Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2013 Oct/Nov Paper 3 · Variant 2

This document consists of 28 printed pages. IB13 11_0654_32/5RP © UCLES 2013 [Turn over *7346268735* UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education CO-ORDINATED SCIENCES 0654/32 Paper 3 (Extended) October/November 2013 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 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.

2 © UCLES 2013 0654/32/O/N/13 For Examiner's Use 1 (a) Fig. 1.1 shows apparatus that can be used to test the electrical conductivity of the materials contained in beakers P, Q and R. + – aqueous sodium chloride sodium chloride crystals decane (C10H22) R Q P A low voltage d.c. supply positive electrode negative electrode Fig. 1.1 (i) Explain, in terms of protons and electrons, why a sodium ion, Na+, has a single positive electrical charge. [2] (ii) The material in beaker R is a good electrical conductor. The materials in beakers P and Q are insulators. Explain these statements in terms of ions. [3]

3 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use (iii) The material in beaker R is tested using the apparatus in Fig. 1.1. Bubbles of gas form on the surfaces of both electrodes and the pH of the solution increases. Name the gas that forms at each electrode and explain briefly why the pH increases. gas formed at the negative electrode gas formed at the positive electrode reason for the increase in pH [4] (b) Fig. 1.2 represents the structure of solid sodium chloride. sodium ion chloride ion Fig. 1.2 Explain, in terms of its structure and bonding, why sodium chloride has a very high melting point (801 °C). [3]

4 © UCLES 2013 0654/32/O/N/13 For Examiner's Use 2 (a) Fig. 2.1 shows two means of communication between Singapore and Sydney. Sydney satellite optical fibre cable Singapore Singapore Singapore Fig. 2.1 Method 1 Microwave signals are sent by satellite. Method 2 Infra-red waves carrying a signal are sent through an optical fibre cable. Fig. 2.2 shows an infra-red ray entering an optical fibre. optical fibre infra-red Fig. 2.2 The infra-red ray travels all the way through the optical fibre. (i) Explain why the infra-red ray stays inside the optical fibre. You may draw on the diagram if it helps your answer. [3]

5 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use (ii) The length of an optical fibre cable between Singapore and Sydney is 6.3 x 106 m. The speed of infra-red waves in an optical fibre is 2.1 x 108 m / s. Calculate the time taken for the signal to travel from Singapore to Sydney. State any formula that you use, show your working and state the unit of your answer. formula working unit [2] (iii) The speed at which microwaves travel through space is greater than the speed at which infra-red waves travel through an optical fibre. Suggest why the time taken by infra-red signals is less than the time taken by the microwave signals to travel from Singapore to Sydney. [1]

6 © UCLES 2013 0654/32/O/N/13 For Examiner's Use (b) Fig. 2.3 shows a demonstration of sound transmission using a bell jar. air to vacuum pump 12 1 2 3 4 5 6 7 8 9 10 11 Fig. 2.3 As the air is removed from the bell jar, the ringing sound from inside the bell jar gets quieter. When all the air has been removed, the bell cannot be heard. Explain these observations. [2]

7 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use 3 Sodium hydrogencarbonate, NaHCO3, is a white solid compound which is soluble in water. (a) A student adds some sodium hydrogencarbonate to a beaker which contains an aqueous solution of full range indicator (Universal Indicator). spatula solution of full range indicator sodium hydrogencarbonate When the sodium hydrogencarbonate dissolves, the solution changes colour from green to blue. (i) State how the pH of the mixture changes when the sodium hydrogencarbonate dissolves. [1] (ii) The student then adds excess dilute hydrochloric acid to the solution. Apart from an increase in volume, state two observations that are made when the acid is added. 1 2 [2]

8 © UCLES 2013 0654/32/O/N/13 For Examiner's Use (b) Fig. 3.1 shows apparatus a teacher uses to demonstrate the heating of sodium hydrogencarbonate. limewater u-tube cold water cobalt chloride paper large test-tube sodium hydrogencarbonate NaHCO3 heat Fig. 3.1 The solid sodium hydrogencarbonate is heated strongly for a few minutes and the following observations are made. • The cobalt chloride paper changes colour from blue to pink. • A gas bubbles out through the limewater, turning it cloudy. After the reaction a white solid remains in the large test-tube. (i) Explain how the observations show that both water and carbon dioxide are produced. [1] (ii) The teacher tells her students that • sodium hydrogencarbonate has been decomposed (broken down into simpler compounds), • the white solid which remains in the large test-tube is sodium carbonate, Na2CO3. Construct a balanced symbol equation for the decomposition of sodium hydrogencarbonate. [2]

9 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use (iii) A student places a piece of paper into a solution of sodium hydrogencarbonate. She removes the paper and allows it to dry. She notices that crystals of solid sodium hydrogencarbonate are left on the paper. sodium hydrogencarbonate solution paper dry paper covered in solid sodium hydrogencarbonate The student finds that it is now difficult to set fire to the paper. Use the results of the experiment in Fig. 3.1 to suggest why the student finds it difficult to get the paper to burn. [2] (iv) Suggest, with a reason, whether the decomposition of sodium hydrogencarbonate is an exothermic or an endothermic reaction. [2]

10 © UCLES 2013 0654/32/O/N/13 For Examiner's Use 4 Most plants have root hairs near the tips of their roots. A mutation in a plant called land cress affects the growth of its root hairs. (a) (i) Define the term mutation. [1] (ii) State one factor that increases the chance of mutation. [1] (b) The growth of root hairs in normal plants, and in plants with the mutation, is affected by the concentration of phosphate ions in the soil. Researchers grew normal and mutant land cress plants in soil with different concentrations of phosphate ions. They measured the mean number of root hairs in a small area of the roots, and also the mean length of the root hairs. Table 4.1 shows their results. Table 4.1 type of plant phosphate concentration mean number of root hairs per unit area mean length of root hairs / micrometres low 1.26 175 normal plants high 1.70 149 low 1.41 225 mutant plants high 1.85 52 (i) Describe how the addition of phosphate ions to the soil affects the root hairs in normal plants. [2] (ii) Compare the effect of adding phosphate ions to the soil for normal plants and for mutant plants. [2]

11 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use (iii) Predict and explain how a reduction in the length of its root hairs would affect the growth of a plant. [3] (c) Farmers often add fertilisers containing phosphate ions, potassium ions and nitrate ions to the soil in which they grow crops. (i) Explain why adding nitrate ions to the soil helps the crop plants to grow faster and larger. [2] (ii) Explain how careless use of fertilisers can cause harm to living organisms in rivers and lakes. [4]

12 © UCLES 2013 0654/32/O/N/13 For Examiner's Use 5 Fig. 5.1 shows a bicycle with a front light A and a rear light B powered by the same battery. B A Fig. 5.1 Fig. 5.2 shows how the lights are connected. A B Fig. 5.2 (a) The resistance of light A is 10 Ω and the resistance of light B is 5 Ω. Calculate the combined resistance of the two lights in this circuit. State the formula that you use and show your working. formula working Ω [3]

13 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use (b) The voltage supplied by the battery is 9 V. Calculate the current passing through light A. State any formula that you use, show your working and state the unit of your answer. formula working unit [2]

14 © UCLES 2013 0654/32/O/N/13 For Examiner's Use 6 Fig. 6.1 shows a fetus in the uterus just before it is born. Fig. 6.1 (a) On Fig. 6.1, use the letters A, B and C to label these parts on the diagram: A – the placenta B – amniotic fluid C – the cervix [3] (b) Describe how the placenta and umbilical cord help to supply the fetus with oxygen. [3]

15 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use 7 (a) Fluorine is one of the halogens in Group 7 of the Periodic Table. Suggest the physical state at room temperature (solid, liquid or gaseous) of fluorine. Explain your answer in terms of the relative size of fluorine molecules in comparison with those of the other halogens. physical state of fluorine explanation [2] (b) Fluorine is the most reactive element in the Periodic Table. There are only three other elements that do not react with fluorine. These elements are all found in the same group of the Periodic Table. Suggest and explain which group of the Periodic Table contains the elements that do not react with fluorine. group explanation [3] (c) In some countries, drinking water contains low concentrations of compounds containing fluoride ions. One of the compounds found in drinking water is sodium fluoride, NaF. (i) Explain briefly why, although fluorine is very reactive, it is safe to drink water that contains fluoride ions. [2]

16 © UCLES 2013 0654/32/O/N/13 For Examiner's Use (ii) A sample of drinking water contains sodium fluoride at a concentration of 0.000064 mol / dm3. Calculate the mass of sodium fluoride that must be dissolved in 10000 dm3 of water to obtain this concentration. Show your working. [3]

17 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use 8 (a) During part of a journey, a car moves 1 km and the driving force is 10 000 N. (i) Calculate the work done by the driving force. State any formula that you use, show your working and state the unit of your answer. formula working unit [2] (ii) This work is done in 100 s. Calculate the useful power output from the car’s engine during this time. State any formula that you use, show your working and state the unit of your answer. formula working unit [2]

18 © UCLES 2013 0654/32/O/N/13 For Examiner's Use (b) When the car is stationary, each of its four tyres has an area of 150 cm2 in contact with the road. The pressure exerted by the car on the road is 300 000 N / m2. Calculate the mass of the car. State any formulae that you use, show your working and state the unit of your answer. (use g = 10 N / kg) formula working unit [4] (c) The cooling system of the car uses water to remove heat energy from the hot engine. The heated water goes into the radiator. Heat energy is lost from the radiator. (i) Fig. 8.1 shows a car radiator. folded copper foil many thin copper pipes containing hot water Fig. 8.1 Explain how the features of the radiator that are shown in Fig. 8.1 increase the rate of cooling of hot water. [2]

19 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use (ii) The mass of water in the radiator is 5 kg. The specific heating capacity of water is 4200 J / kg °C. Calculate the energy released when the water in the radiator cools by 12 °C. State any formula that you use, show your working and state the unit of your answer. formula working unit [3]

20 © UCLES 2013 0654/32/O/N/13 For Examiner's Use 9 Rabbits are often kept as pets. People try to breed rabbits with unusual colours, such as himalayan colouring. Fig. 9.1 shows a rabbit with himalayan fur colour. The rabbit's fur is white with some black areas. Fig. 9.1 (a) Completely white fur and himalayan-coloured fur are produced by two alleles of a gene. When a white rabbit and a himalayan rabbit are bred together, all the offspring are white. When two of these white offspring are bred together, one quarter of their offspring are himalayan and three quarters are white. (i) Identify which allele is dominant, and suggest suitable symbols for the two alleles. dominant allele: colour produced symbol recessive allele: colour produced symbol [2] (ii) Two rabbits that are heterozygous for these alleles are crossed. Construct a genetic diagram, using your symbols from (i), to explain the results of this cross. [4]

21 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use (b) Rabbits, like humans, keep their internal body temperature constant. The body temperature of a rabbit is 38.5 °C. (i) Explain how a rabbit generates heat within its body. [2] (ii) Suggest how the fur of a rabbit helps to maintain its body temperature higher than that of its environment. [2] (iii) When himalayan rabbits are first born, they are white all over. The black colour develops gradually. The black pigment is produced by the action of an enzyme that is only active at temperatures below 25 °C. Use this information to suggest a reason for the distribution of black fur on the body of a himalayan rabbit. [2]

22 © UCLES 2013 0654/32/O/N/13 For Examiner's Use 10 Fig. 10.1 shows the structure of one molecule of a type of compound called a CFC (chlorofluorocarbon). C Cl Cl F F Fig. 10.1 (a) (i) State the number of electrons in the outer shells of chlorine and fluorine atoms. [1] (ii) State and explain briefly the number of electrons in the outer shells of the chlorine and fluorine atoms in the molecule shown in Fig. 10.1. number of electrons explanation [2] (b) Fig. 10.2 shows a cross-section through an aerosol spray can used to produce a paint spray. strong metal container paint gaseous CFC at high pressure produces a force on the paint paint spray cap is pushed down to spray surface of paint Fig. 10.2

23 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use (i) Explain, in terms of molecules, how the gaseous CFC produces a force on the surface of the paint. [2] (ii) Scientists have discovered that CFC molecules are causing damage to the atmosphere because they react with molecules of the gas ozone, O3. Describe how a molecule of ozone differs from a molecule of gaseous oxygen, O2. [1] (c) CFCs have been replaced in most aerosol spray cans by gaseous hydrocarbons such as propane and butane. (i) Complete the molecular structure diagram of one molecule of propane. C [2] (ii) Suggest one disadvantage of using hydrocarbons in aerosol spray cans. [1]

24 © UCLES 2013 0654/32/O/N/13 For Examiner's Use 11 (a) A mobile phone (cell phone) is powered by a rechargeable battery. Fig. 11.1 shows a mobile phone being charged. The charger contains a circuit which acts as a transformer. speaker screen battery microphone charger cable Fig. 11.1 Link each description in Table 11.1 with one of the labelled parts shown in Fig. 11.1. Write your answers next to the descriptions in Table 11.1 Table 11.1 description part This transforms electrical impulses into sound energy This transforms electrical energy to stored chemical energy This transforms electrical energy to light energy This reduces the mains voltage to a lower voltage. [4]

25 © UCLES 2013 0654/32/O/N/13 [Turn over For Examiner's Use (b) A simple transformer is shown in Fig. 11.2. 120 V a.c. 6 V a.c. iron core primary coil secondary coil of 40 turns input voltage output voltage Fig. 11.2 (i) Calculate the number of turns on the primary coil. State the formula that you use and show your working. formula working turns [3] (ii) State the function of the iron core in a transformer. [1] (iii) State how step-up transformers reduce the electrical energy lost in transmission through a grid from a power station to the point of use. [2]

26 © UCLES 2013 0654/32/O/N/13 For Examiner's Use (c) (i) Draw lines to show the magnetic field around the bar magnet in Fig. 11.3 S N Fig. 11.3 [2] (ii) Draw lines to show the shape of the magnetic field produced by the solenoid coil in Fig. 11.4, when an electric current passes through it. Fig. 11.4 [1]

27 © UCLES 2013 0654/32/O/N/13 For Examiner's Use 12 Cigarette smoke contains many harmful substances. (a) List four harmful components of cigarette smoke. 1 2 3 4 [2] (b) Some of the components of cigarette smoke prevent cilia from working properly. Explain how this can lead to an increase in infections of the lungs by bacteria. [2] (c) Describe the roles of white blood cells in defending the body against infections by bacteria. [3]

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 0654/32/O/N/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 October/November 2013 series 0654 CO-ORDINATED SCIENCES 0654/32 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 2013 series for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level components and some Ordinary Level components.

Page 2 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 32 © Cambridge International Examinations 2013 1 (a) (i) reference to positive charge on protons and negative charge on electrons ; reference to protons – electrons = 1 ; [2] (ii) decane is covalent / contains only molecules / no ions present ; solid NaCl ions are not mobile ; aqueous NaCl ions are mobile ; [3] (iii) hydrogen ; chlorine ; solution becomes alkaline ; because sodium hydroxide produced / OH– ion concentration increases ; because sodium hydroxide produced / OH– ion concentration increases ; because H+ ion concentration decreases ; [max 4] (b) any two of sodium and chloride ions have opposite (electrical) charge ; reference to (strong) force of attraction (between opposite charges) ; reference to giant structure / many bonds ; large amount of (heat) energy needed to break bonds ; [3] (max 1 if reference to atoms / molecules or electron and sharing / covalence) [Total: 12] 2 (a) (i) reflection ; total internal ; when angle is greater than critical angle / owtte ; [3] (ii) (time) = distance / speed ; 0.03 s ; [2] (iii) distance is less (for optical fibre / infrared) / ORA ; [1] (b) sound waves (travel by) vibration of particles / air / medium / owtte ; as the air is sucked out there are / is less particles / air / medium (to convey sound) ; no particles / no air / no medium / vacuum so (sound waves cannot pass through) ; [max 2] [Total: 8]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 32 © Cambridge International Examinations 2013 3 (a) (i) increased ; [1] (ii) colour change (blue) to red ; effervescence / (gas) bubbles produced ; [2] (b) (i) (colour change of) cobalt chloride paper shows water and (cloudy) limewater shows carbon dioxide ; [1] (ii) 2NaHCO3 → Na2CO3 + CO2 + H2O [2] (LHS and RHS for 1 mark and balanced for 1 mark) (iii) (paper covered with layer of) sodium hydrogen carbonate / owtte ; provides barrier between paper and air / oxygen ; (if paper does burn) sodium hydrogen carbonate decomposes to carbon dioxde / water which inhibit(s) burning / owtte ; [max 2] (iv) (endothermic) heat energy has to be supplied (to keep the reaction going) ; this heat is transferred to chemical energy / taken in to decompose the reactant / break bonds in reactant ; [2] [Total: 10] 4 (a) (i) a change in a gene or chromosome ; [1] (ii) ionising radiation / named ionising radiation ; [1] (b) (i) more root hairs ; shorter root hairs ; [2] (ii) increase in number in both types is the same / 0.44 more root hairs per unit area ; decrease in length is much greater in mutant plants ; [2] (iii) reduced surface area ; less able to take up water / mineral ions / named mineral ion ; (reduced water) causes reduced photosynthesis ; less glucose made ; (less) glucose used for energy / respiration ; for growth / building up large molecules / building cell walls ; less nitrate (uptake reduces protein synthesis ; less phosphate (uptake) reduces cell membrane synthesis ; less magnesium uptake reduces chlorophyll synthesis ; less potassium uptake reduces protein synthesis; [max 3]

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 32 © Cambridge International Examinations 2013 (c) (i) nitrate used to make, amino acids / proteins ; proteins needed to make new cells ; [2] (ii) reference to eutrophication ; nitrate leached into waterways / owtte ; causes algal growth to increase ; reduces light to submerged plants ; algae / shaded plants, die ; bacteria feed on dead algae / dead plants ; bacteria use oxygen (for respiration) ; which causes animals die because of lack of oxygen ; [max 4] [Total: 15] 5 (a) 1/R = 1/R1 + 1/R2/(R) = R1 × R2/R1+R2 ; correct substitution ; R = 10/3 = 3.3 Ω ; [3] (b) I = V/R ; 9/10 = 0.9 A ; [2] [Total: 5] 6 (a) A to placenta ; B to amniotic fluid ; C to cervix ; [3] (b) oxygen comes from mother's blood ; diffusion across / into placenta ; blood (vessels) in umbilical cord carry oxygen to fetus ; reference red blood cells ; reference haemoglobin / oxyhaemoglobin ; [max 3] [Total: 6] 7 (a) (gaseous / a gas) reference to smaller / lighter molecules ; reference to low attraction between molecules ; [2] (b) Group 0 / noble gases ; (gases) are inert / unreactive / very stable ; reference to complete shells / outer octet ; [3]

Page 5 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 32 © Cambridge International Examinations 2013 (c) (i) fluoride (ion) is very unreactive ; because has noble gas electron configuration / filled shells / outer electron octet ; [2] (ii) Mr sodium fluoride = 42 ; 0.000064 × 42 g 1 dm3/0.64 moles in 10000 dm3; (0.000064 × 42) × 10000 g = 26.88 or 26.9 or 27 g ; [3] [Total: 10] 8 (a) (i) work done = force × distance ; = 10000 × 1000 = 10 000 000 J ; [2] (ii) power = work/time ; 10000000/100 = 100000 W ; [2] (b) (force) = pressure × area ; calculates total area of 4 tyres ; (e.g. area = 4x150 = 600 cm2) ; converts area to m2 (e.g. 600 cm2 = 0.06 m2) ; correct substitution in formula (e.g. force = 300000 × 0.06) ; divides force by g (e.g. mass = 18000/10 = 1800 kg) ; [max 4] (c) (i) copper is a good conductor of heat ; (convection off) large surface area ; thin pipes shorter distance for conduction ; [max 2] (ii) energy = mass × specific heating capacity × temp change ; = 5 × 4200 × 12 ; = 252000 J ; [3] [Total: 13] 9 (a) (i) white allele identified as dominant and use of capital letter for its symbol ; small version of the same letter as symbol for himalayan allele ; [2] (ii) (allow whatever symbols have been chosen) (parents' genotypes) Aa and Aa ; gametes A and a from both parents, ; offspring genotypes AA, Aa, Aa and aa ; relates genotypes to phenotypes / 3 white to 1 himalayan ; [4]

Page 6 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 32 © Cambridge International Examinations 2013 (b) (i) by respiration ; oxygen combined with glucose ; chemical energy in glucose transferred to / released as heat energy ; [max 2] (ii) fur traps air ; air, acts as an insulator / poor conductor ; reduces heat loss by, convection / radiation ; [max 2] (iii) ears / paws / nose, colder than other parts of body / below 25 °C ; enzyme is active in these areas ; black pigment produced in colder areas ; [max 2] [Total: 12] 10 (a) (i) 7 ; [1] (ii) 8 ; covalent bonds exist between (halogen and carbon) atoms ; which involve sharing electrons (in pairs) / each halogen atom shares an electron with carbon ; [max 2] (b) (i) molecules in constant (random) motion ; molecules collide (repeatedly) with paint surface ; [2] (ii) ozone molecule has three oxygen atoms bonded and oxygen has two ; [1] (c) (i) ;; [2] (3 × C and 8 × H ; all C 4-valent and all H monovalent ;) (ii) flammable (so fire risk) / so adds to greenhouse gases ; [1] [Total: 9] C H H C H H C H H H H

Page 7 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 32 © Cambridge International Examinations 2013 11 (a) description part This transforms electrical impulses into sound energy speaker ; This transforms electrical energy to stored chemical energy battery ; This transforms electrical energy to light energy screen ; This reduces the mains voltage to a lower voltage. charger ; [4] (b) (i) formula e.g. Np = Vp × Ns/Vs ; correct substitution into correctly arranged formula/120 × 40/6 ; = 800 turns ; [3] (ii) transmits changing magnetic field ; [1] (iii) (high voltage) means low current ; less energy lost as heat ; [2] (c) (i) shape ; arrowheads ; [2] (ii) lines passing through coil ; [1] [Total: 13] S N

Page 8 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 32 © Cambridge International Examinations 2013 12 (a) carbon monoxide tar particulates / smoke particles nicotine 4 correct = 2 marks, 2 or 3 correct = 1 mark ;; [2] (b) mucus not swept upwards / away from lungs ; mucus accumulates in, lungs / alveoli ; bacteria breed in mucus ; [max 2] (c) phagocytes engulf bacteria ; digest them / kill them ; lymphocytes, secrete / produce, antibodies ; which attach to bacteria and help to destroy them ; [max 3] [Total: 7]