Cambridge IGCSE Science - Combined 0653 — 2010 Oct/Nov Paper 2 · Variant 1

This document consists of 20 printed pages. IB10 11_0653_21/4RP © UCLES 2010 [Turn over *1144188971* 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 0653/21 Paper 2 (Core) October/November 2010 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 2010 0653/21/O/N/10 For Examiner's Use 1 (a) State the word equation for photosynthesis. + + [2] (b) (i) Name the green pigment found in plant leaves which absorbs energy from sunlight. [1] (ii) Fig. 1.1 is a diagram of a plant cell. On the diagram, draw a label line to where this green pigment would be found, and label it P. Fig. 1.1 [1]

3 © UCLES 2010 0653/21/O/N/10 [Turn over For Examiner's Use (c) A student fixed a piece of black paper over a leaf, which was still attached to the plant. He left the plant in the sun for two days. He then removed the leaf from the plant and tested it for starch, after removing the paper. (i) Using the letters given, list the correct sequence of the steps he took. A Add iodine solution to the leaf. B Place the leaf in boiling water. C Dip the leaf into water to soften it. D Place the leaf in hot ethanol. E Spread the leaf on a white tile. [3] (ii) Fig. 1.2 shows the leaf before and after he did the starch test. before testing after testing black paper Fig. 1.2 Iodine solution is orange-brown. It turns blue-black when it is in contact with starch. Complete the diagram of the leaf after testing in Fig. 1.2. Do not colour the diagram. Use labels to show which parts would look orange-brown and which parts would look blue-black. [2]

4 © UCLES 2010 0653/21/O/N/10 For Examiner's Use 2 Fig. 2.1 shows the apparatus a student used to measure the rate of reaction between some powdered metal and dilute hydrochloric acid. test-tube full of water water dilute hydrochloric acid conical flask 1.0 g powdered metal Fig. 2.1 When the student tilted the conical flask, the acid mixed with the powdered metal. If a reaction occurred, any gas which was produced bubbled up into the test-tube, pushing the water out. The student timed how long it took for the test-tube to fill with gas. (a) Describe how the student could test the gas to show that it was hydrogen. [2] (b) The student used the apparatus in Fig. 2.1 to compare the rates of reaction between dilute hydrochloric acid and three powdered metals, X, Y and Z. The results the student obtained are shown in Table 2.1. Table 2.1 metal mass of metal / g time for gas to fill the test-tube / seconds X 1.0 150 Y 1.0 45 Z 1.0 no gas was produced (i) One of the metals used was copper. State and explain which metal, X, Y or Z, was copper. metal explanation [2]

5 © UCLES 2010 0653/21/O/N/10 [Turn over For Examiner's Use (ii) Suggest two ways, other than using a catalyst, in which the student could increase the rate of reaction between metal X and dilute hydrochloric acid. 1 2 [2] (c) Fig. 2.2 shows another experiment in which the student added zinc carbonate to dilute sulfuric acid. A gas was given off and, when the bubbling stopped, some solid zinc carbonate remained in the mixture. dilute sulfuric acid solid zinc carbonate remaining zinc carbonate Fig. 2.2 (i) State the chemical formula of sulfuric acid. [1] (ii) Explain why the reaction eventually stopped even though some zinc carbonate powder remained. [1]

6 © UCLES 2010 0653/21/O/N/10 For Examiner's Use 3 Fig. 3.1 shows a rock that is falling from the top of a cliff into the river below. cliff river falling rock Fig. 3.1 (a) (i) As the rock falls, it gains kinetic energy. Name the form of energy the rock had at the top of the cliff. [1] (ii) Suggest what happens to the kinetic energy of the rock when the rock hits the water. [2] (b) Fig. 3.2 shows a speed-time graph for the motion of the rock. 25 20 15 10 5 0 0 1 2 3 4 5 6 7 time / s speed m / s Fig. 3.2 (i) After how many seconds was the speed of the rock 15 m / s? s [1]

7 © UCLES 2010 0653/21/O/N/10 [Turn over For Examiner's Use (ii) The rock is accelerating. Explain the meaning of the term accelerating. [1] (c) The rock contains radioactive substances emitting high levels of ionising radiation. (i) State how the radioactivity could be detected. [1] (ii) Explain why it would be dangerous for a person to handle this rock without proper protection. [1]

8 © UCLES 2010 0653/21/O/N/10 For Examiner's Use 4 Copper metal reacts with oxygen gas to form the black solid, copper oxide. (a) (i) Use this example to describe one difference between elements and compounds. [2] (ii) State why this reaction is an example of oxidation. [1] (iii) Name the type of chemical bonding found in copper oxide. [1] (b) Fig. 4.1 shows apparatus used in the electrolysis of copper chloride solution. power supply – + Fig. 4.1 (i) On the diagram, clearly label the anode and the electrolyte. [2] (ii) Copper chloride solution contains copper ions and chloride ions in water. State briefly two differences between a chlorine atom and a chloride ion. [2]

9 © UCLES 2010 0653/21/O/N/10 [Turn over For Examiner's Use (iii) Copper is a pink/orange metal and chlorine is a gas. Describe what would be observed at the positive and negative electrodes during electrolysis of copper chloride solution. observation at positive electrode observation at negative electrode [2]

10 © UCLES 2010 0653/21/O/N/10 For Examiner's Use 5 (a) Fig. 5.1 shows some of the different types of radiation in the electromagnetic spectrum. visible light infra- red radio waves ultra- violet gamma Fig. 5.1 Write the names of the missing types of radiation in the two empty spaces. [2] (b) Fig. 5.2 shows a ray of light hitting a mirror. air mirror 50° Fig. 5.2 (i) On Fig. 5.2, label the normal. [1] (ii) On Fig. 5.2, draw the reflected ray. [1] (iii) State the value of the angle of reflection. ° [1] (c) A sound wave has a frequency of 500 Hz. (i) Explain the meaning of the term frequency. [1] (ii) State the approximate range of audible frequencies detected by the normal human ear. [1]

11 © UCLES 2010 0653/21/O/N/10 [Turn over For Examiner's Use (d) Fig. 5.3 shows the wave traces made by four sounds. trace A trace B trace C trace D Fig. 5.3 (i) Which trace shows the sound wave with the lowest pitch? [1] (ii) Which trace shows the sound wave with the smallest amplitude? [1]

12 © UCLES 2010 0653/21/O/N/10 For Examiner's Use 6 (a) Complete the sentences about the human nervous system, using some of the words in the list. biceps brain detectors effectors nerves receptors Specialised cells in the human nervous system detect external stimuli. These cells are called . They convert the stimulus into electrical impulses in , which carry the impulse to the central nervous system. The central nervous system then sends impulses to parts of the body that respond to the stimulus, such as muscles or glands. These parts are called . [3] (b) When we smell food, the salivary glands respond by secreting saliva. Saliva contains the enzyme amylase, which breaks down large starch molecules to smaller sugar molecules. (i) Explain what is meant by the term enzyme. [2] (ii) Name the process by which large molecules are broken down to small ones in the alimentary canal. [1] (iii) Explain why this process is necessary. [2]

13 © UCLES 2010 0653/21/O/N/10 [Turn over For Examiner's Use 7 (a) Complete Table 7.1 to show the correct symbols of these electrical components. One symbol has been drawn for you. Table 7.1 component electrical symbol lamp ammeter fixed resistor [2] (b) A student set up the electric circuit in Fig. 7.1. It contained three lamps L1, L2 and L3. It contained three switches S1, S2 and S3. S1 S2 S3 L1 L2 L3 Fig. 7.1 In Table 7.2, write the words ‘on’ or ‘off’ to show when each lamp is lit or not lit for each set of switch positions. Table 7.2 switch position lamp ‘on’ or ‘off’ S1 S2 S3 L1 L2 L3 closed closed closed closed closed open closed open open [3]

14 © UCLES 2010 0653/21/O/N/10 For Examiner's Use (c) The student then set up another electric circuit shown in Fig. 7.2. lamp A lamp B Fig. 7.2 She noticed that neither lamp A nor lamp B lit up. She found nothing wrong with lamp A but the filament in lamp B was broken. (i) Explain why lamp A did not light up. [1] (ii) She replaced lamp B with a new lamp C. The resistance of both lamp A and lamp C was 5 ohms when lit. Calculate the combined resistance of both lamps in the working circuit. State the formula that you use and show your working. formula used working ohms [2]

15 © UCLES 2010 0653/21/O/N/10 [Turn over For Examiner's Use (d) Fig. 7.3 shows an electrical device. primary coil 20 turns 23 V a.c. secondary coil 200 turns Fig. 7.3 (i) Name the device. [1] (ii) Calculate the output voltage. Use the formula Vp / Vs = Np / Ns. Show your working. V [1]

16 © UCLES 2010 0653/21/O/N/10 For Examiner's Use 8 In jet engines, hydrocarbon molecules from the jet fuel mix with air and burn. This releases a large amount of energy and produces a mixture of waste gases. These waste gases pass out through the back of the jet engine into the atmosphere. jet engine air waste gases (a) Fig. 8.1 shows a molecule of octane, which is a typical hydrocarbon molecule in jet fuel. key carbon atom hydrogen atom octane Fig. 8.1 (i) State the chemical formula of octane. [1] (ii) Complete the word equation below for the complete combustion of octane. octane + + [2] (iii) Explain why the mixture of gases coming from the rear of the jet engine contains a large amount of nitrogen. [2] (iv) Explain why the metallic parts of the jet engine become hot when it is working. [1]

17 © UCLES 2010 0653/21/O/N/10 [Turn over For Examiner's Use (b) (i) A carbon atom has a proton (atomic) number 6 and a nucleon (mass) number 12. State the number of neutrons and electrons in this carbon atom. number of neutrons number of electrons [2] (ii) State the chemical symbol of another element which is in the same group in the Periodic Table as carbon. [1]

18 © UCLES 2010 0653/21/O/N/10 For Examiner's Use 9 The gray wolf is a predator that lives in North America. (a) The gray wolf’s diet consists mainly of white-tailed deer, beavers and snowshoe hares. These are all herbivores. They eat plants. (i) Construct a food web including all the organisms mentioned above. [3] (ii) State what the arrows in your food web represent. [1] (iii) Name the producers in the food web you have drawn. [1]

19 © UCLES 2010 0653/21/O/N/10 For Examiner's Use (b) Some of the chemicals in a gray wolf’s body contain carbon. When a wolf dies, its body is broken down by decomposers and the carbon is returned to the air. (i) Name one type of chemical in a wolf’s body that contains carbon. [1] (ii) Explain how the carbon from a wolf’s body is returned to the air after the wolf dies. [2] (c) Some gray wolves are born with darker fur than others. They can pass this fur colour to their offspring. If wolves live in cold places, they grow longer fur than wolves that live in warm places. They cannot pass their fur length to their offspring. Tick two boxes to show the cause of each of these types of variation in wolves’ fur. cause fur colour fur length genes only environment only genes and environment [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 2010 0653/21/O/N/10 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 2010 question paper for the guidance of teachers 0653 COMBINED SCIENCE 0653/21 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. • CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 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 2010 0653 21 © UCLES 2010 1 (a) carbon dioxide + water ; glucose / starch / sugar / carbohydrate + oxygen ; [2] (b) (i) chlorophyll ; [1] (ii) label to a chloroplast ; [1] (c) (i) B, D, C, E, A ; ; ; all five correct for 3 marks any four in correct sequence 2 marks any three in correct sequence 1 mark [3] (ii) area covered by paper shown on diagram ; orange-brown where paper was, blue-black elsewhere ; [2] [Total: 9] 2 (a) lighted splint / flame ; pops; [2] (b) (i) Z ; copper does not react with dilute acids / is not reactive enough / is unreactive ; [2] (ii) higher acid concentration ; higher (acid) temperature ; use more finely powdered metal ; ignore increase surface area of metal swirl / shake, (the mixture) ; [max 2] (c) (i) H2SO4 ; [1] (ii) acid used up / owtte ; [1] [Total: 8]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2010 0653 21 © UCLES 2010 3 (a) (i) (gravitational) potential energy ; [1] (ii) (KE) changed into ; sound / heat energy / KE of water ; [2] (b) (i) 2.3 s ± 0.1 s ; [1] (ii) speed is, increasing / changing / going faster ; [1] (c) (i) Geiger counter / Geiger-Müller tube / GM tube / photographic film / other valid answer ; [1] (ii) causes ionisation inside cells (not ‘ionise cells’) / damages cells / kills cells / mutation / damages DNA / radiation sickness / radiation burns / burns skin / cancer ; [1] [Total: 7] 4 (a) (i) copper / oxygen, is an element and copper oxide is a compound ; element contains one type of atom and compound contains two (or more) types of atom, bonded / joined / combined ; element found in Periodic Table and compound not ; [max 2] (ii) (definition) e.g. oxidation refers to reaction with / bonding with oxygen ; (context) e.g. oxygen has reacted/bonded with copper ; [max 1] (iii) ionic / electrovalent ; [1] (b) (i) anode and electrolyte clearly labelled ;; [2] (ii) ion is charged / negative but atom is uncharged / neutral ; ion has different numbers of electrons and protons but these numbers are the same in an atom ; ion has filled outer (electron) shell but atom, does not / has only 7 outer electrons ; [max 2] (iii) bubbles of gas / smell of chlorine / smell of swimming pools pink / orange layer / solid, forms ; [2] [Total: 10]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2010 0653 21 © UCLES 2010 5 (a) X-ray ; microwave ; (in correct place) [2] (b) (i) normal labelled ; [1] (ii) ray drawn at sensible angle ; [1] (iii) 50° ; [1] (c) (i) number of, waves / oscillations, per second / per unit time ; [1] (ii) 20 Hz – 20 000 Hz ; [1] (d) (i) trace D ; [1] (ii) trace A ; [1] [Total: 9] 6 (a) receptors ; nerves ; effectors ; [3] (b) (i) protein ; catalyst / definition of catalyst ; [2] (ii) digestion ; [1] (iii) so that the (small) molecules can be absorbed ; into the blood / through the gut wall ; so they can be used by cells ; [max 2] [Total: 8]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2010 0653 21 © UCLES 2010 7 (a) correct symbol for ammeter ; correct symbol for resistor ; [2] (b) Table 7.2 switch position lamp ‘on’ or ‘off’ S1 S2 S3 L1 L2 L3 closed closed closed on on on closed closed open on off on closed open open on off off (1 mark for each correct row) ;;; [3] (c) (i) broken circuit / incomplete circuit ; [1] (ii) R = R1 + R2 ; = 10 ohms ; [2] (d) (i) transformer ; [1] (ii) (Vs = 23 × 200 / 20 =) 230 (V) ; [1] [Total: 10] 8 (a) (i) C8H18 ; [1] (ii) (octane +) oxygen; → carbon dioxide + water; [LHS + RHS] [2] (iii) nitrogen, is in the air / enters with the air / owtte ; nitrogen, does not burn / react / change / is unreactive ; [2] (iv) heat comes from the burning fuel / combustion of the fuel is exothermic / there is an exothermic reaction (inside engine) / heat is conducted from where the fuel is burning ; [1] (b) (i) 6 ; 6 ; [2] (ii) Si / Ge / Sn / Pb ; [1] [Total: 9]

Page 6 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2010 0653 21 © UCLES 2010 9 (a) (i) white-tailed deer beavers gray wolf snowshoe hares plants all organisms at correct levels (allow if upside down) ; all organisms correctly connected ; all arrows shown in correct directions ; [3] (ii) energy (flow / transfer) ; [1] (iii) grass / other plants ; [1] (b) (i) protein / carbohydrate / glucose / fat ; allow any correct [1] (ii) (decomposers) respire ; release carbon dioxide ; [2] (c) cause fur colour fur length genes only
environment only
genes and environment [2] [Total: 10]