Cambridge IGCSE Science - Combined 0653 — 2011 May/June Paper 3 · Variant 2

This document consists of 23 printed pages and 1 blank page. IB11 06_0653_32/4RP © UCLES 2011 [Turn over *0316013424* For Examiner's Use 1 2 3 4 5 6 7 8 9 10 Total UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/32 Paper 3 (Extended) May/June 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/M/J/11 For Examiner's Use 1 Guanacos are relatives of camels and live in the Andes mountains in South America. They feed on grasses and other plants. They are killed and eaten by pumas. Fig. 1.1 shows a guanaco. Fig. 1.1 (a) Give the correct ecological term for each of the following. (i) all the guanacos that live in a particular area [1] (ii) all the species of animals and plants that live in a particular area [1] (iii) an organism, such as a guanaco or a puma, that feeds on other organisms [1]

3 © UCLES 2011 0653/32/M/J/11 [Turn over For Examiner's Use (b) Guanacos can live at very high altitudes, above 4000 metres. The atmosphere is less dense than at sea level, and it can become very cold. (i) The blood of a guanaco contains four times as many red blood cells per cm3 as the blood of a human. This helps the guanaco to survive in its environment. Suggest an explanation for this. [2] (ii) Explain how the hair of a guanaco can help it to survive in its environment. [2] (c) Guanacos are an endangered species. Their numbers have fallen because of damage to their natural habitat, caused by humans. (i) Suggest two types of human activity that may damage the natural habitat of guanacos. 1 2 [2] (ii) Several countries in South America have conservation programmes to try to increase the numbers of guanacos. Suggest why it is important to conserve guanacos. [2]

4 © UCLES 2011 0653/32/M/J/11 For Examiner's Use 2 (a) A man has dropped a torch (flashlight) down a drain. The torch has disappeared into the horizontal part of the drain as shown in Fig. 2.1. torch drain Fig. 2.1 The torch is still switched on but the man cannot see it. The man lowers a mirror down the drain in order to find his torch. (i) On Fig. 2.1 draw a mirror at the correct place and angle so that the man can see light from the torch. Use this symbol for the mirror. [1] (ii) On Fig. 2.1 draw a ray of light from the torch to the man. [1] (b) The diagrams below show the symbols for three parts of the electrical circuit in the torch. (i) On the line below each diagram state the name of the part. … … … [1]

5 © UCLES 2011 0653/32/M/J/11 [Turn over For Examiner's Use (ii) Draw a circuit diagram to show how these three parts are connected in the torch. [1] (c) Fig. 2.2 shows a torch standing on a table. M shows the position of the centre of mass of the torch. table A B M Fig. 2.2 Explain why the torch is more stable if it stands on end A rather than on end B. You may use diagrams to help your answer. [2]

6 © UCLES 2011 0653/32/M/J/11 For Examiner's Use 3 Lithium and its compounds have many important uses. (a) Fig. 3.1 shows how pieces of lithium metal are stored. Li hydrocarbon oil pieces of lithium Fig. 3.1 State and explain why it is necessary to store lithium in this way. [2] (b) The production of lithium metal involves three main stages. 1 Lithium compounds found in the Earth’s crust are first converted into lithium carbonate, Li2CO3. 2 Lithium carbonate is then converted into lithium chloride, LiCl. 3 Lithium chloride and potassium chloride are melted together and the molten mixture is electrolysed. Fig. 3.2 shows the apparatus and materials which could be used to produce a neutral solution of lithium chloride from lithium carbonate and dilute hydrochloric acid. dilute hydrochloric acid lithium carbonate stirring rod beaker filtering apparatus spatula Fig. 3.2

7 © UCLES 2011 0653/32/M/J/11 [Turn over For Examiner's Use (i) Describe how this apparatus should be used to produce a neutral solution of lithium chloride. [3] (ii) Suggest the word equation for the reaction between lithium carbonate and dilute hydrochloric acid. [1] (c) Fig. 3.3 shows a simplified diagram of the electrolysis of a molten electrolyte containing lithium chloride. low voltage power supply + – molten electrolyte containing lithium chloride Fig. 3.3 (i) Explain why the process of electrolysis would not work if the electrolyte was allowed to solidify. [2]

8 © UCLES 2011 0653/32/M/J/11 For Examiner's Use (ii) Describe how the electron configuration of each lithium ion changes when it arrives at the cathode. You may draw a diagram to help you answer this question. [1]

9 © UCLES 2011 0653/32/M/J/11 [Turn over For Examiner's Use 4 Fig. 4.1 shows a smoke detector that uses the isotope americium-241, which emits alpha radiation. battery electrode electrode Radiation from americium-241 ionises particles in air, allowing an electric current to flow between the two electrodes. Fig. 4.1 Smoke particles stop radiation from reaching the air particles. This causes the current to stop flowing, causing the alarm to sound. (a) Explain why beta or gamma radiation sources would not be suitable for this smoke detector. [2]

10 © UCLES 2011 0653/32/M/J/11 For Examiner's Use (b) Fig. 4.2 is a graph to show how the number of americium-241 atoms inside a source decreases over time. 10 000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 0 100 200 300 400 500 time / years 600 700 800 900 1000 number of americium-241 atoms Fig. 4.2 (i) Calculate the half-life of the americium-241. Show your working. [2] (ii) The battery inside the smoke detector has to be replaced each year. Explain why the americium-241 source will never have to be replaced. [1]

11 © UCLES 2011 0653/32/M/J/11 [Turn over For Examiner's Use 5 Fig. 5.1 shows crude oil and natural gas trapped in underground rocks. The diagram is not drawn to scale. layers of underground rocks natural gas crude oil trees Fig. 5.1 (a) Wood obtained from trees and compounds obtained from crude oil and natural gas can be used as fuels. State two reasons why crude oil and natural gas are examples of fossil fuels but wood is not. 1 2 [2] (b) Hexane, C6H14, is a hydrocarbon which is found in gasoline (car fuel). Show that the relative formula mass of hexane is 86. [1]

12 © UCLES 2011 0653/32/M/J/11 For Examiner's Use (c) Fig. 5.2 shows the balanced equation for the complete combustion of methane. The reactants and products are shown using displayed (graphical) chemical formulae. H H + H H C O O O C O O O + H O H O H H Fig. 5.2 During the reaction, chemical bonds are both broken and formed. (i) On the equation in Fig. 5.2 draw a cross (X) on one of the single covalent bonds which is broken. [1] (ii) When bonds are broken, energy is absorbed. When bonds are formed, energy is released to the surroundings. Explain, in terms of the breaking and formation of chemical bonds, why some chemical reactions are exothermic. [2]

13 © UCLES 2011 0653/32/M/J/11 [Turn over For Examiner's Use (d) In a car engine, the combustion of hydrocarbons produces a mixture of waste (exhaust) gases which are released into the atmosphere. exhaust gases hydrocarbon fuel and air Table 5.1 shows information about some of the gases in a car’s exhaust. Table 5.1 substance in exhaust gases % by volume nitrogen 67 carbon dioxide 12 water vapour 11 carbon monoxide 0.2 (i) Explain why the mixture of exhaust gases contains carbon monoxide. [1] (ii) Suggest why the exhaust gas mixture contains a significant amount of nitrogen. [2]

14 © UCLES 2011 0653/32/M/J/11 For Examiner's Use 6 The human body contains organs made up of many different types of cells and tissues. (a) Write each of these structures in the correct column in the table. eye heart sperm stomach cell tissue organ [2] (b) The internal environment of the human body is kept at a constant temperature of about 37 ºC. Explain why cells work best at this temperature. [2]

15 © UCLES 2011 0653/32/M/J/11 [Turn over For Examiner's Use (c) Bone tissue is made up of cells surrounded by the mineral calcium phosphate. A study was carried out in Brazil into the mineral content of the leg bones of school children between the ages of 10 and 19 years. The mineral content was measured as the mass of mineral per cm3 of bone. Some of the results are shown in Fig. 6.1. 10–11 12–13 14–15 16–17 18–19 1.1 1.0 0.9 0.8 0.7 0.6 0.5 ages / years mineral content / g per cm3 Fig. 6.1 (i) Describe how the mineral content of bone changes between the ages of 10 and 19 years. [2] (ii) Use the information in Fig. 6.1 to explain why a teenager should have a diet containing plenty of dairy products such as milk and cheese. [2] (iii) Bone also contains a protein called collagen. Vitamin C is required to make collagen. Name one food that contains large amounts of vitamin C. [1]

16 © UCLES 2011 0653/32/M/J/11 For Examiner's Use 7 A man wearing a parachute jumps from an aeroplane. There is an upward force and a downward force acting on the man as he begins to fall before using his parachute. The man then opens his parachute. (a) (i) Name the force which remains the same when his parachute opens. [1] (ii) Explain in terms of forces why the man’s speed of fall decreases when the parachute opens. [3] (b) Fig. 7.1 shows the speed-time graph of his fall. 0 20 40 60 80 100 120 12 10 8 6 4 2 0 time / s speed m / s Fig. 7.1 (i) Mark on the graph with the letter Z the point at which the parachute opened. [1] (ii) Mark on the graph with the letter S a point where the man is travelling at constant speed. [1]

17 © UCLES 2011 0653/32/M/J/11 [Turn over For Examiner's Use (iii) Use Fig. 7.1 to calculate the distance travelled by the man between 60 and 80 seconds. Show your working. [2]

18 © UCLES 2011 0653/32/M/J/11 For Examiner's Use 8 A student investigated the reactivity of four metals, calcium, copper, magnesium and an unknown metal A, by comparing the rate at which these metals reacted in water. Fig. 8.1 shows what the student observed during the experiment. calcium fast bubbling magnesium very slow bubbling metal A no reaction copper no reaction Fig. 8.1 (a) (i) State and explain one variable which the student must keep the same if her assessment of the relative reactivity of the four metals is to be reliable. variable explanation [3] (ii) The student found that the pH of the mixture produced when calcium reacted was 12. State the name or formula of the ion whose concentration has increased and which is responsible for the change in pH. Explain your answer briefly. ion explanation [2]

19 © UCLES 2011 0653/32/M/J/11 [Turn over For Examiner's Use (iii) The student then carried out a second experiment to compare the reactivity of unknown metal A with that of copper. For her experiment she used a piece of metal A and a solution of the salt, copper nitrate, contained in a beaker. Outline how the student could use these materials to find out which metal, A or copper, is the more reactive. [2] (b) If a lighted wooden splint is held in the mouth of the test-tube in which calcium is reacting with water, the hydrogen given off burns with a small explosive pop. The explosive pop is caused by the rapid oxidation of hydrogen gas, H2. pop splint Suggest the balanced symbolic equation for the oxidation of hydrogen. [2]

20 © UCLES 2011 0653/32/M/J/11 For Examiner's Use 9 (a) Name the part of a flower that carries out each of the following functions. (i) attracts insects to the flower [1] (ii) makes pollen [1] (b) Complete the table to describe the differences between the stigmas of insect-pollinated and wind-pollinated flowers. feature insect-pollinated flower wind-pollinated flower shape of stigma position of stigma [2] (c) The cells in the petals of most flowers do not contain chlorophyll and cannot photosynthesise. (i) Describe how the cells in flowers obtain sugars and other nutrients. [2] (ii) Suggest one reason why the cells in flowers need sugars. [1]

21 © UCLES 2011 0653/32/M/J/11 [Turn over For Examiner's Use 10 (a) Fig. 10.1 shows a room heated by a convector heater, placed in the middle of the floor. heater A B C D E Fig. 10.1 (i) On Fig. 10.1 draw the convection currents of air produced by the heater. Use arrows to show their direction. [1] (ii) State which labelled part of the room will be the coldest, hottest. Explain your answers. [3]

22 © UCLES 2011 0653/32/M/J/11 For Examiner's Use (b) Fig. 10.2 shows the structure of the walls of a house in a cold climate. Heat can escape through the walls of the house. inside house outside house concrete block concrete block aluminium foil expanded polystyrene with trapped gas Fig. 10.2 Explain how the structure of the wall in Fig. 10.2 reduces heat loss. [3]

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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/M/J/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 May/June 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 May/June 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 – May/June 2011 0653 32 © University of Cambridge International Examinations 2011 1 (a) (i) population ; [1] (ii) community ; [1] (iii) consumer ; [1] (b) (i) more oxygen can be absorbed from the air / in the lungs ; more oxygen is carried / supplied to cells / muscles ; for respiration / to release energy ; [max 2] (ii) ref. to temperature regulation / homeostasis ; insulation / reduces heat loss from the body ; prevents body temperature dropping too low ; [max 2] (c) (i) agriculture ; mining ; building (roads, houses) ; tourism / ski resorts / ovp ; [max 2] (ii) ref. to species diversity ; idea of their importance in food chain / provide food for pumas / so pumas won't become extinct ; other, e.g. tourism / moral arguments ; [max 2] [Total: 11] 2 (a) (i) mirror in correct position and at correct angle ; [1] (ii) straight lines from torch to mirror to observer with approx correct angle of incidence and reflection ; [1] (b) (i) lamp / bulb and cell and switch ; [1] (ii) correct symbols linked together in series ; [1] (c) wider base ; centre of mass lower ; [2] [Total: 6]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2011 0653 32 © University of Cambridge International Examinations 2011 3 (a) lithium is (very) reactive / easily combines / reacts with other elements / substances ; oil prevents oxidation / reaction with air / oxygen / water / oil forms a protective barrier ; [2] (b) (i) mix acid and carbonate (in beaker) ; ensure carbonate in excess ; details of how to ensure carbonate in excess ; filter mixture ; [max 3] (ii) lithium carbonate + hydrochloric acid → lithium chloride + carbon dioxide + water ; [1] (c) (i) ions must be able to move / liquid must be able to conduct electricity ; ions not free in solid ; extra detail e.g. so that positive ions can move to cathode ; [max 2] (ii) each ion gains one electron / electron configuration changes from 2 to 2.1 ; [1] [Total: 9] 4 (a) beta / gamma are too penetrating ; beta / gamma can pass through smoke ; current would never flow (between electrodes) / beta / gamma not ionising (enough) ; beta / gamma would be a hazard to people ; [2] (b) (i) working ; 450 – 480 years ; [2] (ii) has a very long half-life ; [1] [Total: 5]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2011 0653 32 © University of Cambridge International Examinations 2011 5 (a) reference to: timescale / time to renew ; action of heat / pressure ; action of microorganisms ; [max 2] (b) 6 × 12 (72) + 14 × 1 ; [1] (c) (i) X drawn on bond in methane ; [1] (ii) exothermic means heat / energy / released ; more energy released when bonds form than is absorbed when bonds break ; [2] (d) (i) incomplete combustion of the fuel ; [1] (ii) nitrogen is in the air (intake) ; (most) nitrogen does not react / nitrogen is unreactive ; [2] [Total: 9] 6 (a) cell tissue organ sperm eye stomach heart ;; (1 mark for any two correct) [2] (b) ref. to enzymes ; work more slowly at lower temperatures ; denatured at higher temperatures ; [max 2] (c) (i) steady / linear / proportional, increase ; from 0.6 to 1.1 (g / cm2) / by 0.5 (g / cm2) ; [max 2] (ii) these foods contain calcium / calcium needed for bones ; older children need more calcium / ref. to increasing mineral content of bones ; [2] (iii) any citrus fruit / blackcurrants / other valid examples ; [1] [Total: 9]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2011 0653 32 © University of Cambridge International Examinations 2011 7 (a) (i) gravity / weight ; [1] (ii) air resistance increases ; upward force greater than downward force ; produces deceleration / upwards acceleration ; [3] (b) (i) around 88 s ; [1] (ii) on any horizontal section ; [1] (iii) distance = area under graph (or numbers) ; = 10 × 20 = 200 m ; [2] [Total: 8] 8 (a) (i) temperature / surface area of metal ; temperature / surface area affects the rate ; explanation of effect in terms of particles ; idea of isolating the effect of changing one variable ; [max 3] (ii) hydroxide / OH– ; solution is alkaline / water + metal produces alkali ; [2] (iii) place metal into the copper nitrate solution ; if copper forms / is displaced then metal A is more reactive than copper ; if there is no reaction, copper is the more reactive ; [max 2] (b) 2H2 + O2 → 2H2O ;; (formulae and balanced – allow 1 mark for H2 + O → H2O) [2] [Total: 9]

Page 6 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2011 0653 32 © University of Cambridge International Examinations 2011 9 (a) (i) petals / nectary / nectar / corolla ; [1] (ii) anther / stamen ; [1] (b) feature insect-pollinated flower wind-pollinated flower shape of stigma rounded / flat / smooth feathery ; position of stigma inside flower / inside petals dangling / outside flower / outside petals ; (one mark for each two correct) [2] (c) (i) (sugars produced by) photosynthesis in leaves ; transported (to flowers) in phloem ; as sucrose ; [max 2] (ii) for respiration / for energy / to make nectar / named energy-requiring process ; [1] [Total: 7] 10 (a) (i) lines go up in the middle and down round the side and arrows in correct direction ; [1] (ii) coldest: A, hottest: C ; hot air rises, cold air sinks ; hot air rises because its less dense than cold air (vice versa) ; [3] (b) air / gas / expanded polystyrene is a poor conductor of heat / good insulator ; concrete block is a poor conductor of heat / good insulator ; trapped gas / air cannot carry heat around by convection ; aluminium reflects heat back into house ; [max 3] [Total: 7]