Cambridge IGCSE Science - Combined 0653 — 2016 Oct/Nov Paper 3 · Variant 1

This document consists of 23 printed pages and 1 blank page. DC (LEG/SW) 122366/3 © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 9 9 3 9 6 9 2 7 6 7 * COMBINED SCIENCE 0653/31 Paper 3 (Extended) October/November 2016 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 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 24. 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 0653/31/O/N/16 © UCLES 2016 1 Fig. 1.1 shows a solar-powered pump used to fill a water trough from a well on a farm. Animals in a field on the farm drink from the trough. solar panels electric cable water pipe water trough water pump well electric motor Fig. 1.1 The solar panels use sunlight to generate electricity. The motor uses the electricity to drive the pump. The pump moves water from the well to the water trough. (a) (i) Complete the sequence of energy transformations that takes place as the water pipe is filled when the pump is switched on. from … energy electrical to … energy to … energy potential to … energy [2] (ii) The pipe from the pump to the trough is 9 m long. When the pump starts, it takes 12 s for water to move from the well to the trough. Calculate the average speed of the water through the pipe. speed = … m / s [1]

3 0653/31/O/N/16 © UCLES 2016 [Turn over (b) Fig. 1.2 shows a speed / time graph for one water molecule as it moves from the well through the pipe to the trough. 0 0 0.5 speed m / s time / s 1.0 2 4 6 8 10 12 Fig. 1.2 (i) State the maximum speed of the water molecule through the pipe. speed = … m / s [1] (ii) Use Fig. 1.2 to describe how the motion of the molecule between 0 s and 4 s differs from its motion between 10 s and 12 s. … … … …[2] (c) The water level in the well is 6 m below the water in the trough. (i) Calculate the work done in raising 10 kg of water from the well to the trough. (gravitational field strength, g = 10 N / kg) State any formula you use and show your working. formula working work done = … J [2]

4 0653/31/O/N/16 © UCLES 2016 (ii) When the pump is working steadily, it takes 2 minutes to pump 10 kg of water from the well into the trough. Use your answer to (i) to calculate the output power of the pump. State any formula you use and show your working. formula working power = … W [2]

5 0653/31/O/N/16 © UCLES 2016 [Turn over Please turn over for Question 2.

6 0653/31/O/N/16 © UCLES 2016 2 An atom of sodium has the symbol shown. 23 11Na (a) Deduce the number of neutrons and the number of electrons in an atom of sodium. neutrons … electrons … [2] (b) State the electronic structure of the sodium atom. … [1] (c) Describe the relationship between the electronic structure of the sodium atom and the number of its group in the Periodic Table. … …[1] (d) The equation for the reaction between sodium and oxygen is 4Na + O2 2Na2O (i) Describe, in terms of electrons, the formation of a sodium ion from a sodium atom. …[1] (ii) Use the Periodic Table on page 24 to identify the element which has atoms with the same electronic structure as a sodium ion. …[1]

7 0653/31/O/N/16 © UCLES 2016 [Turn over (e) All of the Group I metals are solid at 20 °C. Table 2.1 shows the melting points of some of the Group I metals. Table 2.1 metal melting point / °C Li Na 98 K 64 Rb 39 Cs Complete Table 2.1 by suggesting the melting points of lithium, Li, and caesium, Cs. [2] (f) Solid sodium chloride, NaCl, contains sodium ions, Na+, and chloride ions, Cl –. observations 1. Sodium ions cannot be separated from chloride ions in solid sodium chloride by any simple separation method. 2. An aqueous solution of sodium chloride can be separated into sodium chloride and water by the process of evaporation. Explain these observations. observation 1 … … … observation 2 … … …[2]

8 0653/31/O/N/16 © UCLES 2016 3 Some cress seeds are placed on damp cotton wool in a dish. They are left to germinate in a light-proof box for a few days. damp cotton wool cress seed light-proof box at the start after a few days Fig. 3.1 (a) Fig. 3.1 shows that the seedlings grow directly upwards. Name this response. …[1] (b) The dish of seedlings is removed from the box and lit from one side. Fig. 3.2 shows what happens. seedlings immediately after removal light seedlings after a few hours light Fig. 3.2 Explain in detail how hormones in the seedlings cause the response shown in Fig. 3.2. You may use a diagram to illustrate your answer. … … … … …[3]

9 0653/31/O/N/16 © UCLES 2016 [Turn over (c) A student thinks that the germination of seeds might be affected by acid rain. The student has five dishes each containing 20 seeds. He waters them with solutions that have a range of pH values. Table 3.1 shows the results after a few days. Table 3.1 pH of solution number of seeds that germinate 3 1 4 3 5 3 6 14 7 16 (i) Describe the effect of pH on the germination of the seeds. … … … … …[2] (ii) Explain why the germination of seeds is affected by pH. … … …[1] (iii) The pH of acid rain is usually between pH 4 and 5. Calculate the percentage germination in this pH range. answer = … % [1]

10 0653/31/O/N/16 © UCLES 2016 (d) (i) Describe how the activities of humans cause acid rain. … … … … …[2] (ii) Suggest how acid rain affects the productivity of farms which grow crops. Explain your answer. … …[1]

11 0653/31/O/N/16 © UCLES 2016 [Turn over Please turn over for Question 4.

12 0653/31/O/N/16 © UCLES 2016 4 There is a water trough in a field for animals to drink from. On a hot day, the level of the water in the trough drops even when there are no animals drinking from it. (a) (i) Explain in terms of the energy and movement of water molecules why the level of water goes down in the trough on a hot day. … … … … … …[3] (ii) The thermal energy causing the process in (i) is provided by the Sun. Suggest one way in which the loss of water from the trough could be reduced without placing a lid on the trough. … …[1] (b) Fig. 4.1 shows the farmer looking at a stick lying in the water trough. stick trough water Fig. 4.1 The farmer says that the stick looks bent where it goes into the water. (i) Name the property of light that causes the stick to look bent. …[1] (ii) On Fig. 4.1, draw a ray diagram using two rays from the bottom of the stick to show why the stick appears bent when the farmer looks at it from the side. [3]

13 0653/31/O/N/16 © UCLES 2016 [Turn over (c) The farmer speaks to someone on his cell phone (mobile phone). Identify and describe the two different types of wave that enable two people to speak to each other using cell phones. … … … … … …[3]

14 0653/31/O/N/16 © UCLES 2016 5 (a) Iron is extracted in the blast furnace, as shown in Fig. 5.1. raw materials including iron oxide and carbon hot air molten iron Fe2O3 + …CO …Fe + …CO2 CO2 + C … … C + O2 Fig. 5.1 (i) Complete and balance the equations in Fig. 5.1. [3] (ii) The three equations in Fig. 5.1 represent redox reactions. Identify one substance in these equations which is reduced. Explain your answer briefly. substance … explanation … …[2] (b) Aluminium is extracted from aluminium oxide, Al2O3, by the process of electrolysis, as shown in Fig. 5.2. + carbon anode carbon cathode molten aluminium molten electrolyte containing aluminium oxide – Fig. 5.2 (i) Suggest why aluminium cannot be extracted from aluminium oxide by heating with carbon in a blast furnace. … …[1]

15 0653/31/O/N/16 © UCLES 2016 [Turn over (ii) The electrolysis of aluminium oxide does not occur if it is solid. Explain, in terms of the ions present, why the electrolyte must be molten. … … …[1] (iii) Describe briefly, in terms of electrons, what happens to the aluminium ions, Al3+, and the oxide ions, O2–, when aluminium and oxygen are formed during electrolysis. aluminium ions … … oxide ions … …[1] (c) (i) Suggest why aluminium alloys, rather than iron alloys, are used in aircraft construction. …[1] (ii) Suggest why aluminium alloys, rather than pure aluminium, are used in aircraft construction. …[1]

16 0653/31/O/N/16 © UCLES 2016 6 (a) Microorganisms are added to milk to make yoghurt. They use the nutrients in the milk to make lactic acid. The lactic acid causes the milk to thicken. Fig. 6.1 shows how the lactic acid production of a microorganism varies with temperature. 30 rate of lactic acid production temperature / °C 35 40 45 50 55 60 Fig. 6.1 (i) State the optimum temperature for lactic acid production by this microorganism. …[1] (ii) Describe evidence from Fig. 6.1 that shows that lactic acid production depends on enzyme action in the microorganism. … … …[1] (b) Yoghurt can be made from different types of milk. Table 6.1 shows some of the substances found in two different types of milk. Table 6.1 substance milk A / g per 100 cm3 milk B / g per 100 cm3 protein 3.4 7.2 fat 3.6 0.1 carbohydrate 4.7 4.9 calcium (mineral salt) 0.1 0.1 fibre none none

17 0653/31/O/N/16 © UCLES 2016 [Turn over (i) Milk B contains more protein than milk A. State why the body needs protein. … …[1] (ii) A balanced diet contains five nutrient groups, as well as fibre and water. Name the nutrient group, present in milk, which is not listed in Table 6.1. … Describe the importance of including this nutrient group in a balanced diet. … … … … [2] (iii) Suggest which type of milk, A or B, would be a healthy choice for someone who does not wish to develop coronary heart disease. Explain your answer. type of milk … explanation … … … [1] (c) Sometimes fresh fruit is added to yoghurt in the final stages of manufacture. This improves the yoghurt by adding fibre. Explain the importance of fibre in the diet. … …[1]

18 0653/31/O/N/16 © UCLES 2016 7 Fig. 7.1 shows a circuit diagram for a solar-powered electric motor. M solar cell electric motor Fig. 7.1 (a) When the motor is turning, the potential difference (p.d.) across the motor is 1.5 V, across the lamp is 0.5 V, and across the variable resistor is 0.6 V. (i) Calculate the p.d. across the solar cell. p.d. across cell = … V [1] (ii) The current in the circuit is 0.3 A. Calculate the resistance of the lamp in the circuit. State the formula you use and show your working. formula working resistance = … Ω [2]

19 0653/31/O/N/16 © UCLES 2016 [Turn over (iii) Calculate the power output of the solar cell. State any formula you use and show your working. formula working power = … W [2] (b) The purpose of the lamp in the circuit in Fig. 7.1 is to indicate that the motor is working. Explain why the lamp is connected in series and not in parallel with the motor. … …[1]

20 0653/31/O/N/16 © UCLES 2016 8 Fig. 8.1 shows fractional distillation and catalytic cracking at an oil refinery. L strong heat catalytic cracker fractional distillation column Fig. 8.1 (a) (i) Name the raw material that enters the fractional distillation column at L. …[1] (ii) State the physical property which enables the different molecules to be separated during fractional distillation. …[1] (b) Cracking molecules of the hydrocarbon C20H42 produces a mixture of compounds, as shown below. C20H42 3C2H4 + 2X + C8H18 (i) Deduce the formula of compound X. … [1] (ii) Name the compound with the formula C2H4. …[1] (iii) Describe a simple chemical test that can distinguish octane, C8H18, from C2H4. Give the results for both compounds. test … … C8H18 result … C2H4 result … [2]

21 0653/31/O/N/16 © UCLES 2016 [Turn over (c) Give the word equation for the complete combustion of octane. octane + + [1] Please turn over for Question 9.

22 0653/31/O/N/16 © UCLES 2016 9 Fig. 9.1 shows a fetus shortly before it is born. X Fig. 9.1 (a) Complete the sentences below using the words or phrases provided. You may use each word or phrase once, more than once or not at all. amnion an artery a vein carbon dioxide oxygen placenta umbilical cord Structure X is the … . It contains … which carries blood to the … to collect … for the growing fetus. [4] (b) (i) Describe two ways in which HIV can be transmitted. 1. … 2. …[2] (ii) Describe how the immune system is affected by HIV/AIDS. … … …[2]

23 0653/31/O/N/16 © UCLES 2016 BLANK PAGE

24 0653/31/O/N/16 © UCLES 2016 To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series. Group The Periodic Table of Elements 1 H hydrogen 1 2 He helium 4 I II III IV V VI VII VIII 3 Li lithium 7 4 Be beryllium 9 atomic number atomic symbol Key name relative atomic mass 11 Na sodium 23 12 Mg magnesium 24 19 K potassium 39 20 Ca calcium 40 37 Rb rubidium 85 38 Sr strontium 88 55 Cs caesium 133 56 Ba barium 137 87 Fr francium – 88 Ra radium – 5 B boron 11 13 Al aluminium 27 31 Ga gallium 70 49 In indium 115 81 Tl thallium 204 6 C carbon 12 14 Si silicon 28 32 Ge germanium 73 50 Sn tin 119 82 Pb lead 207 22 Ti titanium 48 40 Zr zirconium 91 72 Hf hafnium 178 104 Rf rutherfordium – 23 V vanadium 51 41 Nb niobium 93 73 Ta tantalum 181 105 Db dubnium – 24 Cr chromium 52 42 Mo molybdenum 96 74 W tungsten 184 106 Sg seaborgium – 25 Mn manganese 55 43 Tc technetium – 75 Re rhenium 186 107 Bh bohrium – 26 Fe iron 56 44 Ru ruthenium 101 76 Os osmium 190 108 Hs hassium – 27 Co cobalt 59 45 Rh rhodium 103 77 Ir iridium 192 109 Mt meitnerium – 28 Ni nickel 59 46 Pd palladium 106 78 Pt platinum 195 110 Ds darmstadtium – 29 Cu copper 64 47 Ag silver 108 79 Au gold 197 111 Rg roentgenium – 30 Zn zinc 65 48 Cd cadmium 112 80 Hg mercury 201 112 Cn copernicium – 114 Fl flerovium – 116 Lv livermorium – 7 N nitrogen 14 15 P phosphorus 31 33 As arsenic 75 51 Sb antimony 122 83 Bi bismuth 209 8 O oxygen 16 16 S sulfur 32 34 Se selenium 79 52 Te tellurium 128 84 Po polonium – 9 F fluorine 19 17 Cl chlorine 35.5 35 Br bromine 80 53 I iodine 127 85 At astatine – 10 Ne neon 20 18 Ar argon 40 36 Kr krypton 84 54 Xe xenon 131 86 Rn radon – 21 Sc scandium 45 39 Y yttrium 89 57–71 lanthanoids 89–103 actinoids 57 La lanthanum 139 89 Ac lanthanoids actinoids The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.) actinium – 58 Ce cerium 140 90 Th thorium 232 59 Pr praseodymium 141 91 Pa protactinium 231 60 Nd neodymium 144 92 U uranium 238 61 Pm promethium – 93 Np neptunium – 62 Sm samarium 150 94 Pu plutonium – 63 Eu europium 152 95 Am americium – 64 Gd gadolinium 157 96 Cm curium – 65 Tb terbium 159 97 Bk berkelium – 66 Dy dysprosium 163 98 Cf californium – 67 Ho holmium 165 99 Es einsteinium – 68 Er erbium 167 100 Fm fermium – 69 Tm thulium 169 101 Md mendelevium – 70 Yb ytterbium 173 102 No nobelium – 71 Lu lutetium 175 103 Lr lawrencium –

® IGCSE is the registered trademark of Cambridge International Examinations. This document consists of 5 printed pages. © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education COMBINED SCIENCE 0653/31 Paper 3 Extended Theory October/November 2016 MARK SCHEME Maximum Mark: 80 Published 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 2016 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 2016 0653 31 © UCLES 2016 1 (a) (i) light / radiation (energy) ; kinetic (energy) ; [2] (ii) (average) speed = distance / time = 9 / 12 = 0.75 (m / s) ; [1] (b) (i) 0.9 (m / s) ; [1] (ii) straight line – constant acceleration ; curved line – not constant acceleration / deceleration ; [2] (c) (i) work done = mgh / = 10 × 10 × 6 ; = 600 (J) ; [2] (ii) power = energy transferred / time taken ; = 600 / 120 = 5 (W) [2] 2 (a) neutrons 12 ; electrons 11 ; [2] (b) 2,8,1 ; [1] (c) same (number) ; [1] (d) (i) loss of one electron ; [1] (ii) Neon / Ne ; [1] (e) Li (actual 180 °C) 100 – 200 °C ; Cs (actual 28.5 °C) 21 – 35 °C ; [2] (f) NaCl is a compound / strong forces between ions / particles ; NaCl solution is a mixture / weak forces between water and ions / NaCl ; [2]

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0653 31 © UCLES 2016 3 (a) geotropism / geotropic ; [1] (b) auxins ; (produced) at tip of seedling ; gather on side of seedling away from light ; cause more cell elongation on dark side ; [3] (c) (i) the number of germinating seeds increases as the pH increases ; the idea that low pH shows greater acidity ; use of data to support description; [2] (ii) acid denatures the enzymes (needed for germination) / owtte ; [1] (iii) (3 / 20 × 100 =) 15 (%) ; [1] (d) (i) reference to sulfur dioxide / nitrogen oxides ; one from description of process causing emission of polluting gases ; description of mixing / dissolving of gases in rainwater ; [max 2] (ii) acid rain reduces germination / growth / causes crop to die / avp ; [1] 4 (a) (i) evaporation / molecules break free (from surface) ; (thermal energy from Sun causes) water molecules to move faster / gain more K.E. ; (more) molecules moving fast enough / have enough energy to escape surface ; [3] (ii) paint trough white / polished metal trough / other reasonable suggestion ; [1] (b) (i) refraction ; [1] (ii) two diverging rays from same point on stick to the surface ; [max 3] at least one ray refracted (to eye) ; refracted rays diverge ; rays to eye projected back and converge to show the equivalent point on the image ;

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0653 31 © UCLES 2016 (c) sound (waves for speech and hearing) ; description of sound waves – need for a medium / description of compression and rarefaction / longitudinal / any other correct ; microwaves (between mobile phones) ; description of microwaves – e / m radiation / no need for medium / transverse / any other correct ; [max 3] 5 (a) (i) Fe2O3 + 3CO → 2Fe + 3 CO2 ; CO2 + C → 2CO ; C + O2 → CO2 ; [3] (ii) CO2 / carbon dioxide ; forms CO / carbon monoxide / loses oxygen ; or Fe2O3 / iron (III) oxide / iron oxide / Fe3+ / iron ions ; forms Fe / iron / loses oxygen / (ions) gain electrons ; [2] (b) (i) aluminium is more reactive than carbon ; [1] (ii) (ions) must be mobile / able to move ; [1] (iii) (Al 3+) gains (3 electrons) and (O2–) loses (2 electrons) ; [1] (c) (i) (aluminium) lighter / lightweight / less dense / resists corrosion better ; [1] (ii) (alloys) stronger (than pure Al) ; [1] 6 (a) (i) 48 °C ; [1] (ii) the activity decreases at higher temperatures ; [1] (b) (i) growth / repair ; [1] (ii) vitamins / named vitamin ; [2] prevent diseases / named disease / role of named vitamin ; (iii) (milk B) it contains less fat ; [1] (c) prevents constipation ; [1]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0653 31 © UCLES 2016 7 (a) (i) 1.5 + 0.5 + 0.6 = 2.6 (V) ; [1] (ii) R = V ÷ I / 0.5 ÷ 0.3 ; = 1.67 / 1.7 (ohms) ; [2] (iii) power = V × I ; = 2.6 × 0.3 = 0.78 / 0.8 (W) ; [2] (b) if in parallel, lamp would light even if motor not turning / owtte ; [1] 8 (a) (i) petroleum ; [1] (ii) boiling point ; [1] (b) (i) C3H6 ; [1] (ii) ethene ; [1] (iii) test bromine / bromine water ; C3H8 no change / stays orange and C2H4 (orange) to colourless ; [2] (c) (octane +) oxygen → carbon dioxide + water ; [1] 9 (a) umbilical cord ; an artery ; placenta ; oxygen ; [4] (b) (i) sexual intercourse ; sharing needles ; blood transfusions ; from mother to baby at birth ; from mother to baby during breast feeding ; avp ; [max 2] (ii) reduces immunity / makes a person more susceptible to disease ; attacks white (blood) cells ; [max 2]