Cambridge IGCSE Science - Combined 0653 — 2008 Oct/Nov Paper 3 · Variant 1

This document consists of 18 printed pages and 2 blank pages. IB08 11_0653_03/4RP © UCLES 2008 [Turn over *7199395811* 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 0653/03 Paper 3 (Extended) October/November 2008 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

3 © UCLES 2008 0653/03/O/N/08 [Turn over For Examiner's Use 1 Fig. 1.1 shows a food web. mice pigeons insects small birds hawks plant seeds plant leaves caterpillars Fig. 1.1 (a) (i) State what the arrows in Fig. 1.1 represent. [1] (ii) The longest food chain in Fig. 1.1 has four organisms. Explain why it is rare for food chains to be longer than this. [2] (b) Describe how an atom of carbon in a glucose molecule in an insect could become part of a glucose molecule in a plant leaf. [4]

4 © UCLES 2008 0653/03/O/N/08 For Examiner's Use 2 (a) Two inflated rubber rings, one black and one white, are left on a hot beach in the sun. Fig. 2.1 Explain why the temperature of the air inside the black rubber ring rises more quickly than that in the white rubber ring. [2] (b) Someone has left a glass bottle on the beach. The curved glass acts like a lens focussing the sun’s rays. Complete the light rays on Fig. 2.2 to show what happens to rays of light after they have passed through a convex lens. Fig. 2.2 [2]

5 © UCLES 2008 0653/03/O/N/08 [Turn over For Examiner's Use (c) The power of the waves is used as a renewable source of energy. Suggest how the motion of the waves can be converted to electrical energy. [2] (d) A girl collects two pebbles of the same size from the beach but one seems to be heavier than the other. How could she measure the densities of the two pebbles? [3]

6 © UCLES 2008 0653/03/O/N/08 For Examiner's Use 3 The chemical symbol of magnesium is shown below. Mg 24 12 (a) Draw a labelled diagram of an atom of magnesium. Your diagram should show the numbers of nucleons and the electron configuration. [2] (b) Magnesium is produced industrially by the electrolysis of molten magnesium chloride. Fig. 3.1 shows a simplified diagram of this process. molten magnesium chloride – + Mg2+ Cl– Fig. 3.1 (i) Describe, in terms of ions and electrons, what happens at the surface of the cathode. [2]

7 © UCLES 2008 0653/03/O/N/08 [Turn over For Examiner's Use (ii) Use the information in Fig. 3.1 to explain why the chemical formula of magnesium chloride is MgCl2. [1] (c) A student added magnesium to dilute hydrochloric acid as shown in Fig. 3.2. dilute hydrochloric acid magnesium Fig. 3.2 (i) Explain, in terms of electrons, why the magnesium atoms in the reaction in Fig. 3.2 are said to be oxidised. [2] (ii) Explain, in terms of ions, why the pH of the mixture in Fig. 3.2 increases when magnesium is added to the acid. [2]

9 © UCLES 2008 0653/03/O/N/08 [Turn over For Examiner's Use 4 Fig. 4.1 shows part of the male reproductive system. A B C D Fig. 4.1 (a) (i) Name the parts labelled A and B. A B [2] (ii) Describe the functions of parts C and D. C D [2] (iii) On Fig. 4.1, write the letter X to show the part of the reproductive system which is cut or tied when a man has a sterilisation operation. [1] (b) Humans reproduce using sexual reproduction. Sexual reproduction produces offspring that are genetically different from each other and from their parents. Explain how this can be an advantage to a species of organism. [3]

10 © UCLES 2008 0653/03/O/N/08 For Examiner's Use 5 (a) Fig. 5.1 shows two cars A and B. Car A produces exhaust gases which appear black. The exhaust gases from car B cannot be seen. Both cars have engines which use diesel (gas oil) which is a hydrocarbon fuel. car A car B Fig. 5.1 (i) Describe briefly how hydrocarbon fuels like diesel are obtained. [2] (ii) The formula of a typical molecule in diesel is C13H28. Calculate the relative molecular mass, Mr, of C13H28. Show your working. [2]

11 © UCLES 2008 0653/03/O/N/08 [Turn over For Examiner's Use (b) The energy needed to move cars is provided by the combustion of the fuel. Air must be supplied to the engine for this combustion to occur. Fig. 5.2 shows a bar chart of the main gases in a sample of dry air. 90 80 70 60 50 40 30 20 10 0 % by volume R S argon carbon dioxide gases Fig. 5.2 (i) Explain which gas shown in Fig. 5.2 reacts with the diesel fuel in car engines. [1] (ii) Suggest the name of the black substance in the exhaust gases of car A in Fig. 5.1, and explain briefly how it is formed. [2] (iii) Explain why car engines should never be left running for long periods of time in a garage or other enclosed space where there are people. [2]

12 © UCLES 2008 0653/03/O/N/08 For Examiner's Use 6 (a) The isotope radon–220 is radioactive. A sample was investigated to find its half-life. The activity of the isotope was measured every 30 seconds for 6 minutes. The results are shown in Fig. 6.1. 0 50 100 150 200 250 300 350 time / seconds 22 000 20 000 18 000 16 000 14 000 12 000 10 000 8000 6000 4000 2000 0 activity / counts per second Fig. 6.1 Use the graph to calculate the half-life of the isotope. Show your working on the graph. [2]

13 © UCLES 2008 0653/03/O/N/08 [Turn over For Examiner's Use (b) There are several isotopes of radon. State the meaning of the word isotope. [1] (c) Radon-220 emits alpha radiation. Explain why alpha radiation is dangerous to human beings. [4]

14 © UCLES 2008 0653/03/O/N/08 For Examiner's Use 7 This article appeared in a newspaper in Pakistan in 2006. Many more people in Pakistan and India are developing diabetes. This is an illness where the regulation of blood glucose does not work properly. It is dangerous because rising levels of glucose in the blood can damage cells in many parts of the body, including the blood system and the eyes. Doctors think that the increase in diabetes is happening because people are eating more fast food. Where they used to eat a lot of rice and lentils, they are now eating more fried foods and greasy take-aways. As well as increasing the risk of diabetes, it is causing an increase in obesity. This also increases the risk of heart disease. (a) The regulation of blood glucose is part of homeostasis. Explain the meaning of the term homeostasis. [2] (b) (i) Name the hormone that is produced when the blood glucose level rises, and which helps to bring it back down to normal. [1] (ii) Describe how the hormone reduces the amount of glucose in the blood. [2]

15 © UCLES 2008 0653/03/O/N/08 [Turn over For Examiner's Use (c) When a person with diabetes eats food containing sugar, the concentration of glucose in their blood increases. Using what you know about osmosis, explain how this might cause damage to body cells. [2] (d) (i) Suggest why eating foods containing a lot of fat, rather than eating lentils and rice, can lead to obesity. [2] (ii) Explain how a poor diet can increase the risk of a heart attack. [2]

16 © UCLES 2008 0653/03/O/N/08 For Examiner's Use 8 (a) Fig. 8.1 shows part of the Periodic Table. The letters are not the chemical symbols of elements. A E F G B C D H Fig. 8.1 Choose one of the letters from A to H, which shows a metal which reacts vigorously with cold water an element whose atoms have only one electron shell [2] (b) Calcium carbonate, CaCO3, is an important compound used in many industries. A student used the apparatus in Fig. 8.2 to investigate the thermal decomposition of calcium carbonate. strong heat calcium carbonate tube T solution S Fig. 8.2

17 © UCLES 2008 0653/03/O/N/08 [Turn over For Examiner's Use (i) Write a word equation and a balanced symbolic equation for the reaction which occurs when calcium carbonate is heated strongly. word equation symbolic equation [3] (ii) Name solution S in Fig. 8.2, and predict what would be observed during the reaction. [1] (iii) Describe how the student could test the solid which remains in tube T to find out if all the calcium carbonate had reacted. [2] (iv) Why are large amounts of calcium carbonate sometimes spread on soil which is going to be used for growing crops? [1]

18 © UCLES 2008 0653/03/O/N/08 For Examiner's Use 9 (a) A student has six resistors as shown in Fig. 9.1. 2 Ω 4 Ω 6 Ω 2 Ω 4 Ω 6 Ω Fig. 9.1 (i) Describe how he can combine two of these resistors to get a total resistance of 10 ohms. [1] (ii) Explain how he can combine two of these resistors to get a total resistance of three ohms. [3] (b) Electricity can be generated by turning a coil of copper wire in a magnetic field. (i) Describe two ways to increase the voltage produced by this generator. 1 2 [2]

19 © UCLES 2008 0653/03/O/N/08 For Examiner's Use (ii) Generators can supply an alternating current which has a frequency of 50 Hz. On the grid below, sketch a graph to show the current produced by this alternating current generator during a period of 0.1 seconds. 0 time / s voltage / V [3] (c) Electricity is often transmitted through overhead power cables hung from pylons. If these cables are put up on a hot summer day, they are hung loosely from the pylons as shown in Fig. 9.2. Fig. 9.2 Suggest why they are hung loosely. [2]

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 2008 0653/03/O/N/08 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 Sulphur 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 2008 question paper 0653 COMBINED SCIENCE 0653/03 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. All Examiners are instructed that alternative correct answers and unexpected approaches in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and skills demonstrated. 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 October/November 2008 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 Syllabus Paper IGCSE – October/November 2008 0653 3 © UCLES 2008 1 (a) (i) energy (transfer) ; [1] (ii) energy lost between, organisms / levels / links in the chain ; detail of how it is lost ; not enough energy available to support, fifth link / predator of hawks ; [max 2] (b) respiration (in insect) ; releases carbon dioxide (to the air) ; carbon dioxide absorbed by plant ; photosynthesis (in plant) ; combines carbon dioxide with water ; (produces glucose) in chloroplast ; alternative starting point: insect dies and, is decomposed/decays ; respiration (of decomposers) ; then points 2 onward as above [max 4] [Total: 7] 2 (a) black surfaces are better absorbers ; of, radiation / heat ; more heat means, particles move faster / bigger temperature rise ; [max 2] (b) rays drawn as straight lines ; rays of light come together to a focus ; [2] (c) (up/down) motion / kinetic energy, of waves ; makes generator / dynamo / magnet in coil, turn (to produce electricity) ; [2] (d) measure mass and volume ; by using Eureka can / displacement method described ; divide mass by volume ; [3] [Total: 9]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2008 0653 3 © UCLES 2008 3 (a) 12 protons labelled and 12 neutrons labelled ; electrons shown in three energy levels 2, 8, 2 ; [max 2] (b) (i) magnesium ions (are involved) ; (magnesium ions) gain two electrons each ; [2] (ii) reference to charge balance / two negative charges on two chlorides are needed to balance the double positive on magnesium ; [1] (c) (i) magnesium (atoms), become positive ions / lose electrons ; electron loss is oxidation ; [2] (ii) H+ ions are reacting / concentration of H+ ions is decreasing / hydrogen is lost ; the lower the H+ concentration the higher the pH ; [2] [Total: 9] 4 (a) (i) A urethra ; B bladder ; [2] (ii) C – carries urine (from kidneys to bladder) ; D – makes sperm ; [2] (iii) X on sperm duct ; [1] (b) if environment changes ; example – disease / predator / change in climate ; some individuals may survive / not all will be killed ; because they have advantageous characteristics ; can breed and pass on these characteristics to their offspring ; idea that genetic disease may not be passed to offspring ; [max 3] [Total: 8]

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2008 0653 3 © UCLES 2008 5 (a) (i) crude oil / petroleum (extracted from Earth) ; oil is, refined / made into simpler mixtures ; by fractional distillation ; oil is heated ; different products, distil / are collected, according to boiling point / at different positions ; [max 2] (ii) (13 x 12 ) + (28 x 1) ; = 184 ; [2] (b) (i) gas S because it is oxygen ; [1] (ii) carbon / soot ; results from incomplete combustion ; [2] (iii) reference to carbon monoxide / nitrogen dioxide ; toxic / detail e.g. (CO) attaches to haemoglobin ; [2] [Total: 9] 6 (a) working ; 55 s plus or minus 2 ; [2] (b) same number of protons but different number of neutrons ; [1] (c) dangerous when, ingested / breathed in / inside the body ; highly ionising ; because, large mass / large charge / large particle / is helium nucleus ; removes electrons ; damages DNA / causes mutations ; causes cancer ; destroys / damages, cells ; [max 4] [Total: 7]

Page 5 Mark Scheme Syllabus Paper IGCSE – October/November 2008 0653 3 © UCLES 2008 7 (a) keeping constant / keeping stable / maintaining ; internal environment / environment of cells / conditions in the body ; another example, e.g. temperature / water / salt ; [max 2] (b) (i) insulin ; [1] (ii) affects liver ; which removes glucose from the blood ; stores it as glycogen / glucose converted to glycogen ; [max 2] (c) higher concentration (of sugar) outside cell than inside ; (cell) membrane is partially permeable ; so water moves out of cells ; cells, short of water / shrink / dehydrated ; [max 2] (d) (i) a lot of, energy / calories / kilojoules, in fat ; lentils and rice mostly, carbohydrate / starch ; less energy per gram in carbohydrates than fat ; [max 2] (ii) fatty diet linked to development of (coronary) heart disease ; build up of cholesterol in arteries ; blockage of coronary artery ; stops oxygen getting to heart (muscle) ; heart muscle stops working ; [max 2] [Total: 11] 8 (a) B, C or D ; A ; [2] (b) (i) calcium carbonate → calcium oxide + carbon dioxide; all formulae in equation match words and are correct ; CaCO3 → CaO + CO2 ; [3] (ii) limewater / calcium hydroxide (solution), goes cloudy; [1] (iii) add (dilute) acid / heat further ; if (more) gas is produced then not all calcium carbonate has reacted / ora ; [2] (iv) soil is too acidic / pH too low (for the intended crop)/calcium carbonate reacts with excess acid / neutralises ; [1] [Total: 9]

Page 6 Mark Scheme Syllabus Paper IGCSE – October/November 2008 0653 3 © UCLES 2008 9 (a) (i) 6 Ω and 4 Ω in series ; [1] (ii) 6 Ω and 6 Ω ; in parallel ; 1/R = 1/6 + 1/6 = 2/6 ; [3] (b) (i) increase magnetic field ; turn coil faster ; increase number of turns ; [max 2] (ii) sine wave above and below x axis ; (approx) constant amplitude ; five waves ; [3] (c) contract, in winter/when cold ; cables pulled closer together / explanation of damage caused / increased tension ; [2] [Total: 11]