Cambridge IGCSE Science - Combined 0653 — 2013 May/June Paper 2 · Variant 1

This document consists of 23 printed pages and 1 blank page. IB13 06_0653_21/3RP © UCLES 2013 [Turn over *6016235304* UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/21 Paper 2 (Core) May/June 2013 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 pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units. 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 2013 0653/21/M/J/13 For Examiner's Use 1 (a) Table 1.1 shows the numbers of protons, neutrons and electrons in four atoms, A, B, C and D. Table 1.1 atom protons neutrons electrons A 1 0 1 B 8 8 8 C 1 1 1 D 15 16 15 (i) Name the central part of an atom that contains protons and neutrons. [1] (ii) Explain which one of the atoms, A, B, C or D, has a nucleon number (mass number) of 16. atom explanation [2] (iii) Use the information in Table 1.1 to explain why atoms do not have an overall electrical charge. [2]

3 © UCLES 2013 0653/21/M/J/13 [Turn over For Examiner's Use (b) Fig. 1.1 shows containers of hydrogen and helium. H2 He hydrogen molecule helium atom Fig. 1.1 (i) Hydrogen is usually described as a non-metal. Name the type of chemical bond joining the atoms in a hydrogen molecule. [1] (ii) Suggest why helium exists as uncombined atoms. [1] (c) Hydrogen is often included in the reactivity series of metals. Use the idea of reactivity to explain the observations shown in Fig. 1.2. dilute hydrochloric acid burning splint zinc pop Fig. 1.2 [2]

4 © UCLES 2013 0653/21/M/J/13 For Examiner's Use 2 (a) A fishing boat is floating on the sea. A fisherman drops a heavy anchor from the boat. The anchor accelerates as it falls through the water. (i) Name the downward force which makes the anchor accelerate. [1] (ii) Complete the sentence below to describe the main energy change that happens to the anchor during its fall. energy is changed into energy. [2] (b) Fig. 2.1 shows a diagram of a water wave. A B C D E D Fig. 2.1 Which measurement A, B, C, D or E is (i) the wavelength of the wave? [1] (ii) the amplitude of the wave? [1]

5 © UCLES 2013 0653/21/M/J/13 [Turn over For Examiner's Use (c) Water waves are a renewable energy resource. Fig. 2.2 shows how water waves can be used to produce electricity. waves water movement causes air to move in and out of the air chamber waves make water rise and fall in air chamber air chamber turbine generator Fig. 2.2 Complete the sentences below to describe how the kinetic energy of the waves is changed into electrical energy. The kinetic energy of the waves is transferred into the gravitational potential energy of the water. This causes the air to move and make the spin. Electrical energy is produced in the . [2]

6 © UCLES 2013 0653/21/M/J/13 For Examiner's Use 3 Fig. 3.1 shows some organisms that live in and around a pond. heron water snails yellow water lily fish fish not to scale Fig. 3.1 (a) Herons eat fish. Water snails eat water plants, such as yellow water lilies. Tick all the boxes that correctly describe each organism. producer consumer carnivore herbivore heron water snail yellow water lily [3] (b) The addition of a harmful substance to the environment is called pollution. Two examples of pollution caused by human activities are • untreated sewage entering a pond, • the release of methane into the atmosphere. (i) Explain why untreated sewage entering a pond may cause fish to die. [2]

7 © UCLES 2013 0653/21/M/J/13 [Turn over For Examiner's Use (ii) Methane is produced by bacteria and other decomposers breaking down organic waste material in rubbish dumps. Describe how air pollution by methane can harm the environment. [2]

8 © UCLES 2013 0653/21/M/J/13 For Examiner's Use 4 Petroleum (crude oil) and rock salt occur naturally in the Earth’s crust. (a) Petroleum is a mixture that contains thousands of different compounds. Many of these compounds are alkanes. (i) Complete the diagram of the alkane molecule that contains two carbon atoms. C H [2] (ii) Fig. 4.1 shows a simple pie chart of the composition of natural gas. other gases gas X Fig. 4.1 Name gas X. [1]

9 © UCLES 2013 0653/21/M/J/13 [Turn over For Examiner's Use (b) When petroleum is refined, it is separated into fractions. Fig. 4.2 shows a simplified diagram of apparatus that is used to refine petroleum. hot petroleum refinery gas diesel oil (gas oil) Fig. 4.2 (i) State the full name of the process shown in Fig. 4.2. [1] (ii) Refinery gas and diesel oil are used as fuels. Name the two compounds that are formed when alkanes in these fuels undergo complete combustion. and [2] (c) Rock salt contains mainly sodium chloride which is a compound of the alkali metal, sodium, and the halogen, chlorine. (i) Explain why the uncombined elements sodium and chlorine are not found in the Earth’s crust. [1]

10 © UCLES 2013 0653/21/M/J/13 For Examiner's Use (ii) Fig. 4.3 shows diagrams of a sodium atom and a chlorine atom. Na Cl Fig. 4.3 When sodium reacts with chlorine, the atoms shown in Fig. 4.3 first change into electrically charged atoms known as ions. Describe briefly what happens when sodium atoms and chlorine atoms are changed into ions. [2]

11 © UCLES 2013 0653/21/M/J/13 [Turn over For Examiner's Use 5 Milk is a liquid produced by cows and other mammals, on which they feed their young. Table 5.1 shows the mass of some of the substances in 100 g samples of milk from two mammals. Table 5.1 substance cow’s milk water-buffalo’s milk protein / g 3.2 4.5 fat / g 3.9 8.0 carbohydrate / g 4.8 4.9 calcium / mg 120 195 (a) Which substance shown in Table 5.1 is present in the samples of milk in the smallest quantity? [1] (b) Suggest which substance, not shown in Table 5.1, is present in the samples of milk in the largest quantity. [1] (c) Explain why both cow’s milk and water-buffalo’s milk produce a violet colour when tested with biuret solution. [1] (d) Predict the colour you would see if you added iodine solution to cow’s milk. Explain your answer. colour explanation [2] (e) List the components of milk, shown in Table 5.1, that provide energy. [1] (f) Explain one way in which drinking water-buffalo’s milk might be better for a person’s health than drinking cow’s milk. [2]

12 © UCLES 2013 0653/21/M/J/13 For Examiner's Use 6 (a) In a store, two workers are lifting 5 kg bags of flour onto the shelves. There are five shelves, 0.5 m apart. The lowest shelf is 0.5 m from the floor. Fig. 6.1 shows the two workers. 0.5 m 0.5 m 0.5 m 0.5 m 0.5 m shelf 5 shelf 4 shelf 3 shelf 2 shelf 1 worker Y worker X Fig. 6.1 (i) Worker X lifts a bag of flour onto shelf 2. Worker Y lifts a bag of flour onto shelf 4. Which worker has done more work? Explain your answer. worker because [1] (ii) State the unit in which work and energy are measured. [1] (iii) State the mass of each 5 kg bag of flour in grams. g [1] (iv) Each 5 kg bag of flour has a volume of 5500 cm3. Calculate the average density of the bag of flour. State your answer in g / cm3. State the formula that you use and show your working. formula working g / cm3 [2]

13 © UCLES 2013 0653/21/M/J/13 [Turn over For Examiner's Use (b) Three boys, A, B and C, walk together from their school to a store. They stay at the store for a few minutes and then return to school. When they leave the store, • one boy walks back to school at a steady pace, • one boy walks back to school at a slower steady pace, • one boy slows down gradually as he walks back to school. The graph in Fig. 6.2 shows how their speeds vary with time during the whole journey to the store and back again. 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 0 100 200 300 400 500 time / s speed / m per s 600 700 800 900 1000 boys boys A, , B and and C boy boy B boy boy A boy boy C boy A boy C boy B boys A, B and C Fig. 6.2 (i) Calculate the distance of the store from the school. Show your working. m [2] (ii) For how many seconds do the boys stay in the store? s [1] (iii) Which boy slowed down on his way back to school? State a reason for your answer. boy because [2]

14 © UCLES 2013 0653/21/M/J/13 For Examiner's Use 7 (a) Sodium hydrogencarbonate, NaHCO3, is a white solid compound. State the number of different elements that are shown combined in the formula, NaHCO3. [1] (b) Fig. 7.1 shows apparatus a student used to investigate the reaction between sodium hydrogencarbonate and dilute hydrochloric acid. side-arm test-tube dilute hydrochloric acid sodium hydrogencarbonate full range indicator solution (Universal Indicator) Fig. 7.1 The student observed that the indicator changed colour from green to orange. Explain this observation. [2]

15 © UCLES 2013 0653/21/M/J/13 [Turn over For Examiner's Use (c) The student investigated the temperature change when sodium hydrogencarbonate was added to excess dilute hydrochloric acid. Fig. 7.2 shows the apparatus she used. dilute hydrochloric acid sodium hydrogencarbonate thermometer Fig. 7.2 Table 7.1 shows the temperature measurements the student made. Table 7.1 temperature of the acid before the reaction / °C 19.0 temperature of the reaction mixture after reaction / °C 12.0 (i) Calculate the temperature change that occurred during the reaction. °C [2] (ii) State the term that is used to describe chemical reactions that cause this type of temperature change. [1] (d) A soluble calcium compound can be made by reacting lemon juice with finely powdered egg shells, which are made mainly of calcium carbonate. Lemon juice contains a relatively low concentration of acid. State the effect on the rate of reaction of using a relatively low acid concentration, using egg shells in the form of a fine powder. [2]

16 © UCLES 2013 0653/21/M/J/13 For Examiner's Use 8 Fig. 8.1 shows the human gas exchange system. A B Fig. 8.1 (a) Name structures A and B. A B [2] (b) Table 8.1 shows the differences in the composition of inspired and expired air. Table 8.1 gas percentage in inspired air percentage in expired air nitrogen 78 oxygen 21 17 carbon dioxide 0.04 4 noble gases 1 (i) Complete Table 8.1. [1] (ii) Name one noble gas that is present in air. [1]

17 © UCLES 2013 0653/21/M/J/13 [Turn over For Examiner's Use (iii) Explain why the air that we breathe out (expired air) contains less oxygen and more carbon dioxide than the air we breathe in. [2] (iv) Describe how you could show that expired air contains more carbon dioxide than inspired air. You can use a diagram if it helps your answer. [3]

18 © UCLES 2013 0653/21/M/J/13 For Examiner's Use (c) An athlete exercised on a treadmill. The treadmill measured her power output, in watts. The faster she ran, the greater her power output. (i) Explain why the athlete’s power output was greater when she ran faster. [2]

19 © UCLES 2013 0653/21/M/J/13 [Turn over For Examiner's Use (ii) The athlete was connected to a machine that measured the rate and depth of her breathing. Fig. 8.2 shows how her depth of breathing changed when she ran with different power outputs. 0 50 100 150 200 250 3 2 1 0 power output when running / W volume of air breathed in with each breath / dm3 Fig. 8.2 Describe how the athlete’s depth of breathing changed when she ran with a greater power output. [2] (iii) State one other way in which her breathing would change when she ran with a greater power output. [1]

20 © UCLES 2013 0653/21/M/J/13 For Examiner's Use 9 (a) Complete the following sentences choosing from the terms below. Each term may be used once, more than once or not at all. current parallel potential difference resistance series watt A flow of electric charge is called a . An ammeter is used to measure . [2]

21 © UCLES 2013 0653/21/M/J/13 [Turn over For Examiner's Use (b) A student investigated how a change in potential difference across a lamp affected the current flowing through the lamp. She used wires to connect the components shown in Fig. 9.1 to make a circuit. 1 2 3 0 V A + – + – 0.4 0.6 0.8 1.0 0.2 0 Fig. 9.1 Using the correct circuit symbols, draw a diagram to show the circuit she used. [4]

22 © UCLES 2013 0653/21/M/J/13 For Examiner's Use (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 the cables are hung loosely. [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 2013 0653/21/M/J/13 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

CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the May/June 2013 series 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 should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the May/June 2013 series for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level components and some Ordinary Level components. www.XtremePapers.com

Page 2 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0653 21 © Cambridge International Examinations 2013 1 (a) (i) nucleus; [1] (ii) B ; sum of protons and neutrons is 16 ; [2] (iii) numbers of protons and electrons are the same ; protons positive electrons negative ; charges (of protons and electrons) cancel ; [max 2] (b) (i) covalent ; [1] (ii) helium is inert / unreactive / no need to bond (to become stable) ; reference to complete outer shell ; [max 1] (c) pop (test) indicates hydrogen (given off) ; zinc displaces hydrogen / zinc reacts with hydrochloric acid to produce hydrogen ; zinc more reactive than hydrogen ; [max 2] [Total: 9] 2 (a) (i) gravity ; [1] (ii) gravitational / potential / gravitational potential ; kinetic ; [2] (b) (i) E ; [1] (ii) B ; [1] (c) turbine ; generator ; [2] [Total: 7]

Page 3 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0653 21 © Cambridge International Examinations 2013 3 (a) producer consumer carnivore herbivore heron × × water snail × × yellow water lily × 1 mark per correct row ;;; [3] (b) (i) eutrophication ; increased growth of algae ; reduction of (dissolved) oxygen ; reference to toxins / named toxin ; [max 2] (ii) reference to greenhouse gas ; traps heat ; global warming / climate change ; reference to consequence of global warming (e.g. sea level rise, more extremes of weather, change in habitats of living organisms) ; [max 2] [Total: 7] 4 (a) (i) chain of two carbon atoms joined by single bond ; only six hydrogen atoms correctly bonded to carbon ; [2] (ii) methane ; [1] (b) (i) fractional distillation / fractionation ; [1] (ii) carbon dioxide ; water (ignore vapour) ; [2] (c) (i) too reactive / compounds much more stable ; [1] (ii) electrons are transferred ; sodium atoms lose (one) electron / outer shell electron / become 2.8 / become positively charged ; chlorine atoms gain (one) electron / complete outer shell / become 2.8.8 / become negatively charged ; [max 2] [Total: 9]

Page 4 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0653 21 © Cambridge International Examinations 2013 5 (a) calcium ; [1] (b) water ; [1] (c) they contain protein ; [1] (d) orange / brown ; it does not contain starch / substances from animals do not contain starch / the only carbohydrate is sugar / lactose ; [2] (e) protein, fat and carbohydrate ; [1] (f) has more calcium ; for, teeth / bones ; OR has more protein ; for, growth / repair / other specific function of protein ; [max 2] [Total: 8] 6 (a) (i) worker Y (no mark) same force but bigger distance; work is force × distance and distance is bigger ; [max1] (ii) joules ; [1] (iii) 5000 (g) ; [1] (iv) density = mass/volume ; = 5000/5500 = 0.91 (g / cm3) ; [2] (b) (i) use of graph / working ; 288 (m) ; [2] (ii) 240 (s) ; [1] (iii) boy C ; line on graph goes down etc. (so speed was changing) ; [2] [Total: 10]

Page 5 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0653 21 © Cambridge International Examinations 2013 7 (a) 4 ; [1] (b) carbon dioxide ; produces an acid(ic solution) / lowers pH ; [2] (c) (i) decrease ; of 7 (°C) ; [2] ( –7 gains 2 marks) (ii) endothermic ; [1] (d) lowers reaction rate ; increases reaction rate ; [2] [Total: 8] 8 (a) A: trachea ; B: broncholi / bronchiole ; [2] (b) (i) gas percentage in inspired air percentage in expired air nitrogen 78 78 oxygen 21 17 carbon dioxide 0.04 4 noble gases 1 1 both for 1 mark; [1] (ii) argon / neon / xenon / krypton / radon ; [1] (iii) respiration ; uses oxygen and produces carbon dioxide ; oxygen diffuses into blood and carbon dioxide diffuses from the blood ; [max 2] (iv) limewater / hydrogencarbonate indicator ; method bubbles / mixes both types of air through the indicator ; reference to comparison of time taken for indicator to change colour ; [3]

Page 6 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0653 21 © Cambridge International Examinations 2013 (c) (i) reference to energy / work ; more energy used / more work done per unit time ; [2] (ii) increased ; use of comparative figures (e.g. 0.5 dm3 when no power output, 2.8 dm3 at 225 W) ; reference to change of gradient at 50 W ; [max 2] (iii) faster / more breaths per minute ; [1] [Total: 14] 9 (a) current ; current ; [2] (b) most / greater the two symbols correct ; all five symbols correct ; ammeter in series and voltmeter in parallel ; everything else correct ; [4] (c) metals expand when hot / contract when cold ; cables could snap / become too tight and damage pylons ; if put up tight in summer ; [max 2] [Total: 8]