Cambridge IGCSE Science - Combined 0653 — 2013 Oct/Nov Paper 3 · Variant 2

This document consists of 20 printed pages. IB13 11_0653_32/5RP © UCLES 2013 [Turn over *2564437090* UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/32 Paper 3 (Extended) October/November 2013 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units. A copy of the Periodic Table is printed on page 20. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. www.XtremePapers.com

2 © UCLES 2013 0653/32/O/N/13 For Examiner's Use 1 Fig. 1.1 shows apparatus that can be used to test the electrical conductivity of materials contained in beakers P, Q and R. + – aqueous copper chloride copper chloride crystals decane (C10H22) R Q P A low voltage d.c. supply positive electrode negative electrode Fig. 1.1 (a) 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 0653/32/O/N/13 [Turn over For Examiner's Use (b) The material in beaker R is tested using the apparatus in Fig. 1.1. Bubbles of gas form on the surface of one of the electrodes. (i) Name the gas that forms. [1] (ii) A layer of an orange solid is formed on the other electrode. Explain, in terms of ions, electrons and atoms, what is happening at the surface of this electrode. [3] (c) Sodium chloride is a hard, crystalline solid at room temperature. Fig. 1.2 shows a diagram that represents the structure of sodium chloride. sodium ion chloride ion Fig. 1.2 Explain, in terms of forces, why sodium and chloride particles stay strongly bonded. [2]

4 © UCLES 2013 0653/32/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 0653/32/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 0653/32/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 0653/32/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 0653/32/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 is heated strongly for a few minutes. • 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 0653/32/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 0653/32/O/N/13 For Examiner's Use 4 (a) Most plants have root hairs near the tips of their roots. Researchers grew two different types of crop plants, A and B, 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 A high 1.70 149 low 1.41 225 B high 1.85 52 (i) Describe how the addition of phosphate ions to the soil affects the root hairs in Type A plants. [2] (ii) Compare the effect of adding phosphate ions to the soil for type A plants and type B plants. [2]

11 © UCLES 2013 0653/32/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] (b) Farmers often add fertilisers containing phosphate ions, potassium ions and nitrate ions to the soil in which they grow crops. Explain how careless use of fertilisers can cause harm to living organisms in rivers and lakes. [4]

12 © UCLES 2013 0653/32/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) State the name given to this type of circuit arrangement. [1]

13 © UCLES 2013 0653/32/O/N/13 [Turn over For Examiner's Use (b) (i) 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] (ii) 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] (c) The bicycle was made from a block of aluminium alloy of mass 9000 g and volume 3000 cm3. Calculate the density of aluminium in g / cm3. State the formula that you use and show your working. formula working g / cm3 [2]

14 © UCLES 2013 0653/32/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 0653/32/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) Fig. 7.1 shows the structure of one molecule of a type of compound called a CFC (chlorofluorocarbon). C Cl Cl F F Fig. 7.1 (i) Name the type of chemical bonds that hold the atoms together in the molecule in Fig. 7.1. Explain your answer briefly. type of bonding explanation [2] (ii) State the number of electrons in the outer shells of chlorine and fluorine atoms. [1] (iii) State and explain briefly the number of electrons in the outer shells of the chlorine and fluorine atoms in the molecule shown in Fig. 7.1. number of electrons explanation [2]

16 © UCLES 2013 0653/32/O/N/13 For Examiner's Use 8 (a) Fig. 8.1 shows a car moving along a road. (i) Draw and label arrows on Fig. 8.1 to show the directions of the driving and friction forces acting on the car. [1] Fig. 8.1 (ii) The driving and friction forces are balanced. Explain what is meant by the phrase forces are balanced. [1] (iii) Describe the movement of the car when these forces are balanced. [1] (iv) The car accelerates. Compare the relative sizes of the driving and friction forces as the speed increases. [1] (b) (i) During part of a journey, a car moves 1 km and the driving force is 10 000 N. 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]

17 © UCLES 2013 0653/32/O/N/13 [Turn over For Examiner's Use (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] (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) Name the part of the electromagnetic spectrum that is involved in the transfer of heat by radiation. [1] (ii) Fig. 8.2 shows a car radiator. folded copper foil many thin copper pipes containing hot water Fig. 8.2 Explain how the features of the radiator that are shown in Fig. 8.2 increase the rate of cooling of hot water. [2]

18 © UCLES 2013 0653/32/O/N/13 For Examiner's Use 9 Fig. 9.1 shows an alveolus and a blood capillary in the lungs. 1 2 air capillary Fig. 9.1 (a) The arrows labelled 1 and 2 show the direction of diffusion of two gases. (i) Name the gases. gas 1 gas 2 [2] (ii) Define the term diffusion. [2] (iii) Explain how the structure of the wall of the capillary and the wall of the alveolus help diffusion of these gases to take place efficiently. [2]

19 © UCLES 2013 0653/32/O/N/13 For Examiner's Use (b) Cigarette smoke contains many harmful substances. (i) List four harmful components of cigarette smoke. 1 2 3 4 [2] (ii) 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]

20 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. © UCLES 2013 0653/32/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 0653 COMBINED SCIENCE 0653/32 Paper 3 (Extended Theory), maximum raw mark 80 This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the October/November 2013 series for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level components and some Ordinary Level components. www.XtremePapers.com

Page 2 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0653 32 © Cambridge International Examinations 2013 1 (a) P decane covalent molecules only / no ions present ; Q solid copper chloride ions are not mobile ; R aqueous copper chloride ions are mobile ; (may refer to ions as charge carriers) (max 2 if suggested that immobile ions exist in decane) [3] (b) (i) chlorine ; [1] (ii) copper is / copper atoms are forming / copper ions are being attracted ; copper ions are gaining electrons ; copper ions are being discharged / (gaining) two (electrons) each ; [3] (c) sodium and chloride ions have opposite (electrical) charge ; reference to force of attraction (between opposite charges) ; [max 2] [Total: 9] 2 (a) (i) reflection ; total internal ; when angle (of incidence ) is greater than critical angle ; [3] (ii) time = distance/speed ; 0.03 s ; [2] (iii) distance is less (for optical fibre) ; [1] (b) sound waves need a medium ; as the air is sucked out there is less of a medium to convey the sound wave ; no air means sound waves cannot pass through ; [max 2] [Total: 8]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0653 32 © Cambridge International Examinations 2013 3 (a) (i) increased / numerical example ; [1] (ii) colour change (blue) to red ; effervescence / (gas) bubbles produced ; [2] (b) (i) colour change of cobalt chloride paper shows water and limewater reaction shows carbon dioxide ; (test results are not required) [1] (ii) 2NaHCO3 → Na2CO3 + CO2 + H2O ; ; [2] (LHS RHS; and balanced;) (iii) sodium hydrogencarbonate provides barrier between paper and and air/oxygen ;(if paper does burn) sodium hydrogencarbonate decomposes / releases carbon dioxide / water ; carbon dioxide / water inhibits burning / owtte ; [max 2] (iv) (endothermic) heat energy supplied (to keep the reaction going) ; heat is transferred to chemical energy ; heat is used to decompose (the reactant) /to break bonds in the reactant ; [max 2] [Total: 10] 4 (a) (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 / percentage increase is different ; decrease in length is much greater in type B plants ; [2] (iii) reduced surface area ; less able to take up water ; so less water available for photosynthesis ; less able to take up, mineral ions / named ion ; less able to take up nitrates to form proteins ; plant may wilt ; because water loss greater than water uptake ; [max 3] (b) ref. to eutrophication ; nitrate leached into waterways ; causes algal growth to increase ; reduces photosynthesis / light available for submerged plants ; submerged plants / algae die ; bacteria feed on dead plants / algae ; bacteria use oxygen (for respiration) ; which causes animals to die because of lack of oxygen ; [max 4] [Total: 11]

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0653 32 © Cambridge International Examinations 2013 5 (a) parallel ; [1] (b) (i) 1/R1 + 1/R2 = 1/R ; correct substitution ; R = 10/3 = 3.3 Ω ; [3] (ii) I = V/R ; 9/10 = 0.9 A ; [2] (c) density = mass/volume ; = 9000/3000 = 3.0 g/cm3 ; [2] [Total: 8] 6 (a) A to placenta ; B to amniotic fluid ; C to cervix ; [3] (b) oxygen comes from mother('s blood) ; ref. red blood cells ; ref. haemoglobin ; diffusion across placenta ; blood (vessels) in umbilical cord carry oxygen to foetus ; [max 3] [Total: 6] 7 (a) gaseous / a gas ; reference to smaller / lighter molecules ; reference to low attraction between molecules ; [max 2] (b) (i) covalent ; non-metallic elements joined / it is a molecule ; [2] (ii) 7 ; [1] (iii) 8 ; each halogen atom shares an electron (pair) with carbon ; reference to the completion of the outer shell of the halogen ; [max 2] [Total: 7]

Page 5 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0653 32 © Cambridge International Examinations 2013 8 (a) (i) driving force forwards and friction forces backwards ; [1] (ii) equal and opposite ; [1] (iii) constant speed ; [1] (iv) driving force is greater than friction force ; [1] (b) (i) work done = F × D ; = 10000 × 1000 = 10000000 J ; [2] (ii) power = work/time ; 10000000/100 = 100000 ; [2] (c) (i) infra-red ; [1] (ii) copper is a good conductor of heat ; (convection off) large surface area ; thin pipes means shorter distance for conduction ; [2] [Total: 11] 9 (a) (i) 1 carbon dioxide ; 2 oxygen ; [2] (ii) movement of molecules ; from region of high concentration to low concentration / down a concentration gradient ; reference to random movement (of molecules) ; [2] (max 1 if implication that a membrane is required) (iii) thin / only one cell thick ; reduces diffusion distance ; [2] (b) (i) carbon monoxide tar particulates / smoke particles nicotine ; ; [2] (any two for one mark) (ii) mucus not swept upwards / away from lungs / details of the normal functioning of cilia and the fact that this is impaired ; mucus accumulates in, lungs / alveoli ; bacteria breed / accumulate in mucus ; [max 2] [Total: 10]