Cambridge IGCSE Science - Combined 0653 — 2013 May/June Paper 3 · Variant 1

This document consists of 26 printed pages and 2 blank pages. IB13 06_0653_31/3RP © UCLES 2013 [Turn over *5634579269* UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/31 Paper 3 (Extended) 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 28. 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 0653/31/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 2 2 2 B 3 4 3 C 1 0 1 D 4 5 4 (i) Explain which one of the atoms, A, B, C or D, has a nucleon number (mass number) of four. atom explanation [1] (ii) Explain why all atoms do not have an overall electrical charge. [2]

3 © UCLES 2013 0653/31/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) Describe, in terms of electrons, how a chemical bond forms between two hydrogen atoms. You may draw a diagram of a hydrogen molecule if it helps you to answer this question. [2] (ii) Explain why helium exists as single atoms and not as molecules. [1]

4 © UCLES 2013 0653/31/M/J/13 For Examiner's Use (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 dilute hydrochloric acid silver no reaction Fig. 1.2 [3]

5 © UCLES 2013 0653/31/M/J/13 [Turn over For Examiner's Use 2 (a) A fishing boat uses echo sounding to detect a shoal of fish. This is shown in Fig. 2.1. shoal of fish Fig. 2.1 Short pulses of sound are sent out from the boat. The echo from the shoal of fish is detected by a receiver on the boat 0.2 seconds later. Sound waves travel through water at a speed of 1600 m / s. (i) Calculate the distance of the shoal of fish below the boat. State the formula that you use and show your working. formula working [2] (ii) The sound waves have a wavelength of 0.25 m. Calculate the frequency of the waves. State the formula that you use and show your working. formula working [2]

6 © UCLES 2013 0653/31/M/J/13 For Examiner's Use (b) (i) Water waves are a renewable energy resource. Outline two advantages of using renewable energy resources. 1 2 [2] (ii) 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 Using the information in Fig. 2.2, describe two of the energy transfers that are involved in changing the kinetic energy of the waves into electrical energy. [2]

7 © UCLES 2013 0653/31/M/J/13 [Turn over For Examiner's Use (c) Fig. 2.3 shows an iceberg floating in the sea. water vapour in air air sea water ice Fig. 2.3 (i) Which material named on Fig. 2.3 best fits the statement below? “The particles are able to move, are randomly arranged and are closely packed.” [1] (ii) Name the process by which water molecules in the sea become water molecules in the air. [1]

8 © UCLES 2013 0653/31/M/J/13 For Examiner's Use 3 The addition of a harmful substance to the environment is called pollution. Three examples of pollution caused by human activities are • acid rain, • fertilisers entering rivers and lakes, • the release of too much carbon dioxide into the atmosphere. (a) Describe how acid rain is caused. [2] (b) Explain what happens in a lake after large quantities of fertilisers are washed into it. [3] (c) Explain how cutting down forests can result in an increase in the carbon dioxide concentration in the atmosphere. [2]

9 © UCLES 2013 0653/31/M/J/13 [Turn over Please turn over for Question 4.

10 © UCLES 2013 0653/31/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. Draw the structure of the alkane molecule that contains eight hydrogen atoms. Use short lines to represent covalent bonds. [2] (b) When petroleum is refined, it is separated into simpler mixtures. Fig. 4.1 shows a simplified diagram of apparatus that is used to refine petroleum. hot petroleum A B C D Fig. 4.1 Explain, in terms of intermolecular forces and the size of molecules, why the average boiling point of the fraction at B differs from the average boiling point of the fraction at C. [3]

11 © UCLES 2013 0653/31/M/J/13 [Turn over For Examiner's Use (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] (ii) Describe the changes in electron configuration when sodium atoms (2,8,1) react with chlorine atoms (2,8,7) to form sodium chloride. [2]

12 © UCLES 2013 0653/31/M/J/13 For Examiner's Use 5 Milk is a liquid produced by cows, goats and other mammals, on which they feed their young. (a) Table 5.1 shows the mass of some of the substances in 100 g samples of milk from three mammals. Table 5.1 substance cow’s milk goat’s milk water-buffalo’s milk protein / g 3.2 3.1 4.5 fat / g 3.9 3.5 8.0 carbohydrate / g 4.8 4.4 4.9 calcium / mg 120 100 195 (i) Which substance shown in Table 5.1 is present in the samples of milk in the smallest quantity? [1] (ii) Suggest which substance, not shown in Table 5.1, is present in the samples of milk in the largest quantity. [1] (iii) Explain one way in which drinking water-buffalo’s milk might be better for a person's health than drinking goat’s milk. [2] (iv) State and explain which substance in Table 5.1 does not need to be digested in the human alimentary canal. [2]

13 © UCLES 2013 0653/31/M/J/13 [Turn over For Examiner's Use (b) Milk can be used for making yoghurt. • Bacteria are added to the milk. The milk is kept at a temperature of 40 °C. • The bacteria convert lactose in the milk to lactic acid. • When the pH has reached about 4.5, the yoghurt is moved to a refrigerator at a temperature of 3 °C. (i) Explain why the milk is kept at a temperature of 40 °C after the bacteria have been added to it. [2] (ii) Suggest why the yoghurt is kept in a refrigerator at a temperature of 3 °C. [1] (iii) Milk has a pH of about 6.5. Explain why the pH of milk changes during the manufacture of yoghurt. [1]

14 © UCLES 2013 0653/31/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, 0.4 m apart. The lowest shelf is 0.4 m from the floor. Fig. 6.1 shows the two workers. 0.4 m 0.4 m 0.4 m 0.4 m 0.4 m shelf 5 shelf 4 shelf 3 shelf 2 shelf 1 worker Y worker X Fig. 6.1 (i) Worker X lifts three bags from the floor to shelf 2. Worker Y lifts one bag from the floor to shelf 5. Worker X says that he has done more work than worker Y. Use calculations of the work done to explain whether or not he is correct. State the formula that you use. formula [2] (ii) Each worker lifts one bag from the floor to shelf 2. Worker X does this more quickly than worker Y. Which worker exerted the higher power during their lift? Explain your answer. [1]

15 © UCLES 2013 0653/31/M/J/13 [Turn over For Examiner's Use (iii) 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]

16 © UCLES 2013 0653/31/M/J/13 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. [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 [1]

17 © UCLES 2013 0653/31/M/J/13 [Turn over For Examiner's Use 7 (a) Fig. 7.1 shows apparatus a student used to investigate the reaction between a white powder and dilute hydrochloric acid. The student predicted that a gas would be given off in her experiment and chose to test the gas using limewater. side-arm test-tube dilute hydrochloric acid white powder limewater Fig. 7.1 State the gas that the student predicted would be given off. Explain your answer. name of gas explanation [2]

18 © UCLES 2013 0653/31/M/J/13 For Examiner's Use (b) The student investigated the temperature change when sodium hydrogencarbonate was added to excess dilute hydrochloric acid. Fig. 7.2 shows the apparatus she used. temperature sensor insulated beaker reaction mixture Fig. 7.2 Temperature measurements were displayed on the computer screen as a graph of temperature against time. This graph is shown in Fig. 7.3. 0 1 2 3 4 time / min 5 6 7 8 20 15 10 5 0 temperature / °C start of start of experiment experiment start of experiment Fig. 7.3 (i) On the graph, mark with an X the point where sodium hydrogencarbonate was added to the dilute hydrochloric acid. [1]

19 © UCLES 2013 0653/31/M/J/13 [Turn over For Examiner's Use (ii) Calculate the temperature change shown in Fig. 7.3 that occurred during the reaction. [2] (iii) Use the results shown in Fig. 7.3 to explain, in terms of chemical energy and heat energy, the energy transformation that occurred during the reaction. [2] (c) Sodium hydrogencarbonate, NaHCO3, is a solid compound made of sodium ions and hydrogencarbonate ions. Sodium is a metal in Group 1 of the Periodic Table. Deduce the formula and electrical charge of a hydrogencarbonate ion. Explain your answer. [3]

20 © UCLES 2013 0653/31/M/J/13 For Examiner's Use 8 Fig. 8.1 shows the human gas exchange system. Fig. 8.1 (a) Use label lines to label each of these structures on Fig. 8.1. trachea bronchus [2] (b) Gas exchange takes place across the surface of the alveoli in the lungs. List two features of alveoli that help gas exchange to take place quickly. 1 2 [2]

21 © UCLES 2013 0653/31/M/J/13 [Turn over For Examiner's Use (c) The gas exchange system is protected from pathogens and harmful substances by a tissue, containing goblet cells and ciliated cells, that lines the nose, trachea and bronchi. Fig. 8.2 shows part of this tissue inside the nose. goblet cell (produces mucus) to opening of nostril to lungs thin layer of mucus cilia Fig. 8.2 Describe how the tissue shown in Fig. 8.2 helps to stop harmful substances getting into the lungs. [2]

22 © UCLES 2013 0653/31/M/J/13 For Examiner's Use (d) An experiment was carried out to find out how passive smoking affects the activity of the goblet cells and cilia. Six people sat in a closed room. On day 1, they breathed normal, clean air. On day 2, they breathed air containing cigarette smoke. After one hour, a substance was sprayed into each person’s nose. After 40 minutes, the researchers measured the percentage of the substance that remained in each person’s nose. This was done on both days. The faster the cilia and goblet cells were working, the faster the substance was removed from the nose. Table 8.1 shows the results. Table 8.1 percentage of substance remaining after 40 minutes person day 1 after breathing clean air day 2 after breathing air containing cigarette smoke 1 65 26 2 84 49 3 67 96 4 23 51 5 40 91 6 78 24 (ii) Which three persons’ results showed that breathing air containing cigarette smoke slowed down the rate at which their cilia and goblet cells worked? [1] (ii) Suggest how exposure to cigarette smoke could affect the health of these three people. [3]

23 © UCLES 2013 0653/31/M/J/13 [Turn over Please turn over for Question 9.

24 © UCLES 2013 0653/31/M/J/13 For Examiner's Use 9 (a) 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 (i) Using the correct circuit symbols, draw a diagram to show the circuit she used. [3]

25 © UCLES 2013 0653/31/M/J/13 For Examiner's Use (ii) The student measured the current passing through a wire when a potential difference was applied across it. Calculate the resistance of the wire when a potential difference of 0.3 V is applied and the current measured is 0.5 A. State the formula that you use and show your working. formula working [2] (b) 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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28 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 0653/31/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 0653/31 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 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 31 © Cambridge International Examinations 2013 1 (a) (i) (A) sum of protons and neutrons is four/nucleon number is sum of protons and neutrons; [1] (ii) numbers of protons and electrons are the same; protons positive electrons negative; charges (of protons and electrons) cancel; [max 2] (b) (i) atoms share electrons; electron pair (is shared); electron pair lies between nuclei/shields nuclear repulsion; [max 2] (ii) helium (atoms) inert/stable; reference to complete (outer) shell; [max 1] (c) pop (test) indicates hydrogen (given off); zinc displaces hydrogen/reacts with HCl to produce hydrogen; zinc more reactive than hydrogen; silver less reactive than hydrogen (so no reaction); [max 3] (allow max 1 if only response is zinc is more reactive than silver) [Total: 9] 2 (a) (i) distance = speed × time; = 1600 × 0.2/2 = 160 m; [2] (ii) (frequency =) velocity ÷ wavelength; frequency = 1600/0.25 = 6400 Hz; [2] (b) (i) idea that fossil fuels are conserved; no CO2/greenhouse gas emissions; ref. to global warming/reduced consequence of global warming described; no emissions causing acid rain; [max 2] (ii) transfer of KE to PE as water moves up chamber; transfer of KE to air inside chamber; transfer of KE of air to KE of (rotation of) turbine; transfer of KE of turbine to KE of generator; transfer of KE of generator to electrical energy; [max 2] (allow strong implication of these transfers) (c) (i) sea water; [1] (ii) evaporation; [1] [Total: 10]

Page 3 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0653 31 © Cambridge International Examinations 2013 3 (a) combustion/burning, of (fossil) fuels/coal; sulfur dioxide produced; (which) reacts with/dissolves in, water (in atmosphere); [max 2] (b) eutrophication; increased growth of algae; blocks light to plants deeper down; algae/plants, die; bacteria feed on them/bacteria population increases; bacteria use oxygen; removal of oxygen kills fish; [max 3] (c) reference to (less) photosynthesis; so less carbon dioxide removed; trees burned; producing carbon dioxide; [max 2] [Total: 7] 4 (a) chain of three carbon atoms joined by single bonds; eight hydrogen atoms correctly bonded to carbon; [2] e.g. (b) boiling range/point is lower at B than C; because (mean) intermolecular attraction lower; so less (heat) energy needed to separate molecules/boil the mixture; intermolecular attraction is lower for smaller molecules; [max 3] (c) (i) too reactive/compounds much more stable; [1] (ii) sodium atoms lose one electron/outer shell electron/become 2.8; chlorine atoms gain one electron/complete their outer shell become 2.8.8; [2] [Total: 8]

Page 4 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0653 31 © Cambridge International Examinations 2013 5 (a) (i) calcium; [1] (ii) water; [1] (iii) has more calcium; for, teeth/bones; [2] (iv) calcium; can be absorbed as it is/idea that it consists of small particles; [2] (b) (i) to speed up the process; ref. enzymes; idea of enzymes working faster at this temperature; [max 2] (ii) slows enzymes working/to keep it fresh; [1] (iii) acid produced; [1] [Total: 10] 6 (a) (i) work = force × distance; Y’s work is 100 J and X’s work is 120 J; [2] (so X does the most work) (ii) (worker X) reference to power = work/time; (so worker X uses more power) [1] (iii) (density =) mass/volume; = 5000/5500 = 0.91 (g/cm3); [2] (b) (i) working; 288 m; [2] (ii) 240 s; [1] (iii) boy C (no mark) line on graph goes down so speed was changing/owtte ; [1] (answer must show that the graph has been used) [Total: 9]

Page 5 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0653 31 © Cambridge International Examinations 2013 7 (a) carbon dioxide; limewater reacts with carbon dioxide/limewater is the test reagent for CO2; [2] (b) (i) X shown clearly on graph at 2 min; [1] (ii) decrease of; 7 °C; [2] (–7 °C scores both) (iii) (reaction is) endothermic/temperature (of the mixture) decreases; thermal/heat/kinetic energy converted to (internal) chemical energy; [2] (c) sodium ion is Na+; charges of ions must balance; so hydrogencarbonate is HCO3 -; [3] [Total: 10]

Page 6 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0653 31 © Cambridge International Examinations 2013 8 (a) [2] (b) large surface area; good blood supply; thin wall; moist surface; [max 2] (c) mucus traps, bacteria/pathogens/dust/particles; cilia sweep mucus, upwards/away from lungs/to throat; [2] (d) (i) 3, 4 and 5 ; [1] (ii) ref. to bronchitis/inflammation in airways; (because) more mucus produced/damaged cilia unable to remove mucus (as efficiently); in which bacteria breed; ref. to named smoking-induced cancer e.g. lung, throat; ref. to emphysema/breakdown of alveolar walls; so gas exchange less efficient/difficult to get enough oxygen; [max 3] (allow other correct health-related conditions or consequences of smoking) [Total: 10] trachea bronchus

Page 7 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0653 31 © Cambridge International Examinations 2013 9 (a) All symbols correct; Ammeter in series and voltmeter in parallel; Everything else correct; [3] (b) V = IR; R = 0.3/0.5 = 0.6 Ω; [2] (c) Metals contract when cold; If cables put up tight in summer/when warm, cables could snap or pylons could be damaged when temperature falls/in winter; [2] [Total: 7]