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

This document consists of 30 printed pages and 2 blank pages. DC (NH/SW) 89144/3 © UCLES 2014 [Turn over * 8 4 6 0 1 0 2 5 6 7 * CO-ORDINATED SCIENCES 0654/31 Paper 3 (Extended) October/November 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 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 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. Cambridge International Examinations Cambridge International General Certificate of Secondary Education

2 0654/31/O/N/14 © UCLES 2014 1 The method used to extract metals from their compounds depends on the reactivity of the metal. Magnesium is more reactive than iron. Most magnesium is produced industrially using electrolysis. (a) Name the industrial apparatus used to extract iron. …[1] (b) State the name or give the chemical formula of the main compound from which iron is extracted. …[1] (c) Molten iron produced by the apparatus in (a) contains sulfur as an impurity. Sulfur is removed from the molten iron by adding magnesium powder to form magnesium sulfide. Fig. 1.1 shows diagrams of a magnesium atom and a sulfur atom. magnesium sulfur Fig. 1.1 Describe the changes to the electron configurations of these atoms when magnesium sulfide is formed. … … …[2] (d) Suggest the balanced equation for the formation of magnesium sulfide. …[1]

3 0654/31/O/N/14 © UCLES 2014 [Turn over (e) Magnesium sulfide has a very high melting point. Suggest why magnesium sulfide has a very high melting point. … … … …[2]

4 0654/31/O/N/14 © UCLES 2014 2 Fig. 2.1 shows the chromosomes from the nucleus of a single cell of a human male. Fig. 2.1 (a) Fig. 2.1 shows two sets of chromosomes. State the term used to describe a cell with two sets of chromosomes. …[1] (b) (i) Complete the genetic diagram below to explain why, in a human population, equal numbers of male and female babies should be expected. parents phenotypes sex chromosomes gametes chromosomes and phenotypes of offspring female XX and and male XY male gametes female gametes … ratio of male to female [4]

5 0654/31/O/N/14 © UCLES 2014 [Turn over (ii) In fact, in all human populations, slightly more male babies are born than female babies. Suggest a possible explanation for this. … …[1] (c) In sea turtles, the sexes of the offspring are not determined by chromosomes. Instead, sex depends on the temperature at which the eggs are incubated. Fig. 2.2 shows this effect. 100 75 50 25 0 25 27 29 incubation temperature / °C 31 33 percentage of eggs that hatch into females Fig. 2.2 (i) Describe the effect of temperature on the percentage of eggs that hatch into females. … …[1] (ii) State the temperature at which equal numbers of male and female offspring are produced. …[1] (iii) Suggest why the temperature affects the percentage of eggs that hatch into females. … …[1]

6 0654/31/O/N/14 © UCLES 2014 (iv) Use the information in Fig. 2.2 to predict how global warming might affect the sea turtle population. Explain your answer. … … …[2]

7 0654/31/O/N/14 © UCLES 2014 [Turn over 3 (a) A car has two headlamps and two rear lamps. All four lamps are connected in parallel with each other across a 12 V battery. (i) Each headlamp takes a current of 4 A and each rear lamp takes a current of 0.4 A. State the total current taken by all four lamps. current = … A [1] (ii) Calculate the resistance of one of the headlamps. State the formula that you use, show your working and state the unit of your answer. formula working resistance = … unit … [3] (b) One of the headlamps of the car has a power rating of 55 W. Calculate the power of the headlamp, when the current passing through it is 4 A and the voltage across it is 12 V. State the formula that you use and show your working. formula working power = … W [2] (c) As the car drives along, the temperature of the air in the tyres increases. Use the idea of particles to explain why this will result in an increase in tyre pressure. … … … …[3]

8 0654/31/O/N/14 © UCLES 2014 4 (a) Define the term translocation. … … …[2] (b) Fig. 4.1 shows xylem vessels from the stem of a plant as seen in longitudinal section. cell wall xylem vessel Fig. 4.1 On Fig. 4.1, (i) draw an arrow to show the direction in which water flows through the xylem vessels, [1] (ii) mark with the letter X the point at which the water potential is lowest. [1] (c) Describe the mechanism by which water flows through the xylem. … … … …[3] (d) Name one other substance, apart from water, that is transported through xylem vessels. …[1]

9 0654/31/O/N/14 © UCLES 2014 [Turn over Please turn over for Question 5.

10 0654/31/O/N/14 © UCLES 2014 5 A student investigates the reactions between dilute hydrochloric acid and five substances. Fig. 5.1 shows the five substances contained in test-tubes A to E. A magnesium ribbon B zinc C copper D calcium carbonate E sodium hydrogencarbonate Fig. 5.1 She adds dilute hydrochloric acid to each tube. Her observations and temperature measurements are shown in Table 5.1. Table 5.1 test-tube observations temperature of the reactants before reaction / °C temperature of the mixture in the test-tube after a short time / °C A gas given off quickly 18 45 B gas given off slowly 18 19 C no gas produced 18 D gas given off quickly 18 20 E gas given off quickly 18 11 (a) (i) Name the gas given off when dilute hydrochloric acid is added to test-tubes A and B. …[1]

11 0654/31/O/N/14 © UCLES 2014 [Turn over (ii) The pH of the dilute hydrochloric acid before reacting is 2. Predict the pH of the solution in test-tube D after reaction. Explain your answer. prediction … explanation … … …[2] (b) Temperature changes are observed in many chemical reactions. (i) Suggest the temperature of the mixture in test-tube C after a short time. Write your answer in Table 5.1. [1] (ii) Explain your answer to (i). … …[1] (iii) Temperature changes show that the chemical potential energy of the reactants is different from that of the products. State the letter of the test-tube in which the chemical potential energy of the products is greater than that of the reactants. Explain your answer. test-tube … explanation … … …[3] (c) Suggest two possible reasons why the rate of production of gas in test-tube A is different from that in test-tube B. 1 … … 2 … …[2]

12 0654/31/O/N/14 © UCLES 2014 6 (a) Infra-red waves are part of the electromagnetic spectrum. State two properties that are the same for all electromagnetic waves. 1 … 2 …[2] (b) Infra-red waves can pass through optical fibres. (i) Fig. 6.1 shows a length of optical fibre. An infra-red ray goes in at one end and emerges at the other end. Fig. 6.1 On Fig. 6.1, use a ruler to draw the path of the ray along the optical fibre. [1] (ii) State one use of optical fibres in medicine. …[1] (c) Infra-red waves transfer energy. Fig. 6.2 shows an experiment. can A can B radiant heater lid lid d d dull black surface shiny silver surface Fig. 6.2 Two similar cans, A and B contain equal amounts of water which start off at the same temperature.

13 0654/31/O/N/14 © UCLES 2014 [Turn over Can A has a shiny silver surface and can B has a dull black surface. A thermometer is placed into each can. The cans stand on cork mats and are placed at the same distance d from a radiant heater emitting infra-red radiation. The temperature of the water is measured every minute for twelve minutes. Fig. 6.3 shows how the temperature of the water changes for the two cans. 0 2 4 6 8 10 12 40 30 20 10 0 time / minutes temperature / °C can A can B Fig. 6.3 (i) Explain why the two cans have lids, … are placed on cork mats. … [2] (ii) Explain why the temperature changes differ for the two cans. … …[1]

14 0654/31/O/N/14 © UCLES 2014 (d) A large hot meteorite falls into a lake, warming the water without causing the water to evaporate or boil. (i) Describe the difference between evaporation and boiling. … … … …[2] (ii) The meteorite is made of iron and has a mass of 32 000 kg. It has a temperature 1520 °C before it enters the lake. After it enters the lake its temperature falls to 20 °C. Calculate the thermal energy transfer, in kJ, from the hot meteorite to the water. The specific heat capacity of iron is 450 J / kg °C. State the formula that you use and show your working. formula working …kJ [3]

15 0654/31/O/N/14 © UCLES 2014 [Turn over 7 Fig. 7.1 shows the concentration of lactic acid in a muscle cell of an athlete before, during and after he has taken part in a 100 m sprint race. 0 10 20 30 40 50 60 70 time / sec concentration of lactic acid time of sprint race Fig. 7.1 (a) (i) Name the process that produces lactic acid. …[2] (ii) Give the word equation for this process. …[1] (b) State the time in Fig. 7.1 at which the lactic acid concentration is highest. …[1]

16 0654/31/O/N/14 © UCLES 2014 (c) During a sprint, the blood flow to the muscles increases. Suggest and explain the effect of this increased blood flow on (i) the rate of lactic acid production, … … …[2] (ii) the rate at which lactic acid is removed from the muscle cell. … … …[2] (d) After the sprint, the athlete is ‘out of breath’ (breathing rapidly and deeply). Explain why the athlete breathes rapidly and deeply. … … …[2] (e) Training increases the number of red blood cells in an athlete’s body. Suggest how this affects the amount of lactic acid produced when an athlete is sprinting. Explain your answer. … …[1]

17 0654/31/O/N/14 © UCLES 2014 [Turn over 8 (a) A spillage of a radioactive substance occurs in a store for radioactive materials. The activity due to normal background radiation is 100 counts per minute. After the spillage, the activity in the store rises to 900 counts per minute. (i) State the meaning of the term background radiation. … …[1] (ii) Write down the increase in activity produced by the spilled material. … counts per minute [1] (iii) The half-life of the material spilled is 20 days. The radioactive store can only be safely entered again when the total activity falls to 200 counts per minute. Calculate how many days it will take before the store can be safely entered. Show how you worked out your answer. … … … days [3] (iv) The spilled radioactive material contains a small quantity of californium-253. Write down the numbers of protons, neutrons and electrons found in an atom of californium-253. number of protons … number of neutrons … number of electrons … [1]

18 0654/31/O/N/14 © UCLES 2014 (v) Californium-253 emits α- and β- radiations. Describe the changes in the composition of the nucleus of a californium-253 atom when it emits an α-particle, … … … a β-particle. … … … [2] (b) Fig. 8.1 shows how electricity produced in a nuclear power station is transferred from the power station to the consumer. power station transformer transformer consumer transmission line Fig. 8.1 (i) Choose numbers or words from the list to complete the sentences below. You may use each number or word once, more than once or not at all. 12 230 25 000 decreases increases larger smaller step-up step-down Electricity is transmitted at … V but is supplied to consumers’ homes at … V. This requires a … transformer. The transmission voltage used makes the current …, which … the energy lost in the cable (transmission line). [2]

19 0654/31/O/N/14 © UCLES 2014 [Turn over (ii) The input power into a small transformer is 500 W and the useful output power is 450 W. Calculate the percentage efficiency of the transformer. State the formula that you use and show your working. formula working … % [2]

20 0654/31/O/N/14 © UCLES 2014 9 Fig. 9.1 shows molecules of ethane, ethene and ethanol. C H H ethane H H H H H H O H H H H H H H H C C C C C ethene ethanol Fig. 9.1 (a) (i) State and explain which of these compounds are hydrocarbons. compounds … explanation … …[2] (ii) State and explain which one of the three compounds named above is an unsaturated compound. compound … explanation … …[1] (iii) Describe what is observed when the compound in (a)(ii) reacts with a solution of bromine. … …[1] (b) (i) State two uses of ethanol. 1 … 2 … [2] (ii) In industry, ethanol is made in a chemical reaction involving ethene. Name the substance that reacts with ethene to produce ethanol. …[1] (iii) State two of the reaction conditions needed for the reaction in (b)(ii). 1 … 2 … [2]

21 0654/31/O/N/14 © UCLES 2014 [Turn over (iv) Name the type of reaction in (b)(ii). …[1] (c) Ethanol, C2H6O, reacts with a compound X to produce a mixture containing ethanoic acid, C2H4O2, which is a compound found in vinegar. H C C O H + compound X H H H H H C C O O H + other compounds H H heat Fig. 9.2 The reaction between ethanol and compound X is a redox reaction. Use the information in Fig. 9.2 to explain why X is reduced. … … …[2]

22 0654/31/O/N/14 © UCLES 2014 10 A motorcycle is driven along a straight road. Fig. 10.1 shows a speed / time graph for the motion of the motorcycle from the time the rider sees a car approaching. 14 12 10 8 6 4 2 0 0 1 2 3 4 5 6 7 8 9 10 time / s speed m / s Fig. 10.1 (a) (i) Calculate the distance the motorcycle travels while it is slowing down. Show your working. distance = …m [3] (ii) Calculate the deceleration of the motorcycle. Show your working. deceleration = … m / s2 [2]

23 0654/31/O/N/14 © UCLES 2014 [Turn over (b) The motorcycle rider notices that the sound from a car’s engine becomes louder as the car approaches and drops in pitch as the car passes. Describe these changes in terms of the frequency and amplitude of sound waves released. becomes louder … … has a lower pitch … … [2]

24 0654/31/O/N/14 © UCLES 2014 11 Fig. 11.1 shows two liver cells, as seen under a light microscope. cell membrane nucleus Fig. 11.1 (a) (i) Liver cells produce bile. Describe the role of bile in the digestion of fats. … … …[2] (ii) State two other functions of liver cells apart from bile production. 1 … 2 … [2] (b) Under a more powerful microscope, the cell membranes of the liver cells can be seen to be folded. Suggest why this is important for the functioning of the cells. … … …[2] (c) Red blood cells and plant root hair cells also have structural features that are important for their function. (i) State one function of root hair cells. …[1]

25 0654/31/O/N/14 © UCLES 2014 [Turn over (ii) State the function of a red blood cell, and give two ways in which its structure is related to its function. function … how the structure is related to the function 1 … … 2 … … [3]

26 0654/31/O/N/14 © UCLES 2014 12 (a) The Periodic Table lists the elements in order of their proton numbers. Fig. 12.1 shows the positions of the first eighteen elements. The letters are not the chemical symbols of the elements. N L M I II III IV V VI VII 0 P O Fig. 12.1 (i) State the meaning of the term proton number. … …[1] (ii) Element L has similar chemical properties to element O but different chemical properties from element M. Explain this in terms of atomic structure. … … …[2]

27 0654/31/O/N/14 © UCLES 2014 [Turn over (b) A student attempted to draw a dot-and-cross diagram for a molecule of carbon dioxide. Fig. 12.2 shows the diagram he produced, but it is incorrect. C O C Fig. 12.2 Draw the correct dot-and-cross diagram for a molecule of carbon dioxide in the space below. [3]

28 0654/31/O/N/14 © UCLES 2014 (c) A student investigates how much carbon dioxide gas is contained in a carbonated (fizzy) drink. He measures the mass of a full bottle of fizzy drink. cap balance bottle containing fizzy drink He shakes the bottle. He releases the carbon dioxide by carefully unscrewing the cap. He measures the mass of the bottle and cap, and liquid without the carbon dioxide. His results are shown in Table 12.1. Table 12.1 mass of bottle filled with fizzy drink / g mass of bottle and cap, and liquid without carbon dioxide / g volume of the liquid / cm3 476.2 474.0 454.0 (i) State the mass of carbon dioxide that is released from the fizzy drink. …[1] (ii) Calculate the number of moles of carbon dioxide released from the fizzy drink. Show your working. …[2]

29 0654/31/O/N/14 © UCLES 2014 (iii) Calculate the concentration of carbon dioxide in the original fizzy drink. State your answer in units of mol / dm3. Show your working. … mol / dm3 [2]

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32 0654/31/O/N/14 © UCLES 2014 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.). 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.

® IGCSE is the registered trademark of Cambridge International Examinations. CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International General Certificate of Secondary Education MARK SCHEME for the October/November 2014 series 0654 CO-ORDINATED SCIENCES 0654/31 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 October/November 2014 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 – October/November 2014 0654 31 © Cambridge International Examinations 2014 1 (a) blast furnace ; [1] (b) iron oxide / iron(III) oxide / Fe2O3 ; [1] (c) magnesium loses electrons and sulfur gains electrons ; reference to loss or gain of two electrons ; reference to acquisition of complete outer shells ; [max 2] (d) Mg + S → MgS ; [1] (e) it is an ionic compound ; strong attraction between ions / opposite charges attract (strongly) ; much (thermal) energy needed to separate ions ; [max 2] [Total: 7] 2 (a) diploid ; [1] (b) (i) gametes correctly shown: X, (X), X, Y ; offspring chromosomes correctly shown ; gametes shown correctly in punnet square ; 1:1 / 2:2 or 50 / 50 ; [4] parents phenotypes sex chromosomes gametes chromosomes and phenotypes of offspring female XX and male XY and male gametes female gametes ratio … X X X Y X X X Y XX female XY male XX female XY male 1 : 1

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0654 31 © Cambridge International Examinations 2014 (ii) X sperm less viable / swim slower / AVP / random chance ; [1] (c) (i) as temperature increases percentage of females increases ; [1] (ii) 29 (°C) ; [1] (iii) increased temperature activates, genes / enzymes, / kills males / AVP ; [1] (iv) more females would hatch / ORA ; reduced fertility of the population / owtte ; [2] [Total: 11] 3 (a) (i) 8.8 (A) ; [1] (ii) R = I V ; = 4 12 = 3 ; Ω / ohms ; [3] (b) (P =) V x I ; = 12 x 4 = 48 (W) ; [2] (c) (as temperature increases) kinetic energy / velocity of molecules / particles / atoms increases ; increased force / energy of collisions ; increased frequency of collisions ; (collisions with) walls / surface of tyre ; [max 3] [Total: 9] 4 (a) movement of sucrose / sugars / amino acids ; in phloem ; [2] (b) (i) arrow drawn going upwards, in xylem vessel ; [1] (ii) X at / near the top of the diagram ; [1] (c) transpiration / evaporation (from leaves) ; causing a tension / ‘pull’ (in the xylem) ; creates water potential gradient ; and water molecules are cohesive ; [max 3] (d) nitrate / magnesium / any correct named mineral ion ; [1] [Total: 8]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0654 31 © Cambridge International Examinations 2014 5 (a) (i) hydrogen ; [1] (ii) greater than 2 but less than 7 ; some of the acid has reacted / been used up / acid concentration is lower / lower concentration means higher pH ; [2] (b) (i) 18 (°C) ; [1] (ii) copper does not react with dilute acid / there is no reaction ; [1] (iii) E ; thermal energy has been converted into chemical energy / reference to takes in heat energy / thermal energy from the surroundings ; shown by reaction being endothermic / temperature decrease ; [3] (c) [answers must relate answers to the test-tubes or materials] in tube A the metal has ‘different’ surface area / greater degree of division ; (metal in) tube A magnesium is more reactive than zinc / or metal in A more reactive ; reaction in A is more exothermic OR higher temperature produces higher rate ; [max 2] [Total: 10] 6 (a) travel at same speed (3 x 108 m / s) ; travel in a vacuum / ORA ; transverse waves ; [2 max] (b) (i) reflection shown and angles approximately correct ; [1] (ii) e.g. (non-surgical) internal investigations / optical fibres passed into / inside body ; [1] (c) (i) lid – prevent (heat loss) by convection / evaporation ; cork mat – is an insulator / prevents conduction ; [2] (ii) can B / dull / black surfaces are better absorbers; OR can A / shiny / silver surfaces are worse absorbers (reflect heat) ; [max 1] (d) (i) evaporation occurs at any temperature / boiling only occurs at the boiling point of a liquid ; evaporation – only most energetic particles can escape from surface / boiling – all particles have enough energy to escape ; [2] (ii) (thermal energy transferred / heat) = mc∆T ; = 32000 × 450 × 1500 ; = 2.16 × 1010 J = 2.16 × 107 kJ ; [3] [Total: 12]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0654 31 © Cambridge International Examinations 2014 7 (a) (i) anaerobic ; respiration ; [2] (ii) glucose → lactic acid ; [1] (b) 32 (seconds) ; [1] (c) (i) lactic acid production is slower / decreases ; because blood supplies more oxygen / less need for anaerobic respiration / more aerobic respiration ; [2] (ii) lactic acid removed faster ; because more oxygen to convert it to CO2 / more (lactic acid) is oxidised etc. ; [2] (d) to absorb more oxygen (into blood / cells) ; idea of oxygen debt ; the extra oxygen is being used for breakdown of lactic acid / oxidises the lactic acid ; [max 2] (e) produce less, (no mark) because better oxygen supply ; [1] [Total: 11] 8 (a) (i) (ionising) radiation constantly present in the natural environment / surroundings of the Earth (which is emitted by natural and artificial sources) ; [1] (ii) 800 (cpm) ; [1] (iii) evidence of using background radiation 100, e.g. starting at 800 (max 2 marks if this not shown) ; 3 half-lives (or correct use of 3 in the calculation) ; 60 (days) ; [3] (iv) number of protons: 98 number of neutrons: 155 number of electrons: 98 ; [1] (v) α - loses 2 protons and 2 neutrons ; β - proton gain, neutron loss ; [2] (b) (i) 25 000 230 step down smaller (allow decreases) decreases (allow smaller) (all five correct: 2 marks, four correct: 1 mark) ;; [max 2]

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0654 31 © Cambridge International Examinations 2014 (ii) (efficiency =) input energy output energy ; = 100 × 500 450 = 90% ; [2] [Total: 12] 9 (a) (i) ethane and ethene ; contain only hydrogen and carbon ; [2] (ii) (ethene) contains (C to C) double bond / does not contain maximum possible hydrogen ; [1] (iii) orange / brown solution decolourised ; (reject red) [1] (b) (i) any two from: solvent / fuel / in drinks / other correct ;; [max 2] (ii) water ; (allow water vapour / steam) [1] (iii) moderate / high temperature / 300 – 350 °C ; high pressure / 60 – 70 (atmospheres) ; catalyst / phosphoric(V) acid ; [max 2] (iv) addition (reaction) ; [1] (c) X, loses oxygen / gains hydrogen, (and so is reduced) ; ethanol gains oxygen / loses hydrogen, (and so is oxidised) ; idea of, if one reactant is oxidised the other must be reduced ; [max 2] [Total: 12] 10 (a) (i) area under graph (triangle and rectangle) ; (1/2 × 5 × 10) + 10 ; = 35 (m) ; [3] (ii) (deceleration / acceleration =) change in speed / change in time (or working) ; = 2 (m / s2) ; [2] (b) becomes louder – amplitude increases ; has a lower pitch – frequency decreases ; [2] [Total: 7]

Page 7 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0654 31 © Cambridge International Examinations 2014 11 (a) (i) emulsifies ; increases surface area ; so, faster digestion ; [max 2] (ii) stores glycogen ; controls blood glucose / sugar levels ; breaks down poisons / alcohol ; destroys hormones ; produce urea / deamination ; remove old red blood cells ; AVP ; [max 2] (b) increased surface area ; for uptake / absorb of substance(s) ; [2] (c) (i) absorption of water / mineral ions ; [1] (ii) oxygen transport ; contains haemoglobin, to carry oxygen ; no nucleus, so more room for haemoglobin / oxygen ; biconcave shape, so flexible / large surface area ; [max 3] [Total: 10] 12 (a) (i) number of protons in atom / nucleus ; [1] (ii) idea that L and O in same group / properties similar within groups ; atoms of L and O have same number of outer electrons / L and M have different numbers of outer electrons / or statement of number of electrons in outer shells ; chemical properties related to number of outer electrons ; [max 2] (b) symbols correct ; have 8 electrons in all outer shells ; two shared pairs in both bonds ; [3] (c) (i) 476.2 – 474.0 or 2.2 g (unit required) ; [1] (ii) Mr CO2 = 44 ; number of moles = 2.2 ÷ 44 = 0.05 ; (allow ecf from (i)) ; [2] (iii) (express volume of drink in dm3 =) 0.454 (dm3) ; concentration = 0.05 ÷ 0.454 = 0.11 (mol / dm3) ; (allow ecf) [2] [Total: 11]