly to the ground. Fig. 9.1 shows how her velocity varies during the fall. 60 50 40 30 20 10 0 0 5 10 15 20 25 30 35 40 45 A B C E time / s velocity m / s D Fig 9.1 (i) State the difference between speed and velocity. [1] (ii) State one region on the graph when she is accelerating. [1] (iii) Is this acceleration constant over this region? Explain your answer. [1] (iv) Give the letter of the point at which the parachute opens. [1] (v) State the terminal velocity before the parachute opens. [1]

22 © UCLES 2011 0653/32/O/N/11 For Examiner's Use (vi) Explain why the skydiver reaches a terminal velocity. [2] (vii) Explain why the open parachute slows down the skydiver. [1]

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24 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 0653/32/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 0653/32 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. • 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 32 © University of Cambridge International Examinations 2011 1 (a) (i) carbon dioxide ; [1] (ii) (there is not enough evidence) result shows that: carbonate present ; but not calcium / need to show it is calcium carbonate ; [2] (b) (i) carbon dioxide dissolves in / reacts with (sea)water / rain ; makes water more acidic / less alkaline; non-metal oxides are acidic ; [max 2] (ii) accept any reasonable attempt at a scientific answer: e.g. calcium carbonate may react with more acidic water / lower pH makes it more difficult for coral to extract ions from sea / coral (polyps) does not survive in more acidic water ; [1] [Total: 6] 2 (a) glucose + oxygen → carbon dioxide + water ; (2 marks for all correct, one mark if any mistake) [2] (b) in the blood / in an artery / in a capillary ; combined with haemoglobin / as oxyhaemoglobin ; in red blood cells ; [max 2] (c) (i) evaporation ; (evaporation) takes heat from body ; [2] (ii) (assume answer refers to not drinking fluid unless otherwise stated) rose higher ; rose faster ; use of comparative figures, e.g. 40.0 ºC and 38.7 ºC ; [max 2] (iii) less sweat produced when no fluids drunk / or reverse argument ; to maintain water content of body / ref. to homeostasis ; [2] [Total: 10] 3 (a) traps layer of air ; (air is a good) insulator ; [2] (b) does not deplete fossil fuel reserves / non-renewable ; idea that dung is carbon neutral / renewable ; kerosene is a hydrocarbon fuel ; [max 2]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 32 © University of Cambridge International Examinations 2011 (c) (i) allow 20 – 100 Hz ; [1] (ii) vibration passes ; from particle to particle ; reference to rarefaction and compression / diagram ; a series of (compressions and rarefactions) / diagram ; [max 2] [Total: 7] 4 (a) iron ; [1] (b) (i) SnO2 + 2C → Sn + 2CO ;; (symbols and balanced) [2] (ii) aluminium more reactive than carbon ; tin less reactive than carbon ; Al more strongly bonded to oxygen ; [max 2] (allow max 1 for the simple statement: aluminium is more reactive) (iii) reference to use of carbon electrodes ; aluminium oxide is melted / dissolved in cryolite ; aluminium ions are positive / are cations ; ions attracted move to negative electrode / cathode ; ions gain electrons from / are discharged at negative electrode ; [max 3] (c) (i) 64 + 56 + 32 × 2 / 184 ; [1] (allow 183.5) (ii) 7.80 × 0.89 = 6.9(42) g (unit required) ; [1] [Total: 10] 5 (a) (i) X – stigma ; Y – anther / stamen ; [2] (ii) stigma, feathery / outside flower / large surface area ; stamen, dangling / outside flower ; no petals ; (allow small petals) [max 2] (iii) (assume answer refers to sexual reproducation unless otherwise stated) involves gametes ; involves fertilisation ; zygote produced ; offspring genetically different / not clones ; [max 2] (b) acid rain ; caused when nitrogen oxides, react with / dissolve in, (rain) water ; damages plants ; damages aquatic animals ; [max 3] [Total: 9]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 32 © University of Cambridge International Examinations 2011 6 (a) group of cells ; carrying out a particular or specific function / are similar cells ; [2] (b) (i) proteins ; amino acids ; [2] (ii) diffusion ; ref to concentration gradient / from high concentration to low concentration ; [2] (c) (assume answer refers to animal cells unless otherwise stated) look at cells (as opposed to whole organism) ; no cell walls ; no large vacuoles ; no chloroplasts ; [max 2] [Total: 8] 7 (a) (i) switch 1 and switch 2 ; [1] (ii) voltmeter in parallel and ammeter in series ; [1] (b) (i) to reduce energy losses ; [1] (ii) Vp ÷ Vs = Np ÷ Ns ; 5 000 ÷ 400 000 = 10 000 ÷ Ns / (Ns=) 800 000 (turns) ; [2] (1 mark for formula and 1 mark for substitution and answer) (iii) ref. to alternating or changing voltage or current ; (in primary coil) produces alternating or changing magnetic field ; reference to alternating or changing magnetic field in core ; induces (alternating) voltage in secondary coil ; idea that size of voltage change depends on (ratio of) turns ; [max 3] [Total: 8] 8 (a) (i) formed as fossil fuel / decomposition of organic matter / from digestive systems of ruminants / sources related to volcanism ; [1] (ii) 8 ; four covalent bonds means four pairs of electrons ; (correct bonding diagram alone gains both marks) [2]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 32 © University of Cambridge International Examinations 2011 (b) (i) fractional distillation / fractionation ; [1] (ii) the larger / heavier / greater surface area of / greater number of atoms in molecules ; the higher the boiling point ; OR unsaturation ; lowers boiling point (for similar molecular size) ; [max 2] (iii) (shake liquid with) bromine / potassium manganate(VII) ; mixture goes colourless if liquid is D ; because D is unsaturated ; [3] (or reverse argument for A) [Total: 9] 9 (a) (force =) mass × acceleration ; acceleration = 1 200 000 / 400 000 ; = 3 m / s2 ; [3] (b) (i) to stop potato snacks oxidizing / reacting ; [1] (ii) pressure inside packet is greater than airplane pressure ; [1] (c) (i) speed has magnitude only / velocity has magnitude and direction ; [1] (ii) A to B / C to D ; [1] (iii) (no) not a straight line ; [1] (iv) C ; [1] (v) 50 m / s ; [1] (vi) the faster the skydiver travels the greater the air resistance ; eventually the air resistance balances the gravitational force ; [2] (vii) parachute increases air resistance ; [1] [Total: 13]