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

This document consists of 21 printed pages and 3 blank pages. IB11 11_0653_22/3RP © UCLES 2011 [Turn over *2674589816* 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 0653/22 Paper 2 (Core) 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 0653/22/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 used 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) State the chemical formula of hydrochloric acid. [1] (iii) After some time, the student observed that the gas stopped forming, but a small piece of the rock sample remained in the large side-arm tube. Explain why gas stopped forming. [2] (iv) The student carried out a flame test on the solution that remained in the large side- arm tube. This test produced an orange-red colour. Name the element that this observation suggests is contained in the rock sample. [1]

3 © UCLES 2011 0653/22/O/N/11 [Turn over For Examiner's Use (b) In recent years, the amount of carbon dioxide dissolving in seawater has increased. During this period, many coral reefs have become weakened and damaged. (i) State and explain briefly how an increase in carbon dioxide concentration will affect the pH of seawater. [2] (ii) Suggest a reason why an increase in carbon dioxide concentration might be responsible for damage to coral reefs. [1]

4 © UCLES 2011 0653/22/O/N/11 For Examiner's Use 2 (a) Fig. 2.1 shows the horizontal forces acting on an aircraft moving along the runway. These forces are balanced. … Fig. 2.1 (i) The arrow to the right represents the driving force produced by the engines. On the diagram, name the other force. [1] (ii) Explain what is meant by the phrase forces are balanced. [1] (iii) Describe the movement of the aircraft when these forces are balanced. [1] (b) In the air, the aircraft travels at 80 m / s for one hour. Calculate the distance travelled. State the formula that you use and show your working. formula used working m [2]

5 © UCLES 2011 0653/22/O/N/11 [Turn over For Examiner's Use (c) People who fly frequently have greater exposure to ionising radiation than those who do not fly. (i) Explain why exposure to ionising radiation may be harmful. [2] (ii) This ionising radiation is cosmic radiation from outer space. This is one source of background radiation. State one other natural source of background radiation. [1] (d) The aircraft is able to navigate using radar. This involves using microwaves. These are part of the electromagnetic spectrum. Name one other wave which is part of the electromagnetic spectrum and give a use for this radiation. name use [2]

6 © UCLES 2011 0653/22/O/N/11 For Examiner's Use 3 (a) Complete the word equation for aerobic respiration. oxygen + + [2] (b) Describe how oxygen is transported from the lungs to a cell in a human muscle. [2] (c) An athlete ran on a treadmill at a slow speed for 5 minutes. She then ran on the same treadmill at a faster speed for 5 minutes. Fig. 3.1 shows the volume of oxygen she used per minute during both runs. 3.0 2.0 1.0 0 0 1 2 3 4 5 running fast running slowly volume of oxygen per minute / dm3 running time / minutes Fig. 3.1 (i) State the volume of oxygen used per minute by the athlete before she began to run. dm3 [1] (ii) Describe how the volume of oxygen used per minute during the fast run differs from the slow run. [2]

7 © UCLES 2011 0653/22/O/N/11 [Turn over For Examiner's Use (iii) Suggest an explanation for the differences you have described in (ii). [2] (d) Professional athletes do not smoke cigarettes because smoking can cause emphysema. This reduces the ability of oxygen to diffuse into the blood from the lungs. Explain what is meant by emphysema. [1]

8 © UCLES 2011 0653/22/O/N/11 For Examiner's Use 4 Fig. 4.1 shows an electric hairdryer. switch 1 switch 2 Fig. 4.1 (a) Fig. 4.2 shows the circuit diagram for the hairdryer. mains power supply M heater motor switch 1 switch 2 Fig. 4.2 (i) State which of the switches must be closed (on) for the heater in the hairdryer to work. [1]

9 © UCLES 2011 0653/22/O/N/11 [Turn over For Examiner's Use (ii) A student wanted to determine the resistance of the heater. Fig. 4.3 shows the circuit he built to measure the current passing through the heater and the potential difference across the heater. A V Fig. 4.3 His experiment did not work because his circuit was incorrect. Draw the correct circuit in the space below. [2] (b) The electricity used in the hairdryer was generated at a power station. (i) Name a fossil fuel that can be used in power stations. [1] (ii) Power is transmitted from the power station over large distances. A high voltage is always used. Explain why. [1]

10 © UCLES 2011 0653/22/O/N/11 For Examiner's Use The high voltage is produced by a transformer. Fig. 4.4 shows a simple transformer. primary coil secondary coil 5000 V 10 000 turns 400 000 V Fig. 4.4 (iii) Use the equation Vp/Vs = Np/Ns to calculate the number of turns in the secondary coil. Show your working. number of turns = [1] (iv) Transformers are also used between power lines and people’s houses. Explain why. [2]

11 © UCLES 2011 0653/22/O/N/11 [Turn over For Examiner's Use 5 Fig. 5.1 shows a section through a flower. petal filament sepal anther stigma ovary wall ovule Fig. 5.1 (a) (i) State the function of each of the following parts of the flower. petal anther [2] (ii) Name the part of the flower that develops into a seed, develops into a fruit. [2] (b) Flowers are involved in sexual reproduction. Complete the table to show whether each statement is true for asexual reproduction, sexual reproduction, both or neither. Use a tick (✓) for a correct statement and a cross () for an incorrect statement. You must write either a tick or cross in each space in the table. The first statement has been completed for you. statement asexual reproduction sexual reproduction gametes are involved  ✓ new individuals are produced a zygote is produced offspring are always genetically identical [3]

12 © UCLES 2011 0653/22/O/N/11 For Examiner's Use 6 Nordic gold is an alloy of four metals used to make coins. Table 6.1 shows information about the metals contained in Nordic gold. Table 6.1 metal % by mass in Nordic gold compound from which the metal is extracted aluminium 5 Al2O3 copper CuFeS2 tin 1 SnO2 zinc 5 ZnS (a) (i) Complete Table 6.1 by stating the percentage of copper in Nordic gold. [1] (ii) Suggest how Nordic gold could be made. [1] (iii) 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 6.1 which is not present in Nordic gold. [1] (iv) Suggest two properties of Nordic gold, other than its appearance, that make it a suitable material from which to make coins. 1 2 [2] (b) (i) Tin may be extracted from tin oxide by heating a mixture of tin oxide and carbon. The other product of this reaction is carbon monoxide. Write a word chemical equation for this reaction. [1]

13 © UCLES 2011 0653/22/O/N/11 [Turn over For Examiner's Use (ii) State and explain which substance is oxidised when tin is extracted from tin oxide. substance which is oxidised explanation [2] (c) (i) Aluminium is extracted from the ionic compound aluminium oxide by electrolysis. Explain the meanings of the following terms that are important in electrolysis. cathode electrolyte [3] (ii) State how the position of aluminium in the Periodic Table shows that aluminium atoms have three electrons in their outer shell. [1]

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15 © UCLES 2011 0653/22/O/N/11 [Turn over For Examiner's Use 7 (a) Fig. 7.1 shows a mother pushing her child in a baby buggy. She uses a force of 100 N. Fig. 7.1 The baby buggy is pushed 2000 m. Calculate how much work has been done. State the formula that you use and show your working. formula used working J [2]

16 © UCLES 2011 0653/22/O/N/11 For Examiner's Use (b) A child is playing on a swing. This is shown in Fig. 7.2. At the top of the oscillation, the child and swing are momentarily at rest. Fig. 7.2 (i) Write the correct energy type in the space to complete the box. gravitational potential energy at the top of the oscillation gravitational potential energy at the bottom of the oscillation … energy at the bottom of the oscillation energy losses + + = [1] (ii) Suggest a form of energy which is lost from the system. [1] (iii) Suggest where the lost energy goes. [1] (c) The child weighs 400 N. The Earth’s gravitational field strength is 10 N / kg. (i) State the mass of the child. kg [2]

17 © UCLES 2011 0653/22/O/N/11 [Turn over For Examiner's Use (ii) The average density of the human body is 1020 kg / m3. Calculate the volume of the child. State the formula that you use and show your working. formula used working m3 [1]

18 © UCLES 2011 0653/22/O/N/11 For Examiner's Use 8 Fig. 8.1 shows a tree frog that lives in a tropical rain forest. Fig. 8.1 (a) Tree frogs feed on insects. Enzymes in their alimentary canal break down large molecules in the insects into small ones. (i) State the correct biological term for this process. [1] (ii) Explain why this process is necessary for the frog's survival. [1] (iii) Use words from the list to complete the sentences about enzymes. carbohydrates cells denatured dissolved hydrogen killed oxygen proteins Enzymes are that catalyse chemical reactions in living organisms. One example of an enzyme is catalase, which breaks down hydrogen peroxide to water and . Enzymes are by high temperatures. [3] (b) Tropical rain forests have a high species diversity. (i) Explain what is meant by species diversity. [1]

19 © UCLES 2011 0653/22/O/N/11 [Turn over For Examiner's Use (ii) Many species of tree frog have become extinct in the last ten years. Suggest how the loss of tree frogs from the rain forest could damage the ecosystem. [2]

20 © UCLES 2011 0653/22/O/N/11 For Examiner's Use 9 Hydrocarbons are compounds which contain only the elements hydrogen and carbon. (a) The simplest hydrocarbon is methane, which is an important fuel. (i) State one natural source of methane. [1] (ii) Complete the displayed (graphical) formula of a methane molecule. H C [2] (iii) Carbon dioxide and carbon monoxide are compounds released into the atmosphere when methane burns. Describe one environmental disadvantage of each compound. carbon dioxide carbon monoxide [3]

21 © UCLES 2011 0653/22/O/N/11 For Examiner's Use (b) Table 9.1 shows the molecular formulae and boiling points of four hydrocarbons. Table 9.1 molecular formula boiling point / °C C6H14 69 C10H22 174 C12H26 216 C5H12 36 (i) Name a process which could be used to separate a mixture of the compounds in Table 9.1. [1] (ii) Use the information in Table 9.1 to describe how the boiling point of a hydrocarbon is affected by the mass of its molecules. [2]

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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 0653/22/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 0653/22 Paper 2 (Core 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 22 © University of Cambridge International Examinations 2011 1 (a) (i) carbon dioxide ; [1] (ii) HCl ; [1] (iii) reaction has stopped ; acid has been used up / owtte ; [2] (iv) calcium ; [1] (b) (i) carbon dioxide reacts with (sea)water ; makes water more acidic / less alkaline / pH decreases ; non-metal oxides are acidic ; [max 2] (ii) accept any reasonable science based idea: e.g. calcium carbonate may react with more acidic water / lower pH makes it more difficult for coral to extract ions from sea / coral organism does not survive in more acidic water / enzymes (in coral) denatured / ref. to global warming ; [max 1] [Total: 8] 2 (a) (i) air resistance / friction / drag ; [1] (ii) equal and opposite / cancel each other out ; [1] (iii) constant speed ; (allow constant velocity) [1] (b) distance = speed × time ; = 80 × 3600 = 288 000 m ; [2] (c) (i) mutations / damage DNA ; cause cancer ; kills cells ; radiation burns ; radiation sickness ; [max 2] (ii) (granite) rocks ; [1] (d) name ; appropriate use ; [2] [Total: 10]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 22 © University of Cambridge International Examinations 2011 3 (a) glucose ; water + carbon dioxide ; [2] (b) in the blood / in an artery / in a capillary ; ref. to haemoglobin ; in red blood cells ; [max 2] (c) (i) 0.4 dm3 ; [1] (ii) (assume answer refers to fast run unless otherwise stated) more (oxygen used per minute) ; increases more rapidly ; 0.9 dm3 more ; [max 2] (iii) more energy used when running faster ; muscles working harder ; therefore more respiration ; [max 2] (d) breakdown of walls of alveoli / reduction of surface area ; [1] [Total: 10] 4 (a) (i) switches 1 and 2 / both ; [1] (ii) voltmeter in parallel and ammeter in series ; everything else unchanged ; [2] (b) (i) coal / oil / gas ; [1] (ii) to reduce energy losses ; [1] (iii) (5000 / 400 000 = 10 000 / Ns, so Ns =) 800 000 (turns) ; [1] (iv) voltage needs to be lower ; for safety ; [2] [Total: 8]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 22 © University of Cambridge International Examinations 2011 5 (a) (i) attract insects ; produce, pollen / male gametes / male sex cells ; [2] (ii) ovule ; ovary ; [2] (b) statement asexual reproduction sexual reproduction gametes are involved
 new individuals are produced   a zygote is produced
 offspring are genetically identical 
one mark for each correct row (do not allow for anything where it is not clear whether it is a tick or a cross) [3] [Total: 7] 6 (a) (i) 89 (%) ; [1] (ii) metals are melted together ; [1] (iii) iron ; [1] (iv) unreactive ; strong / hard / not easily bent or deformed ; malleable ; [max 2] (b) (i) tin oxide + carbon → tin + carbon monoxide ; [1] (ii) carbon ; gains / bonds with oxygen ; [2] (c) (i) negative electrode ; compound in liquid form / solution / molten ; which conducts a current / contains free ions ; [3] (ii) group number = outer electrons / Al is in Group 3 ; [1] [Total: 12]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 22 © University of Cambridge International Examinations 2011 7 (a) work = force × distance ; = 100 × 2000 = 200 000 J ; [2] (b) (i) kinetic / movement ; [1] (ii) heat / sound ; [1] (iii) surroundings ; [1] (c) (i) 40 kg ; [1] (ii) volume = mass / density ; = 40 / 1020 = 0.04 m3 ; [2] [Total: 8] 8 (a) (i) digestion ; [1] (ii) so, nutrients / molecules, can be absorbed ; [1] (iii) proteins ; oxygen ; denatured ; [3] (b) (i) the number of different, species / types of organisms ; [1] (ii) affect, food chains / food webs ; predators of frogs may reduce in numbers ; insects / prey of frogs, may increase in numbers ; [max 2] [Total: 8]

Page 6 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 22 © University of Cambridge International Examinations 2011 9 (a) (i) formed as fossil fuel / decay of organic matter / digestive system of ruminants / vulcanism ; [1] (ii) H only other symbol ; H × 4 bonded to central C with all single bonds ; [2] (iii) (carbon dioxide) global warming / (runaway) greenhouse effect ; detail of mechanism e.g. reflects heat back to Earth ; causing climate change / or example of ; [max 2] (carbon monoxide) toxic (to humans) ; [max 1] (b) (i) fractional distillation / fractionation ; [1] (ii) the greater the molecular mass ; the higher the boiling point ; use of the data e.g. C12H26 most massive and has highest boiling point ; [max 2] [Total: 9]