Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2014 May/June Paper 3 · Variant 1

This document consists of 32 printed pages. IB14 06_0654_31/4RP © UCLES 2014 [Turn over *8044033067* Cambridge International Examinations Cambridge International General Certificate of Secondary Education CO-ORDINATED SCIENCES 0654/31 Paper 3 (Extended) May/June 2014 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 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 32. 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 © UCLES 2014 0654/31/M/J/14 1 (a) Complete the following sentences about chemical bonding choosing words from the list below. Each word may be used once, more than once or not at all. electrons ions lost molecules neutralised nucleons shared transferred When a covalent bond forms, are between atoms. When an ionic bond forms, are between atoms. [2] (b) Complete the dot-and-cross diagram of one molecule of carbon dioxide. The diagram should show the chemical symbols of the elements and the arrangement of only the outer electrons of the atoms. [3] (c) A metal displacement reaction may occur when a metal is placed into an aqueous solution of a salt of a different metal. Metals L, M and N are added to solutions of the nitrates of the same three metals. Table 1.1 shows whether or not a displacement reaction occurs. Table 1.1 metal L metal M metal N metal L nitrate solution no reaction reaction metal M nitrate solution reaction reaction metal N nitrate solution no reaction no reaction

3 © UCLES 2014 0654/31/M/J/14 [Turn over (i) Use the results in Table 1.1 to place the three metals, L, M and N, into order according to their relative reactivity starting with the most reactive. (most reactive) [1] (ii) Explain your answer to (i). [3] (iii) A metal displacement reaction occurs when magnesium is placed into a solution of silver nitrate. This reaction may be represented by the ionic equation Mg(s) + 2Ag+(aq) Mg2+(aq) + 2Ag(s) Using the idea of electron transfer, explain why this is an example of a redox reaction. [2]

4 © UCLES 2014 0654/31/M/J/14 2 Fig. 2.1 shows an insect-pollinated flower cut through lengthways. Z X Y Fig. 2.1 (a) Name the structures labelled X and Y. X Y [2] (b) State the function of the part labelled Z. [1] (c) Name the part of the flower in which the seeds will develop if the flower is pollinated. [1] (d) State two ways, shown in Fig. 2.1, in which this flower is adapted for pollination by insects. 1 2 [2] (e) Grass flowers are usually pollinated by the wind. State two ways in which the structure of a grass flower would be different from the flower in Fig. 2.1. 1 2 [2]

5 © UCLES 2014 0654/31/M/J/14 [Turn over (f) A scientist did a genetic experiment in which she crossed flowers from two different plants, A and B, of the same species. This is the procedure that she used. • The immature stamens were removed from a flower of plant A. • This flower was then covered with a plastic bag. • When the flowers on both plants were mature, a small paintbrush was used to transfer pollen from plant B to plant A. • The plastic bag was put back to cover the flower of plant A again. • The flower inside the plastic bag produced seeds, which were then allowed to germinate and grow. In this procedure, suggest why (i) the stamens were removed from the flowers of plant A, [1] (ii) the flower of plant A was kept covered by a plastic bag. [1]

6 © UCLES 2014 0654/31/M/J/14 3 Fig. 3.1 shows information about two trucks, X and Y, coming to rest under the action of the same braking force. mass = 2000 kg truck X 15 m / s mass = 3000 kg truck Y 15 m / s load Fig. 3.1 The mass of truck X is 2000 kg and the mass of truck Y and its load is 3000 kg. Fig. 3.2 shows the speed / time graph for the two trucks. X Y 0 10 20 30 time / s 40 50 60 20 15 10 5 0 speed / m per s X Y Fig. 3.2 (a) (i) Explain how Fig. 3.2 shows that truck X has the greater deceleration. [1]

7 © UCLES 2014 0654/31/M/J/14 [Turn over (ii) Calculate the deceleration of truck Y. Show your working. deceleration = m / s2 [2] (iii) The deceleration of truck X is 0.5 m / s2. Calculate the braking force on truck X. State the formula that you use and show your working. State the units of your answer. formula working force = unit [2]

8 © UCLES 2014 0654/31/M/J/14 (b) The density of the metal used to make the load carried by truck Y is 2700 kg / m3. The mass of the load is 1000 kg. Calculate the volume of the load. State the formula that you use and show your working. State the unit of your answer. formula working volume = unit [3] (c) The metal block needs 1820 kJ of thermal energy to raise its temperature by 2 °C. Calculate the specific heat capacity of the metal in the block. State the formula that you use and show your working. formula working specific heat capacity = kJ / (kg °C) [3]

9 © UCLES 2014 0654/31/M/J/14 [Turn over Please turn over for Question 4.

10 © UCLES 2014 0654/31/M/J/14 4 Fuels react with oxygen in combustion reactions. During these reactions, heat energy is released. (a) (i) Name and state a use for a gaseous fuel. name use [2] (ii) State the word used to describe chemical reactions that release heat energy. [1] (b) When some fuels are burned, the mixture of combustion products contains sulfur dioxide and oxides of nitrogen. State two harmful effects of these gases in the environment. 1 2 [2] (c) Charcoal is a solid fuel that contains mainly the element carbon. Large pieces of charcoal burn slowly. Charcoal in the form of a fine powder burns very quickly. (i) Explain, in terms of the collision theory of rate of reaction, why charcoal powder burns more quickly than large pieces of charcoal. [2]

11 © UCLES 2014 0654/31/M/J/14 [Turn over reactants product carbon + oxygen carbon dioxide Fig. 4.1 (ii) The reactants and the product for the complete combustion of carbon are shown in Fig. 4.1. Predict and explain whether the product contains a greater, smaller or the same total amount of chemical potential energy compared to the reactants. prediction explanation [2]

12 © UCLES 2014 0654/31/M/J/14 5 (a) In a domestic lighting circuit, lamps are connected in parallel. Explain why the lamps are not connected in series. [2] (b) (i) Explain why a balloon rubbed with a woollen cloth gains a negative electric charge. [2] Fig. 5.1 shows two similarly charged balloons, suspended close together. Fig. 5.1 (ii) Explain why the two balloons move apart. [1] (c) Describe how a circuit breaker protects a worker using an electric drill. [1]

13 © UCLES 2014 0654/31/M/J/14 [Turn over (d) Explain why energy losses in overhead electricity transmission cables are lower when the voltage is high. [2]

14 © UCLES 2014 0654/31/M/J/14 6 Fig. 6.1 shows part of a food web in African grassland (savannah). zebra impala lion cheetah hyena baboon grasses trees insects serval leopard mongoose Fig. 6.1 (a) The savannah is an ecosystem. Define an ecosystem. [2] (b) Use the information in Fig. 6.1 to write down a food chain containing five organisms. [2] (c) (i) Explain why food chains rarely have more than five trophic levels. [1] (ii) With reference to Fig. 6.1, explain why there are fewer lions than zebras. [1]

15 © UCLES 2014 0654/31/M/J/14 [Turn over (d) The food web in Fig. 6.1 does not show any decomposers. (i) Define the term decomposer. [1] (ii) Name one type of organism that is a decomposer. [1] (iii) State on which organisms in Fig. 6.1 the decomposers would feed on. [1] (iv) Explain why decomposers are important for the grasses and trees in the ecosystem. [1]

16 © UCLES 2014 0654/31/M/J/14 7 (a) Fig. 7.1 shows a chlorine atom that has a nucleon number (mass number) of 35. Fig. 7.1 Two types of particle are found in the nucleus of this atom. Complete Table 7.1 with the names and numbers of these particles in the nucleus of this chlorine atom. Table 7.1 name of particle number in the nucleus [2] (b) (i) Explain why chlorine is added to water that will be used for drinking. [1] (ii) Suggest the word chemical equation for the reaction that occurs when chlorine is mixed with sodium iodide solution. [1]

17 © UCLES 2014 0654/31/M/J/14 [Turn over (c) Fig. 7.2 shows a simplified diagram of the electrolysis of sodium chloride solution, used to produce chlorine in industry. + – concentrated sodium chloride solution chlorine gas hydrogen gas sodium hydroxide solution permeable membrane anode cathode Fig. 7.2 The balanced equation for the overall chemical change that occurs in the process shown in Fig. 7.2 is 2NaCl + 2H2O → 2NaOH + Cl2 + H2 (i) Show that the relative formula mass of sodium chloride is 58.5. [1] (ii) Calculate the number of moles in 234 g of sodium chloride. Show your working. number of moles = [1]

18 © UCLES 2014 0654/31/M/J/14 (iii) Calculate the volume of chlorine molecules produced at room temperature and pressure, when 234 g of sodium chloride are electrolysed. (1 mole of chlorine molecules has a volume of 24 dm3 at room temperature and pressure.) Show your working. volume = [2] (iv) Explain why chlorine is given off at the anode in this process. Your answer should refer to • the movement of ions, atoms and electrons, • the reactions involving ions, atoms and electrons. [3]

19 © UCLES 2014 0654/31/M/J/14 [Turn over 8 (a) Electricity can be generated by burning fossil fuels in a power station. Describe how the energy released from the fossil fuel is used to produce electrical energy. [3] (b) In some power stations highly radioactive isotopes are formed when energy is released. Workers at these power stations are monitored to check their exposure to radiation. (i) State one way in which a worker’s exposure to radiation can be monitored. [1] (ii) State one effect of ionising radiation on the human body. [1] (c) Gamma radiation is one form of ionising radiation. Gamma radiation is part of the electromagnetic spectrum. State the part of the electromagnetic spectrum which is used for terrestrial television communications, mobile telephone (cell phone) communications, television remote control. [1]

20 © UCLES 2014 0654/31/M/J/14 (d) Fig. 8.1 and Fig. 8.2 show a perspective view and an end view of a simple a.c. generator. Fig. 8.2 also shows the magnetic field lines between the poles of the magnet. perspective view of generator N S magnet coil axle Fig. 8.1 end view of generator N S coil magnetic field axle Fig. 8.2 Complete the diagrams to show the positions of the coil when the current produced is (i) zero, N S axle [1] (ii) maximum. N S axle [1]

21 © UCLES 2014 0654/31/M/J/14 [Turn over (e) On the grid in Fig. 8.3, sketch a graph of voltage against time for two rotations of the coil in this simple a.c generator. voltage time 0 Fig. 8.3 [3]

22 © UCLES 2014 0654/31/M/J/14 9 Some washing powders contain enzymes that digest fats. These enzymes help in the removal of greasy stains in clothing. (a) Name the type of enzyme that digests fats. [1] (b) The graph in Fig. 9.1 shows the effect of temperature on the activity of two different fat-digesting enzymes from different washing powders. enzyme enzyme 1 enzyme enzyme 2 0 10 20 30 40 50 60 temperature / °C enzyme activity enzyme 1 enzyme 2 Fig. 9.1 (i) State the temperature at which both enzymes are working, and have the same activity. temperature °C [1] (ii) Explain why both enzymes work very slowly at 10 °C. [2] (iii) Explain why the enzymes do not work at all above 60 °C. [1]

23 © UCLES 2014 0654/31/M/J/14 [Turn over (c) Most washing machines have a standard programme that washes clothes at 40 °C. Some machines also have an ‘ECO’ programme that washes at 30 °C. (i) Explain why the ‘ECO’ programme is thought to be better for the environment than the standard programme. [2] (ii) Suggest which of the two enzymes in Fig. 9.1 should be used in a washing powder designed for use in a washing machine with an ‘ECO’ programme. Explain your answer. enzyme explanation [2] (d) Enzymes are proteins. Describe a test that you could do on a solution of washing powder to see if it contained protein. [2]

24 © UCLES 2014 0654/31/M/J/14 10 (a) Thunder and lightning happen at the same time. An observer sees the flash of lightning before he hears the thunder. (i) Explain why the observer sees the lightning before he hears the thunder. [1] (ii) Describe how the sound of the thunder is transmitted to the observer through the air. [1] (iii) An observer in a space station orbiting in a vacuum sees the lightning but does not hear the thunder. Explain why. [1] (b) Ultrasound waves are sound waves with a very high frequency. These waves cannot be heard by human beings. (i) State the approximate range of frequencies audible to humans. Hz to Hz [1]

25 © UCLES 2014 0654/31/M/J/14 [Turn over (ii) Devices which emit ultrasound waves can be used to keep small animals such as cats away from gardens. The ultrasound waves emitted by a device take 0.05 s to travel from the device to a cat. The speed of the ultrasound waves is 330 m / s. Calculate the distance between the ultrasound device and the cat. State the formula that you use and show your working. formula working distance = m [2] (iii) An ultrasound device emits waves with a wavelength of 0.011 m. Calculate the frequency of these waves. State any formula that you use and show your working. formula working frequency = Hz [2]

26 © UCLES 2014 0654/31/M/J/14 (c) A student builds a simple circuit including a buzzer. Fig. 10.1 shows the circuit diagram for the circuit. buzzer 10 Ω Fig. 10.1 When the student closes the switch, the buzzer does not emit a sound. The teacher tells the student that he needs a greater current to make the buzzer work. Redraw the circuit diagram to show two ways in which the student could increase the current flowing through the buzzer. [2]

27 © UCLES 2014 0654/31/M/J/14 [Turn over 11 Fig. 11.1 shows the human heart, as seen from the front. X Fig. 11.1 (a) State the main type of tissue in the heart. [1] (b) (i) Name the blood vessel labelled X. [1] (ii) Describe and explain the effect on the heart tissue if this blood vessel X becomes blocked. [2]

28 © UCLES 2014 0654/31/M/J/14 (c) Table 11.1 shows the rates of heart disease in men and women in two different countries. Table 11.1 country A country B men women men women deaths from heart disease per year per 100 000 people 105 55 80 50 (i) Using information from Table 11.1, describe the differences between the rates of heart disease in the two countries. [2] (ii) Suggest two ways in which someone could change their lifestyle to reduce their chances of suffering from heart disease. 1 2 [2] (iii) Apart from differences in lifestyle, suggest one other possible reason for the difference in rates of heart disease in countries A and B. [1]

29 © UCLES 2014 0654/31/M/J/14 12 (a) The elements are often described as being either metals or non-metals. (i) Describe two differences in the physical properties of a typical metal and a typical non-metal. 1 2 [2] (ii) The element radium has a proton number of 88. Predict and explain briefly whether radium is a metallic or non-metallic element. You may wish to refer to the Periodic Table on page 32. [1] Question 12 continues on page 30.

30 © UCLES 2014 0654/31/M/J/14 (b) Oxides are compounds of oxygen with other elements. A student made four mixtures, W, X, Y and Z, by shaking four oxides in water. He measured the pH values of the mixtures, and his results are shown in Table 12.1. Table 12.1 mixture pH W 3 X 2 Y 12 Z 7 (i) State and explain which mixture was the most acidic. mixture explanation [1] (ii) State and explain in which mixture the oxide had not changed the pH of the water. mixture explanation [1] (iii) State and explain which mixture had been made using the oxide of a metallic element. mixture explanation [1]

31 © UCLES 2014 0654/31/M/J/14 (c) Rust is a type of iron oxide. Fig. 12.1 shows four test-tubes, 1, 2, 3 and 4, that a student set up to investigate the rusting of iron. Each test-tube contained an iron nail and different combinations of a liquid and a gas. water water hydrocarbon oil iron nail air air oxygen nitrogen 1 2 3 4 Fig. 12.1 The test-tubes and their contents were left for a week and then observed. Table 12.2 shows the observations the student made. Table 12.2 test-tube observation 1 no rust 2 rust formed 3 rust formed 4 no rust Explain how the results in each test-tube lead to a conclusion about what is needed for rust to form. [3]

32 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. 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 2014 0654/31/M/J/14 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 2014 series 0654 CO-ORDINATED SCIENCES 0654/31 Paper 3 (Extended), 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 2014 series for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level components and some Ordinary Level components.

Page 2 Mark Scheme Syllabus Paper IGCSE – May/June 2014 0654 31 © Cambridge International Examinations 2014 O C O 1 (a) electrons are shared ; electrons are transferred ; [2] (b) bonding electrons shown as two sets of two shared pairs ; two lone pairs shown on both oxygen atoms ; chemical symbols correctly indicated ; [3] (c) (i) N (most reactive) L M ; [1] (ii) general statement that more reactive metal displaces less reactive metal ; N displaces both / L and M and so is more reactive than them / most reactive ; M displaces neither / L nor N and so is least reactive / less reactive than them ; L displaces M and so is more reactive than M ; L doesn’t displace N and so is less reactive than N ; [max 3] (iii) magnesium (atoms) / Mg lose electrons and are oxidised ; silver (ions) / Ag+ gain electrons and are reduced ; general statement that loss of electrons defined as oxidation AND gain of electrons defined as reduction ; [max 2] [Total: 11] 2 (a) X = stigma / carpel ; Y = sepal ; [2] (b) produces / releases pollen ; [1] (c) ovary ; [1]

Page 3 Mark Scheme Syllabus Paper IGCSE – May/June 2014 0654 31 © Cambridge International Examinations 2014 (d) petals ; anthers / stamens inside the flower ; stigma inside the flower ; lobed stigma ; [max 2] (e) no petals / smaller flowers ; anthers / stamens outside the flower ; stigmas outside the flower ; feathery stigmas ; [max 2] (f) (i) to prevent the flower pollinating itself ; [1] (ii) to prevent other (stray) pollen reaching it / pollination by other plants ; [2] [Total: 10] 3 (a) (i) X – takes less time to stop / speed decreases more quickly / gradient is greater / line is steeper ; [1] (ii) (deceleration =) time speed in change ; 45 15 = 0.33 (m / s2) ; [2] (iii) (force =) mass × acceleration ; = 2000 × 0.5 = 1000 N ; [2] (b) (volume =) density mass ; = 2700 1000 ; = 0.37 m3 ; [3] (c) E = m × c × θ or (c =) θ m Ε ; c = 1000 1820 × 2 ; = 0.91 (kJ / kg °C) ; [3] [Total: 11]

Page 4 Mark Scheme Syllabus Paper IGCSE – May/June 2014 0654 31 © Cambridge International Examinations 2014 4 (a) (i) natural gas / methane / propane / butane / biogas / refinery gas / petroleum gas ; used for heating / cooking / lighting / vehicle fuel / burners ; [2] (ii) exothermic ; [1] (b) reference to acid rain which damages building material / plants / aquatic life ; reference to damage to respiratory system ; other correct e.g. acidity of soil ; [max 2] (c) (i) powder has a greater surface area (mass for mass) ; so greater chance of collision between (carbon and oxygen / air) particles ; reference to higher collision frequency between (carbon and oxygen / air) particles ; [max 2] (ii) smaller / less chemical potential energy in products / owtte ; chemical potential energy (in reactants) is converted to heat energy ; heat (and light) energy is lost / reaction is exothermic ; [max 2] [Total: 9] 5 (a) so that all lamps get full mains voltage / have full brightness / v.v. ; so that all lamps operate independently / if one lamp blows the rest still work / you can have one light on without having them all on ; [2] (b) (i) electrons transferred ; from cloth / to balloon ; [2] (ii) like charges repel ; [1] (c) circuit breakers cut electricity to a device if too much current flows / there is a voltage surge ; [1] (d) current is low when voltage is high ; less, energy / power loss, as heat (with low current) ; [2] [Total: 8]

Page 5 Mark Scheme Syllabus Paper IGCSE – May/June 2014 0654 31 © Cambridge International Examinations 2014 6 (a) interaction between organisms ; interaction between organisms and their environment ; in a given area ; [max 2] (b) tree OR grass
insect
mongoose
serval
leopard ;; [correct organisms ; arrows correctly orientated ;] [2] (c) (i) energy lost between each trophic level ; [1] (ii) less energy available to the lions (at the top of the chain) / reverse argument ; [1] (d) (i) organism that feeds on / breaks down / gets its energy from, dead / waste (organic) matter ; [1] (ii) bacterium / fungus ; [1] (iii) all of them ; [1] (iv) recycle nutrients / owtte ; [1] [Total: 10] 7 (a) name of particle number in the nucleus proton 17 neutron 18 ;; (one for each correct row ;;) [2] (b) (i) kill microorganisms / prevent water-borne disease ; [1] (ii) chlorine + sodium iodide → sodium chloride + iodine ; [1] (c) (i) look for 23 + 35.5 (= 58.5) ; [1] (ii) look for 234 ÷ 58.5 = 4 ; [1] (iii) (look for any reference to 2:1 stoichiometry of NaCl : Cl2 ) 2 moles of Cl2 are produced ; so volume produced is 2 × 24 = 48 dm3 (unit required) ; [2] (iv) non-metals (other than H) appear at the positive electrode / anode ; chloride ions are negative / are Cl – / are anions ; chloride ions are attracted to the positive electrode / anode ; chloride ions are discharged / lose electrons (at the anode) ; [max 3] [electrode equation 2 Cl → Cl2 + 2 e– award 2 marks] [Total: 11]

Page 6 Mark Scheme Syllabus Paper IGCSE – May/June 2014 0654 31 © Cambridge International Examinations 2014 8 (a) (chemical to) thermal / heat energy ; heat water to produce steam ; (drives) turbine and generator ; reference to kinetic energy ; [max 3] (b) (i) photographic film radiation badge / dosimeter ; [1] (ii) cancer / mutation / radiation burns ; [1] (c) radio waves micro waves infrared (all three in order) ; [1] (d) (i) zero ; [1] (ii) greatest ; [1] (e) sine curve ; approx. constant amplitude and half-period ; repeated once / 2 rotations ; [3] [Total: 11] 9 (a) lipase ; [1] (b) (i) 37 ; [1] (ii) molecules / particles move slowly have less kinetic energy ; so less rate of collisions ; less successful collisions ; [max 2] (iii) denatured / destroyed by heat ; [1] (c) (i) uses less energy ; less fossil fuel / less global warming ; N S axle N S axle

Page 7 Mark Scheme Syllabus Paper IGCSE – May/June 2014 0654 31 © Cambridge International Examinations 2014 (ii) (enzyme 1 – no mark) the ECO programme works best / designed for a temperature of 30 °C ; (enzyme 1) works best / more active (at 30 °C ) than enzyme 2 / owtte ; [2] (d) add biuret solution / (alkaline) Cu(II) sulfate ; look for purple / violet colour ; [2] [Total: 11] 10 (a) (i) light waves travel faster than sound waves / v.v ; [1] (ii) as a series of compressions and rarefactions ; as longitudinal waves ; by transfer of vibrations of particles ; [max 1] (iii) sound cannot travel through a vacuum / sound requires a, medium / particles ; [1] (b) (i) 20 Hz to 20 000 Hz [1] (ii) (distance =) speed × time ; 330 × 0.05 = 16.5 (m) ; [2] (iii) v = f × λ / (f =) λ V ; frequency = 0.011 330 = 30 000 (Hz) ; [2] (c) diagram shows more cells ; diagram shows no resistor or resistor in parallel with buzzer or resistor less than 10 Ω / AVP ; [2] [Total: 10] 11 (a) muscle ; [1] (b) (i) coronary artery ; [1] (ii) death of heart tissue / cells cannot respire ; because of lack of oxygen / glucose ; [2] (c) (i) lower (overall) rate in country B / reverse ; especially for men ; 25 per year per 100 000 fewer for men / 5 fewer for women ; [max 2]

Page 8 Mark Scheme Syllabus Paper IGCSE – May/June 2014 0654 31 © Cambridge International Examinations 2014 (ii) stop smoking ; lose weight ; take (more) exercise ; eat less salt ; eat less (saturated) fat ; avoid stress ; [max 2] (iii) people in country A more (genetically) susceptible / live longer / less likely to die from other causes / AVP ; [1] [Total: 9] 12 (a) (i) metal malleable, non-metal not malleable / brittle ; metal electrical conductor, non-metal insulator ; metal heat conductor, non-metal insulator ; metal ductile, non-metal not ductile ; metal lustrous, non-metal not lustrous / dull ; metal sonorous, non-metal not sonorous ; metal high density, non-metal low density ; [max 2] (ii) (metallic) is in Group II / on left of Periodic Table / forms positive ions / 2 valence elections ; [1] (b) (i) (X / 2) reference to lowest pH ; [1] (ii) (Z / 7) pH is 7 / water is pH 7 / has a neutral pH ; [1] (iii) (Y / 12) metal oxides are alkaline / have pH greater than 7 ; [1] (c) no rust in tube 1 because water absent ; no rust in tube 4 because air / oxygen absent ; tubes 2 and 3 show that it is the oxygen from the air that is needed for rusting ; rust formed in tubes 2 and 3 because both contained, air / oxygen, and water present together / general statement that rusting requires, air / oxygen, and water present together ; [max 3] [Total: 9]