Cambridge IGCSE Science - Combined 0653 — 2015 May/June Paper 3 · Variant 2

This document consists of 22 printed pages and 2 blank pages. DC (LK/CGW) 98907/3 © UCLES 2015 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 5 3 7 9 3 6 3 7 0 6 * COMBINED SCIENCE 0653/32 Paper 3 (Extended) May/June 2015 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 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 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 0653/32/M/J/15 © UCLES 2015 1 (a) Table 1.1 gives some facts about the element astatine and its position in the Periodic Table. Table 1.1 element period Group proton number astatine 6 VII 85 From the information in Table 1.1, deduce the number of electrons in the outer shell of an astatine atom. number … explanation … …[2] (b) Fig. 1.1 shows a demonstration of the reaction between hydrogen and the oxygen in air. gas jar drops of a colourless liquid cover mixture of hydrogen and air Fig. 1.1 A burning splint is placed over a gas jar containing a mixture of hydrogen and air. The cover is removed. The mixture explodes.

3 0653/32/M/J/15 © UCLES 2015 [Turn over (i) Drops of a colourless liquid are observed inside the gas jar. Describe a chemical test and the result that shows that the liquid is water. test … … result …[2] (ii) Write a symbolic chemical equation for the reaction between hydrogen and oxygen, including state symbols. …[3] (iii) Fig. 1.2 shows the arrangement of electrons in the outer shells of a hydrogen atom and an oxygen atom. H O Fig. 1.2 Draw a diagram to show the arrangement of outer electrons in a water molecule. [2]

4 0653/32/M/J/15 © UCLES 2015 2 (a) The element nitrogen is needed by all living things to make protein. Nitrogen is absorbed by plant roots in the form of nitrate ions that are dissolved in the water in the soil. Fig. 2.1 shows a root hair cell. Fig 2.1 Describe how the shape of the root hair cell is important for its function. … … …[2] (b) In some areas of the world the soil does not have enough nitrogen. Fig. 2.2 shows a Venus flytrap. This plant can grow in areas of low nitrogen by capturing insects and digesting the protein in their bodies to obtain the nitrogen it needs. insect leaf Fig 2.2 The leaves produce an enzyme which breaks down the protein in the insect’s body by chemical digestion. Describe what is meant by chemical digestion. … … …[2]

5 0653/32/M/J/15 © UCLES 2015 [Turn over (c) Some students are studying how temperature affects an enzyme similar to the one produced by the Venus flytrap. They add a solution of the enzyme to cubes of protein and incubate the cubes at a range of temperatures. The time taken to digest each cube is shown in Table 2.1. Table 2.1 temperature / ° C time taken / minutes 10 5.8 20 3.6 30 2.1 40 1.7 50 1.9 60 3.5 (i) State which temperature shows the fastest digestion. …[1] (ii) In terms of particles, describe and explain fully what happens to the speed of digestion when the temperature is increased from 10° C to 30° C, … … … when the temperature is increased above 50° C. … … …[4]

6 0653/32/M/J/15 © UCLES 2015 3 The pole vault is an athletics event in which the athlete attempts to get over a very high bar with the help of a long pole. Fig. 3.1 shows an athlete at five stages during a pole vault. stage 1 stage 2 stage 3 stage 4 stage 5 landing mat Fig. 3.1 The athlete runs with his pole, places the pole in the ground and pushes himself upwards. He rises to the height of the bar, remains there for a brief moment, then falls over the bar to the landing mat. Fig. 3.2 shows a simplified graph of the athlete’s speed during the pole vault. 1 1 0 2 3 time/s 4 0 2 3 4 speed m / s 5 A B C Fig. 3.2

7 0653/32/M/J/15 © UCLES 2015 [Turn over (a) The letters A, B and C on the graph in Fig. 3.2 correspond to three of the five stages in the pole vault shown in Fig. 3.1. (i) Explain why A on the graph corresponds to stage 1. … …[1] (ii) Explain why B on the graph corresponds to stage 4. … …[1] (b) The energy of the athlete changes during this pole vault. He starts with chemical energy in his muscles. State the main energy changes that follow before he lands on the mat. from chemical energy to kinetic energy to … energy to … energy [2] (c) Describe the motion of the athlete between points B and C. …[1] (d) Using the graph in Fig. 3.2, calculate the distance travelled by the athlete between 2 seconds and 3 seconds. Show your working. distance = … m [2] (e) The athlete uses a long metal vaulting pole. On a hot day, the length of the metal pole is a few millimetres longer than its length on a cold day. Explain why this happens in terms of the particle structure of the metal. … … …[2]

8 0653/32/M/J/15 © UCLES 2015 4 (a) Fig. 4.1 shows a sample of rock containing bands of iron oxide. quartz (silicon dioxide) iron oxide Fig. 4.1 Some information about the formation of this rock is shown below: • this rock was formed about 2.5 billion years ago; • oxygen was produced by bacteria in the oceans; • iron compounds were dissolved in the oceans; • iron compounds were oxidised by reacting with oxygen to make insoluble iron oxide; • iron oxide settled on the ocean bed to produce the dark layers in the rock. (i) State one physical change and one chemical change that occurred when the rock shown in Fig. 4.1 was formed. physical change … … chemical change … …[2] (ii) Describe the difference between a physical change and a chemical change. … …[1]

9 0653/32/M/J/15 © UCLES 2015 [Turn over (b) For a long time, very little of the oxygen produced by bacteria in part (a) was released into the atmosphere. Fig. 4.2 shows the approximate composition of the Earth’s atmosphere 3 billion years ago. nitrogen carbon dioxide Fig. 4.2 Apart from the difference in oxygen content, describe one main difference and one main similarity between the composition of the atmosphere 3 billion years ago and our present day atmosphere. difference … similarity …[2] (c) Iron can be extracted from iron oxide in a blast furnace. (i) State the name of a gaseous substance which reduces the iron oxide to iron in the furnace. …[1] (ii) State the raw material(s) that are used by the furnace to supply this gaseous substance. …[1]

10 0653/32/M/J/15 © UCLES 2015 (iii) The temperature in a blast furnace can reach 1300° C. Copper can be extracted from copper oxide in the laboratory at a lower temperature. Explain why less energy is needed to extract copper from copper oxide than is needed to extract iron from iron oxide. … … …[2] (iv) The molten iron extracted from iron oxide contains silicon dioxide as an impurity. Explain how silicon dioxide is removed from the molten iron in the blast furnace. … … …[2]

11 0653/32/M/J/15 © UCLES 2015 [Turn over 5 (a) Fig. 5.1 shows the external view of the heart, including the blood vessels that take blood into and out of the heart. The coronary arteries are also shown. left ventricle coronary arteries aorta Fig. 5.1 (i) On Fig. 5.1 use label lines to label a pulmonary artery, the vena cava. [2] (ii) Some people suffer from coronary heart disease. Explain what is meant by coronary heart disease. … … …[2]

12 0653/32/M/J/15 © UCLES 2015 (b) Table 5.1 shows the average number of cigarettes smoked per adult each day in four countries. The number of deaths due to coronary heart disease per 100 000 of the population per year is also shown. Table 5.1 country average number of cigarettes smoked per adult each day number of deaths per year / 100 000 population A 7.4 185 B 4.1 76 C 3.3 35 D 5.5 152 (i) Use the data in Table 5.1 to describe the relationship between smoking cigarettes and coronary heart disease. … … …[2] (ii) Country E, not included in the table, had different results. The adults in country E smoked on average 4.6 cigarettes per day. The number of deaths from coronary heart disease per 100 000 of the population / year was 23. Suggest two possible reasons why the results for country E do not follow the relationship you identified in part (i). 1 … … 2 … … [2]

13 0653/32/M/J/15 © UCLES 2015 [Turn over (c) Cigarette smoking can cause infections of the lungs. Fig. 5.2 shows two types of cell in the lining of the airway leading to the lungs. mucus cilia Fig. 5.2 Smoking damages the cilia and also encourages more mucus to be produced. Explain how both of these effects can increase the chances of infection in the lungs. cilia damage… … … extra mucus production … … …[2]

14 0653/32/M/J/15 © UCLES 2015 6 Fig. 6.1 shows apparatus called a ripple tank. This is used by students for experiments to investigate water waves. The electric motor causes the board to vibrate. At a constant speed of rotation, the motor produces waves at a constant rate. power supply water waves water waves vibrating board shallow tank of water electric motor Fig. 6.1 Fig. 6.2 shows a close-up side view of some water waves during an experiment in the tank. direction of travel of waves P Fig. 6.2 (a) (i) Explain why water waves are examples of transverse waves. … …[1] (ii) Give an example of a longitudinal wave. …[1] (b) Fig. 6.2 shows a change in the wavelength of the waves as they reach point P. The amplitude of the wave does not change. Name one other property of the wave motion that remains the same after passing point P. …[1]

15 0653/32/M/J/15 © UCLES 2015 [Turn over (c) As the speed of the motor is increased, the board vibrates more rapidly. When the board is vibrating at 10 vibrations per second, the students cannot hear any sound. When the board is vibrating at 30 vibrations per second, the students can hear a sound with a low pitch. (i) Explain why the students cannot hear any sound when the board makes 10 vibrations per second. … …[1] (ii) When the board vibrates at 30 vibrations per second, the wavelength of the water waves before they reach point P, is 1.0 cm. Calculate the speed of the waves before they reach point P. State the formula you use, show your working and give the unit of your answer. formula working speed of waves = … unit … [3] (iii) Describe how the sound is transmitted from the vibrating board through the air to the students standing at some distance from the ripple tank. … … …[2]

16 0653/32/M/J/15 © UCLES 2015 7 (a) Petroleum (crude oil) is a mixture of hydrocarbons. Fig. 7.1 summarises the process which separates the mixture into some of its useful fractions. petroleum fractional distillation gasoline refinery gas diesel oil Fig. 7.1 Each of these fractions consists of a mixture of hydrocarbons including alkanes. Fig. 7.2 shows a model of a molecule of one of the alkanes in refinery gas. hydrogen atom carbon atom Fig. 7.2 (i) Write the name and molecular formula of this alkane. … …[2]

17 0653/32/M/J/15 © UCLES 2015 [Turn over (ii) The petroleum fractions have different boiling point ranges. This allows them to be separated by fractional distillation. Describe how boiling point is affected by the size of the molecules and explain your answer. relationship between boiling point and size of molecules … … explanation … … …[3] (b) Fig. 7.3 shows the electrolysis of copper chloride solution. anode cathode copper chloride solution carbon electrodes power supply + – Fig. 7.3 Bubbles of chlorine gas appear at the anode. By referring to the movement of ions and electrons, explain the formation of this gas. … … … …[2]

18 0653/32/M/J/15 © UCLES 2015 8 (a) Humans clear forests in some parts of the world so that the land can be used to grow crops. Fig. 8.1 shows the burning of trees to clear forests. 3. wind carries smoke to neighbouring trees 1. trees being felled 2. combustion of wood Fig. 8.1 When the trees burn, smoke is produced that contains carbon particles. The wind carries the smoke to neighbouring trees. This causes the rate of photosynthesis in these trees to be reduced. Explain how the following cause the rate of photosynthesis to be reduced. (i) Particles of carbon landing on the upper surfaces of the leaves. … …[1] (ii) Particles of carbon blocking the stomata in the leaves. … …[1] (b) A few days after the fire finishes, the concentration of oxygen in the atmosphere near the felled trees is measured and compared with the concentration before the fire. It has decreased. (i) Explain what causes the concentration of oxygen in the atmosphere to decrease in the days after the fire. … … …[2]

19 0653/32/M/J/15 © UCLES 2015 [Turn over (ii) Describe one effect that this decrease in oxygen concentration could have on the remaining living organisms in the area. … …[1] (c) Deforestation causes the carbon dioxide concentration of the Earth’s atmosphere to increase. Describe one consequence of an increase in the carbon dioxide concentration of the Earth’s atmosphere. … …[1] (d) Humans also cause the concentration of carbon dioxide in the atmosphere to increase by burning fossil fuels. Name one other substance produced by the burning of fossil fuels. …[1]

20 0653/32/M/J/15 © UCLES 2015 9 A student is building a model car. Fig. 9.1 shows a circuit he designs for the electrical equipment he wants in the car. sidelamps headlamps heater 12 V Fig. 9.1 (a) Fig 9.2 shows the lamps and heater he uses for his model. The markings on the lamps and heater are shown below the pictures. sidelamp headlamp heater 6 V, 0.5 A 6 V, 2 A 12 V, 120 W Fig. 9.2 State and explain what is meant by each of these quantities when written on a component. 6 V … … 120 W … …[4]

21 0653/32/M/J/15 © UCLES 2015 (b) When the student switches on the circuit in Fig. 9.1, the lamps glow only very faintly. He has not designed his circuit correctly. On Fig. 9.3 complete the circuit diagram to show the sidelamps and heater connected so that all the lamps glow brightly. headlamps, each 6 V, 2 A 12 V Fig. 9.3 [2] (c) Calculate the current through the heater when it is working properly at 12 V and 120 W. State the formula that you use and show your working. formula working current = … A [2] (d) The heater is designed to transfer thermal energy to the air to warm the inside of the model car. Name the method of thermal energy transfer involved when the warm air circulates inside the car. …[1]

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24 0653/32/M/J/15 © UCLES 2015 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 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.).

® IGCSE is the registered trademark of Cambridge International Examinations. CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International General Certificate of Secondary Education MARK SCHEME for the May/June 2015 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 May/June 2015 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 – May/June 2015 0653 32 © Cambridge International Examinations 2015 1 (a) 7 ; number of outer electrons = Group number ; [2] (b) (i) cobalt chloride test paper / anhydrous cobalt chloride ; turns (from blue to) pink ; OR anhydrous copper sulphate ; turns (from white to) blue ; [2] (ii) 2H2(g) + O2(g)
2H2O(l) formulae ; balancing ; states ; [3] (iii) 2 shared pairs ; 4 non-bonding electrons on O ; [2] (max 1 if any other error) 2 (a) large surface area ; for rapid / efficient diffusion / uptake / absorption of water / ions / minerals / nutrients ; [2] (allow a relevant named ion) (b) breaking down large / insoluble molecules ; into small / soluble molecules ; that can be absorbed ; [max 2] (c) (i) 40 °C ; [1] (ii) from 10 °C to 30 °C speed (of digestion) was increasing ; due to more frequent collisions (between molecules) ; molecules have more kinetic energy ; above 50 °C speed (of digestion) was decreasing ; due to denaturation of the enzyme ; shape of enzyme / active site is changing ; [max 4] (two marks to be awarded for each temperature)

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0653 32 © Cambridge International Examinations 2015 3 (a) (i) running at constant speed ; [1] (ii) reference to low (forward) speed / speed decreasing ; [1] (b) kinetic (energy)
gravitational (potential) / potential (energy) ; potential (energy)
kinetic (energy) ; [2] (c) (falls to zero then) accelerating / going faster ; [1] (d) (distance =) ½ base × height / ½ × 1 × 4 ; [2] = 2 (m) (e) rise in temperature means particles vibrate more energetically / owtte ; which increases (average) distance between particles / owtte ; [2] 4 (a) (i) physical: (iron oxide) settles / produced layers in rock / iron compounds dissolved ; chemical: compounds oxidised to iron oxide / oxygen produced by bacteria ; [2] (ii) chemical change produces a new substance / ora ; [1] (allow other correct differences) (b) (assume reference to ancient atmosphere if not specified) difference: more carbon dioxide in ancient atmosphere ; (allow other reasonable ideas based on the diagram e.g. noble gases, polluting gases or water vapour) similarity: nitrogen largest component ; [2] (c) (i) carbon monoxide ; [1] (ii) coke / coal and air / oxygen ; [1] (iii) copper forms weaker bonds with oxygen than does iron ; copper is lower than iron in the reactivity series ; [2] (iv) (limestone / calcium carbonate decomposes to produce) calcium oxide ; which reacts with silicon dioxide ; to form molten slag / calcium silicate ; which floats on / forms a separate layer on molten iron ; [max 2]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0653 32 © Cambridge International Examinations 2015 5 (a) (i) pulmonary artery correctly labelled ; vena cava correctly labelled ; [2] (ii) blockage / narrowing of coronary arteries ; (due to) cholesterol / fat deposits / plaques ; lack of oxygen supplied to heart muscle ; [max 2] (b) (i) number of deaths (per 100 000 population per year) increased as the (average) number of cigarettes smoked increased ; appropriate reference to figures ; [2] (ii) less stress ; less fat in the diet ; more exercise taken ; inherited likelihood (of developing CHD) ; more people die from other causes ; improved / more effective treatment for CHD available ; [max 2] (c) cilia cannot (beat to) remove the mucus bacteria / pathogens ; and then 1 from bacteria / pathogens are trapped / contained in mucus OR bacteria / pathogens stay in the lungs / breed in the mucus ; [max 2] 6 (a) (i) water goes up and down at right angles to direction of travel of wave / owtte [1] (ii) oscillating spring / sound waves / avp ; [1] (b) speed ; [1] (c) (i) frequency less than lower limit of hearing ; [1] (ii) (v =) fλ ; = 30 × 1 = 30 ; unit: cm / s ; [3] (unit must be consistent with working) (iii) by vibrations (of air) ; from particle to particle / through particles / by collision between particles ; (in the form of) compressions and rarefactions / as longitudinal waves ; [max 2]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0653 32 © Cambridge International Examinations 2015 7 (a) (i) ethane ; C2H6 ; [2] (ii) fraction with higher boiling point (range) contains larger molecules ; larger molecules have greater intermolecular forces ; more energy required to overcome larger intermolecular forces ; [3] (b) chloride / Cl – ions move to anode / positive electrode ; opposite charges attract ; electrons pass from chloride / Cl – ions to anode / positive electrode / correct electrode equation ; [max 2] (allow chloride ions are oxidised) 8 (a) (i) particles reduce amount of light (landing on the leaf) ; [1] (ii) carbon dioxide prevented from entering leaf ; [1] (b) (i) less photosynthesis to produce oxygen ; reference to respiration by animals or decomposers using up oxygen ; the combustion of wood ; [max 2] (ii) less oxygen available for respiration ; [1] (c) global warming / increased greenhouse effect / consequence of global warming described e.g. rising sea level / climate change / examples of extreme weather events ; [1] (d) water (vapour) / sulfur dioxide / nitrogen oxide(s) / carbon monoxide / soot ; [1]

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0653 32 © Cambridge International Examinations 2015 9 (a) two points from potential difference / volts / voltage ; required to drive the current ; 6 (volts) required to allow lamp to work properly / safely ; two points from power / watts / wattage ; energy / second transferred ; 120 (watts) is the safe maximum / owtte ; [max 4] (b) sidelamps remain in series with each other and each pair in parallel with the battery ; heater, sidelamps, headlamps all in parallel ; [2] (c) (I =) P / V or equivalent ; (I =) 120 / 12 = 10 (A) ; [2] (d) convection ; [1]