Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2015 May/June Paper 3 · Variant 3

This document consists of 28 printed pages. DC (RW/FD) 97580/4 © UCLES 2015 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 5 8 6 7 6 6 2 9 5 1 * CO-ORDINATED SCIENCES 0654/33 Paper 3 (Extended) May/June 2015 2 hours 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 an HB soft pencil for any diagrams, graphs, tables or rough working. 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.

2 0654/33/M/J/15 © UCLES 2015 1 Table 1.1 shows some information about three elements A, B and C. Table 1.1 element group number in Periodic Table number of outer electrons in one atom reactive or unreactive A 1 B 7 reactive C 8 (a) Add the five missing pieces of information to complete Table 1.1. [3] (b) The diagrams, D, E and F, in Fig. 1.1 show the structures of three materials. ' ( ) Fig. 1.1 Deduce which diagram shows an alloy and explain why. diagram showing an alloy … explanation … … …[2]

3 0654/33/M/J/15 © UCLES 2015 [Turn over (c) Fig. 1.2 shows a small piece of sodium reacting in ethanol at 25 °C. In this reaction hydrogen gas is given off. hydrogen gas measuring cylinder sodium ethanol Fig. 1.2 (i) State how the rate of reaction in Fig. 1.2 would be different if the temperature of the ethanol was 10 °C. Explain your answer in terms of collisions between particles. … … … …[3] (ii) The total volume of hydrogen produced by the reaction shown in Fig. 1.2 is 8.4 cm3. Calculate the number of moles of hydrogen in 8.4 cm3. The molar volume of gas at 25 °C is 24 dm3. Show your working. number of moles = …[2]

4 0654/33/M/J/15 © UCLES 2015 2 (a) Fig. 2.1 shows the electrical circuit for a torch (flashlight). Fig. 2.1 (i) Each cell provides a voltage of 1.5 V. State the total voltage across the lamp when the switch is closed. …V [1] (ii) 0.9 A passes through the lamp for one minute. Calculate the charge which passes through the lamp. State the formula that you use, show your working and state the unit of your answer. formula working charge = … unit …[3] (iii) Two students are discussing the current flowing in the circuit. Student A says that the electrons flow in a clockwise direction. Student B says that the conventional current flows in an anti-clockwise direction. Explain why both students are correct. … … … …[2]

5 0654/33/M/J/15 © UCLES 2015 [Turn over (b) The lamp from the torch has a resistance of 5 Ω when lit. Two lamps, identical to the torch lamp, are connected together in a parallel circuit as shown in Fig. 2.2. Fig. 2.2 Calculate the combined resistance of the two lamps. State the formula that you use and show your working. formula working resistance = …Ω [2] (c) Fig. 2.3 shows a ray of light from the torch that is reflected by a plane mirror. $ ' plane mirror torch % & Fig. 2.3 (i) Name angle B and angle C. angle B … angle C … [1] (ii) State what happens to the value of angle C when the value of angle B is doubled. …[1]

6 0654/33/M/J/15 © UCLES 2015 3 A person is infected with the human immunodeficiency virus (HIV). The graph in Fig. 3.1 shows changes over the next ten years in • the concentration of HIV particles in the person’s blood, • the concentration of white cells in their blood. 0 1 2 3 4 5 6 7 8 9 10 concentration of HIV particles in the blood concentration of white cells in the blood time after infection / years concentration / arbitrary units Fig. 3.1 (a) Suggest two ways in which this person may have become infected with HIV. 1 … 2 …[2] (b) Describe how the concentration of HIV particles in this person’s blood changed (i) during the first year after infection, … …[1] (ii) over the next nine years. … …[1]

7 0654/33/M/J/15 © UCLES 2015 [Turn over (c) Suggest a reason why the concentration of white blood cells (i) increases during the first year, … …[1] (ii) decreases over the next nine years. … …[1] (d) Describe and explain what effect the decrease in concentration of white blood cells is likely to have on the infected person. … … …[2] (e) Give two ways in which the government of a country can prevent the spread of HIV / AIDS within a population. 1 … 2 …[2]

8 0654/33/M/J/15 © UCLES 2015 4 (a) A student rubs a balloon on his sweater. Charged particles move from the sweater to the balloon which becomes negatively charged. (i) Name the charged particles. … [1] (ii) The student charges a second balloon in the same way. Fig. 4.1 shows the two charged balloons next to each other. Fig. 4.1 State what happens to the balloons when the student brings the balloons very close together. Explain your answer. … … …[2]

9 0654/33/M/J/15 © UCLES 2015 [Turn over (b) The student then bursts one of the balloons some distance from a brick wall. This is shown in Fig. 4.2. student balloon brick wall Fig. 4.2 The noise the balloon makes when it bursts travels through the air as a sound wave. The student hears an echo. (i) Explain why the student hears an echo. … …[1] (ii) Sound waves move through the air as a series of compressions and rarefactions. State the difference between a compression and a rarefaction. … … …[1] (iii) The speed of sound in air is about 330 m / s. In water the speed of sound is about 1500 m / s. Suggest, using ideas of distances between molecules and the movement of molecules, why the speed of sound is greater in water than in air. … … … …[2]

10 0654/33/M/J/15 © UCLES 2015 (c) Fig. 4.3 shows a large hot air balloon moving upwards. upward force = 8200 N weight = 7850 N Fig. 4.3 The mass of the hot air balloon is 785 kg. Calculate the acceleration of the balloon. State the formula that you use and show your working. formula working acceleration = …m / s2 [2]

11 0654/33/M/J/15 © UCLES 2015 [Turn over 5 Millions of tonnes of sodium chloride are extracted from the Earth’s crust every year. (a) (i) Name the type of chemical bonding found in sodium chloride. …[1] (ii) Fig. 5.1 shows an unlabelled diagram of the structure of sodium chloride. Fig. 5.1 On Fig. 5.1, complete the diagram to show the sodium chloride structure by labelling all of the particles with their chemical symbols and electrical charges. [2]

12 0654/33/M/J/15 © UCLES 2015 (b) Pure sodium chloride is used to make chlorine. Fig. 5.2 shows industrial apparatus used to obtain chlorine. chlorine gas electrodes gas * solution 6 permeable membrane  Fig. 5.2 (i) State what must be done to the pure sodium chloride before it can be used in the process shown in Fig. 5.2. …[1] (ii) Name gas G and solution S in Fig. 5.2. gas G … solution S … [2] (iii) Describe in terms of ions, atoms and electrons what happens on the surface of the anode to produce chlorine gas molecules, Cl2. … … … …[3] (c) Phosphorus trichloride, PCl3, is formed when chlorine gas reacts with phosphorus molecules. The formula for a phosphorus molecule is P4. Construct a balanced equation for the formation of phosphorus trichloride. …[2]

13 0654/33/M/J/15 © UCLES 2015 [Turn over 6 (a) Fig. 6.1 shows part of a leaf in section, as it appears under a microscope. : ; Fig. 6.1 (i) On Fig. 6.1, draw an arrow to show the path taken by water vapour as it goes from the cell labelled W to the outside atmosphere. [1] (ii) Name the pore in the leaf labelled X. …[1] (b) Another leaf of the same size is similar in structure to Fig. 6.1, has larger air spaces and more pores. Suggest and explain what effect these features will have on the rate at which this leaf loses water to the atmosphere. (i) effect of having larger air spaces … explanation … …[2] (ii) effect of having more pores … explanation … …[2] (c) In very dry environments, such as deserts, plants have leaves that are adapted for the dry conditions. Use your answers to part (b) to suggest one way in which a plant’s leaves might be adapted for desert conditions. … …[1]

14 0654/33/M/J/15 © UCLES 2015 7 Oxygen combines with many elements to form oxides. (a) Fig. 7.1 shows two test-tubes, J and K, that a student set up to investigate the oxidation of iron. - . iron nail gauze dry air only water drying agent removes water vapour Fig. 7.1 (i) State the common name of the iron oxide that is formed in this experiment. …[1] (ii) State and explain whether the oxide in (i) is formed in test-tube J, in test-tube K or in both. oxide formed in … explanation … …[1] (b) Table 7.1 shows some information about six oxides. Table 7.1 name formula physical state at 20 °C pH after shaking with pure water aluminium oxide Al2O3 solid 7 copper oxide CuO solid 7 nitrous oxide N2O gas 7 potassium oxide K2O solid 13 Q solid 1 sulfur dioxide SO2 gas 2

15 0654/33/M/J/15 © UCLES 2015 [Turn over (i) Name the elements that combine with oxygen to form the neutral oxides in Table 7.1. elements … explanation … …[2] (ii) The elements calcium and phosphorus both form white, solid oxides. Use the information in Table 7.1 to deduce whether oxide Q is calcium oxide or phosphorus oxide. Explain your answer. … … …[2] (c) The word equation for the burning of magnesium in air is shown below. magnesium + oxygen magnesium oxide State and explain whether the chemical potential energy of the product is greater than, less than, or the same as the chemical potential energy of the reactants. … … …[2] (d) Complete the word chemical equation which shows the oxidation of sulfur dioxide during the Contact Process. + [2] (e) Name the substance that reacts with copper oxide to produce a solution containing the salt, copper sulfate. …[1]

16 0654/33/M/J/15 © UCLES 2015 8 (a) Coal is burned in a power station to generate electricity. Fig. 8.1 is a scale diagram to show the energy transformations in a coal-burning power station. electrical power = 1.2 MW rate of input energy from fuel = 4.0 MW rate of energy transferred to the surroundings = 2.8 MW 1 MW = 1 000 000 W Fig. 8.1 Calculate the efficiency of the power station as a percentage. Show your working. efficiency = …% [2] (b) Nuclear fuel can also be used in power stations to generate electricity. In a nuclear power station, nuclear fission of uranium-235 takes place. (i) State what happens to the uranium-235 during nuclear fission. … …[1] (ii) A different nuclear process takes place in the Sun to release energy from hydrogen. Name this process and describe what happens to the hydrogen during this process. name of process … description … …[2]

17 0654/33/M/J/15 © UCLES 2015 [Turn over (c) When electricity has been generated in a power station, a step-up transformer increases the voltage before the electricity is transmitted through long-distance cables. (i) Explain why the voltage of the electricity is increased before transmission. … … …[2] (ii) The power station generates electricity at 33 000 V. The voltage is stepped up by a transformer. The number of turns on the primary coil of the transformer is 40 000. The number of turns on the secondary coil of the transformer is 500 000. Calculate the output voltage from the transformer. State the formula that you use and show your working. formula working output voltage = … V [2]

18 0654/33/M/J/15 © UCLES 2015 The burning of fossil fuels can cause acid rain and may also lead to global warming. (d) Name a gas produced from burning fossil fuels that can lead to acid rain. …[1] (e) Describe why acid rain may kill plants, … … animals living in lakes. … … [2] (f) Describe how the gases produced from burning fossil fuels cause global warming. … … …[2]

19 0654/33/M/J/15 © UCLES 2015 [Turn over Please turn over for Question 9.

20 0654/33/M/J/15 © UCLES 2015 9 Frederick Hopkins, a scientist, investigated the effect of diet on the growth of mice. He kept two groups of mice in a laboratory, feeding them on different diets. • Group 1 had a basic diet of purified protein, carbohydrate, fat and mineral ions. They also had plenty of water. • Group 2 had a supplemented diet. This was exactly the same as the basic diet, but with a small amount of milk added. Hopkins measured the average mass of the mice in each group over a period of 18 days. After 18 days, he reversed the diets. Fig. 9.1 shows his results. 0 10 40 50 60 70 80 90 20 30 40 50 average mass of animals / g day milk supplement started milk supplement stopped group  group  Fig. 9.1 (a) Compare the growth of the group 1 and group 2 animals between day 0 and day 9. Include in your answer how the growth of each group is alike and how the growth of each group is different. … … …[2]

21 0654/33/M/J/15 © UCLES 2015 [Turn over (b) State one function, in the diets, of (i) the protein, …[1] (ii) the carbohydrate. …[1] (c) Name one mineral ion that the mice would need in their diet, and state its function. mineral ion … function … …[2] (d) Suggest one nutrient, normally present in a balanced diet, that was present in the milk but absent from the basic diet. …[1] (e) In Hopkins’s experiment, he used mice from the same litter. Explain why it was important that the group 1 and group 2 mice came from the same litter. … …[1] (f) (i) Explain why the diets of the two groups were swapped after 18 days. … … …[1] (ii) Suggest what would have happened to the mice in group 1 if the diets had been swapped back again after 36 days. Give a reason for your answer. … …[1] (g) Hopkins’s experiment was about nutrition. Define nutrition. … … … …[2]

22 0654/33/M/J/15 © UCLES 2015 10 The diagrams in Fig. 10.1 represent the structures of four substances L, M, N and O, all of which contain carbon. Some of these substances also contain oxygen or hydrogen. / 0 2 1 Fig. 10.1 (a) (i) State and explain one substance in each case, chosen from the structures L, M, N and O, that represents an element, … explanation … … a compound. … explanation … … [2]

23 0654/33/M/J/15 © UCLES 2015 [Turn over (ii) Deduce which substance L, M, N or O, in Fig. 10.1 could be a hydrocarbon. substance … explanation … …[1] (iii) Deduce which substance L, M, N or O, in Fig. 10.1 is produced when each of the other three substances undergoes complete combustion. substance … explanation … … …[2] (b) Fig. 10.2 shows the structure of propane. H H H H H H H H C C C Fig. 10.2 (i) Name the type of chemical bonding that holds the atoms together in this molecule. …[1] (ii) State and explain the total number of shared pairs of electrons in the molecule shown in Fig. 10.2. number of pairs of electrons … explanation … …[2]

24 0654/33/M/J/15 © UCLES 2015 11 (a) State the balanced chemical equation for aerobic respiration. …[2] (b) State how anaerobic respiration differs from aerobic respiration in terms of (i) substances reacting, …[1] (ii) amount of energy released. …[1] (c) Explain why anaerobic respiration of yeast is important in the brewing of beer. … … …[2]

25 0654/33/M/J/15 © UCLES 2015 [Turn over 12 (a) A police car communicates with the police station using radio waves. The police car uses a blue flashing light to alert people. Radio waves and light waves are both parts of the electromagnetic spectrum. (i) State one property which all electromagnetic waves have in common. …[1] (ii) State one property which is different for different electromagnetic waves. … …[1] (iii) Blue light waves have a frequency of 6.7 × 1014 Hz. The speed of the waves is 3.0 × 108 m / s. Calculate the wavelength of blue light waves. State the formula that you use and show your working. formula working wavelength = …m [2] (iv) Fig. 12.1 shows a wave. $ % & ' ( Fig. 12.1 State which measurement, A, B, C, D or E is the amplitude of the wave, … the wavelength of the wave. … [1]

26 0654/33/M/J/15 © UCLES 2015 (b) Fig. 12.2 shows the motion of the police car over two minutes. 0 0 1 2 time / minutes speed m/s 10 20 30 40 Fig. 12.2 (i) Use the graph to calculate the distance covered by the police car during the two minutes. Show your working. distance = …m [2] (ii) Label, with a letter A and a label line, a point on the graph where the car is accelerating. [1] (iii) Calculate the acceleration you identified in (ii). Show your working. formula working acceleration = …m / s2 [2]

27 0654/33/M/J/15 © UCLES 2015 (iv) The mass of the car is 1200 kg. Calculate the kinetic energy of the car when it is travelling at the constant speed shown in the graph. State the formula that you use and show your working. formula working kinetic energy = …J [2]

28 0654/33/M/J/15 © UCLES 2015 To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series. Group The Periodic Table of the Elements 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 91 238 231 147 237 244 243 247 247 251 252 257 258 259 260 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 82 209 209 210 222 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 55 226 223 Ra Radium 88 a X b a = relative atomic mass X = atomic symbol b = atomic (proton) number Key DATA SHEET * 58–71 Lanthanoid series † 90–103 Actinoid series The volume of one mole of any gas is 24dm3 at room temperature and pressure (r.t.p.).

® IGCSE is the registered trademark of Cambridge International Examinations. CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International General Certificate of Secondary Education MARK SCHEME for the May/June 2015 series 0654 CO-ORDINATED SCIENCES 0654/33 Paper 3 (Extended Theory), maximum raw mark 120 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 2015 series for most Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level components.

Page 2 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0654 33 © Cambridge International Examinations 2015 1 (a) element Group number in Periodic Table Number of outer electrons in one atom reactive / unreactive A (1) 1 reactive B (7) 7 (reactive) C 0 (8) unreactive (1 for each column correct) ; ; ; [3] (b) (D) an alloy is a mixture of metals ; E is not a mixture / is only one substance / is pure / single metal ; F does not show metals / is a mixture of gases / is a mixture of compounds ; [max 2] (c) (i) reaction rate is lower ; (ethanol) molecules have lower average energy / are moving more slowly ; so frequency of collision with sodium is lower ; lower chance of successful collision ; R: there are fewer collisions [max 3] (ii) molar volume 24 000 cm3 ; 8.4 ÷ 24 000 = 0.00035 ; (allow 1 mark for 8.4 ÷ 24 = 0.35) OR volume of hydrogen 0.0084 dm3 ; 0.0084 ÷ 24 = 0.00035 ; [2] [Total: 10] 2 (a) (i) 4.5 (V) ; [1] (ii) (charge =) current × time ; = 54 ; coulombs (C) ; [3] (iii) conventional current flows from positive to negative ; (electric current) is flow of negative charged electrons / electrons / charge / electricity flow / s from negative to positive ; [2] (b) working or 1 / R = 1 / R1 + 1 / R2 or (R =) R1R2 / R1+R2 ; R = 2.5 (Ω) ; [2]

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0654 33 © Cambridge International Examinations 2015 (c) (i) B (angle of) incidence C (angle of) reflection ; (both required for mark) [1] (ii) angle C will double ; [1] [Total: 10] 3 (a) sex / exchange of sexual fluids ; shared needles ; (contaminated) blood transfusion / exchange of blood ; mother to baby ; [max 2] (b) (i) increased and then decreased ; [1] (ii) increased ; [1] (c) (i) response to infection / pathogen ; [1] (ii) cells destroyed by virus / disease ; A: killed [1] (d) immune system is suppressed ; more likely to suffer from other diseases / reduced resistance to infection ; because less antibody production ; [2] (e) education ; screening blood transfusions ; (encouraging) use of condoms / barrier contraception ; free needles for drug addicts / (encouraging) not sharing ; AVP ; [max 2] [Total: 10] 4 (a) (i) electrons ; [1] (ii) move apart / repel ; because like charges repel each other ; [2] (b) (i) sound waves are reflected ; [1] (ii) compressions are regions where the particles in air are close together / rarefactions are regions where the particles in air are spread out ; compressions are regions with air at higher pressure than normal / rarefactions are regions with air at lower pressure than normal ; [1]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0654 33 © Cambridge International Examinations 2015 (iii) particles collide more quickly ; particles closer together ; [2] (c) (acceleration =) force / mass ; acceleration = 350 / 785 = 0.45 (m / s2) ; [2] [Total: 9] 5 (a) (i) ionic / electrovalent ; [1] (ii) correct symbols show alternating sodium and chloride in both directions ; indication that particles are positive sodium ions and negative chloride ions ; [2] (b) (i) dissolve in water / make a solution ; [1] (ii) hydrogen ; sodium hydroxide ; [2] (iii) chloride ions lose electrons ; reference to ions discharged / (each loses) one electron ; (resulting) chlorine atoms combine in pairs ; chlorine atoms form covalent bond / share a pair of electrons ; [max 3] (c) P4 + 6Cl 2 → 4PCl 3 [2] all formulae ; and then balanced ; [2] [Total: 11] 6 (a) (i) arrow from cell and out through stoma ; [1] (ii) stoma / stomata ; [1] (b) (i) faster water loss ; faster / more evaporation ; [2] (ii) faster water loss ; more escape routes (for diffusion) ; [2] (c) smaller air spaces / fewer pores ; [1] [Total: 7]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0654 33 © Cambridge International Examinations 2015 7 (a) (i) rust ; [1] (ii) (K) (rusting requires) air / oxygen and water present (together) ; [1] (b) (i) nitrogen ; ignore aluminium / copper reference to pH 7 in water ; [2] (ii) (phosphorus oxide) forms an acidic oxide ; means that it must be a non-metal oxide and phosphorus is a non-metal ; [2] (c) (less) reaction is exothermic / gives out heat / thermal energy ; the idea that chemical energy (of reactants) is transferred to surroundings / released as heat / thermal energy, so less chemical energy remains ; [2] (d) sulfur dioxide + oxygen → sulfur trioxide (reactants and products) ; ; [2] (e) (dilute) sulfuric acid ; [1] [Total: 11] 8 (a) useful power output / total power input OR working (1.2 / 4.0) OR useful energy output / total energy input OR working (1.2 / 4.0) ; = 30 (%) ; [2] (b) (i) nuclei split ; [1] (ii) (nuclear) fusion ; nuclei fuse / join together ; [2] (c) (i) to reduce current ; to reduce power / energy losses ; [2] (ii) Vs / Vp = Ns / Np ; output voltage = 500 000 × 33 000 / 40 000 = 412 500 (V) ; [2] (d) sulfur dioxide / nitrogen oxide ; [1]

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0654 33 © Cambridge International Examinations 2015 (e) damages leaves / kills animals ; acidifies soils ; leaches mineral ions from soil ; acidifies water ; toxic compounds soluble in acidic water ; denatures enzymes ; [max 2] (f) ref to CO2 ; trap solar radiation / greenhouse effect ; (re-)radiate it back to Earth ; [max 2] [Total: 14] 9 (a) both increasing ; group 2 increasing faster / more ; [2] (b) (i) growth / repair ; [1] (ii) energy ; [1] (c) calcium ; for bones ; OR iron ; for blood ; [2] (d) (named) vitamin ; [1] (e) genetically similar / so this is not a variable ; [1] (f) (i) a control / shows that the difference is due to the diet / not due to the mice ; [1] (ii) grow more slowly / decreases, because no milk / vitamins ; OR continue to grow (for a while), as Group 2 did ; [1] (g) taking in nutrients / organic substances and ions ; containing raw materials / energy ; absorbing / assimilating them ; [max 2] [Total: 12]

Page 7 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0654 33 © Cambridge International Examinations 2015 10 (a) (i) (L or O) contain only one type of atom / contain only carbon atoms ; (M or N) more than one type of atom / elements bonded together ; [2] (ii) (M) idea that no hydrocarbon has less than five atoms / could be butane / C4H10 / contains C and H atoms but could not be CH2 or C2H / N is CO2 / other logical deductive statement ; [1] (iii) (N) this must be carbon dioxide ; supporting detail, e.g. only one with three bonded atoms / fits the formula CO2 / double bonds ; [2] (b) (i) covalent ; [1] (ii) 10 ; there are ten (single) bonds / each (single) bond represents a shared pair ; [2] [Total: 8] 11 (a) C6H12O6 + 6O2 = 6CO2 + 6H2O (one mark for correct formulae, one mark for balanced equation) ; ; [2] (b) (i) does not use oxygen ; [1] (ii) releases less energy ; [1] (c) produces alcohol / ethanol ; produces carbon dioxide / makes “fizzy” / AW ; [2] [Total: 6] 12 (a) (i) speed / transverse waves / passes through vacuum ; [1] (ii) frequency or wavelength ; [1] (iii) wavelength = velocity / frequency ; wavelength = 3.0 × 108 = 4.5 × 10–7 (m) ; 6.7 × 1014 [2] (iv) amplitude: B and wavelength: E ; (both required in this order) [1]

Page 8 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0654 33 © Cambridge International Examinations 2015 (b) (i) area under graph or evidence of working ; = (90 × 40) + (½ × 30 × 40) = 3600 + 600 = 4200 (m) ; [2] (ii) A written anywhere on section from 1½–2 minutes ; [1] (iii) (acceleration =) change in speed / time = 40 / 30 ; = 1.3 (m / s2) ; [2] (iv) (kinetic energy =) ½ mv2 ; = ½ x 1200 × 40 × 40 = 960 000 (J) ; [2] [Total: 12]