Cambridge IGCSE Science - Combined 0653 — 2016 May/June Paper 3 · Variant 2

This document consists of 22 printed pages and 2 blank pages. DC (NF/SG) 116211/3 © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 0 4 0 6 1 2 6 1 2 6 * COMBINED SCIENCE 0653/32 Paper 3 (Extended) May/June 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 0653/32/M/J/16 © UCLES 2016 1 Fig. 1.1 shows some parts of the human alimentary canal and its associated organs. mouth salivary gland tongue liver stomach pancreas small intestine colon rectum Fig. 1.1 (a) Use the labels in Fig. 1.1 to complete Table 1.1. Table 1.1 function name of organ(s) ingestion … absorption of digested food … secrete digestive enzymes stomach and … and … [4]

3 0653/32/M/J/16 © UCLES 2016 [Turn over (b) The nutrients that have been absorbed from the digestive system travel in the blood to the body cells. Fig. 1.2 shows a longitudinal section of a capillary next to some body cells. wall of capillary body cell Fig. 1.2 The arrows show the direction of movement of glucose from the blood to the cells of the body. Describe how the structure of the capillary allows this movement to take place effectively. … … … … [2]

4 0653/32/M/J/16 © UCLES 2016 (c) Fig. 1.3 shows the effect of pH on the activity of an enzyme which is secreted into the food in the stomach. The environment in the stomach has a low pH because of the presence of hydrochloric acid. 1 2 3 4 5 6 7 8 9 10 pH of reaction enzyme activity Fig. 1.3 (i) State the optimum pH for this enzyme. … [1] (ii) The stomach contents enter the duodenum. The pH there is approximately 8. Explain in detail why the enzyme shows no activity when it enters the duodenum. … … … … [2] (iii) There are enzymes in the duodenum which digest the food after it has left the stomach. On Fig. 1.3 draw a curve to suggest how the activity of an enzyme secreted into the duodenum varies with pH. [2]

5 0653/32/M/J/16 © UCLES 2016 [Turn over Please turn over for Question 2

6 0653/32/M/J/16 © UCLES 2016 2 (a) Lead bromide, PbBr2, can be broken down into its elements using the apparatus shown in Fig. 2.1. – + d.c. power supply electrode A molten lead bromide Fig. 2.1 (i) Name the process shown in Fig. 2.1. … [1] (ii) Give the symbols of the ions present in molten lead bromide. … [1] (iii) Name the element produced at electrode A and state the colour of this element. name … colour … [2] (b) In a similar process, aqueous copper chloride solution is broken down into a metal and chlorine gas. (i) Write the symbol equation for the reaction, including state symbols. … [2] (ii) Describe the chemical test for chlorine gas. test … result … … [2]

7 0653/32/M/J/16 © UCLES 2016 [Turn over (c ) (i) Describe the trend in the boiling points of the elements going down Group VII of the Periodic Table, from chlorine to iodine. … [1] (ii) Fluorine is another element in Group VII. Use the Periodic Table to determine the electronic structure of an atom of fluorine. … [1] (iii) An atom of fluorine has a nucleon number of 19. Calculate the number of neutrons in this atom. number of neutrons = … [1]

8 0653/32/M/J/16 © UCLES 2016 3 Fig. 3.1 shows a gravity racer. A gravity racer is a small cart with four wheels and no engine. It is steered by a driver as it runs down a sloping track. Fig. 3.1 (a) The mass of the cart and driver is 100 kg. State the name given to the force on this mass due to the effect of gravity. … [1] (b) Fig. 3.2 shows the track becoming horizontal at the bottom of the slope. Fig. 3.2 The cart accelerates down the slope and then moves along the horizontal track for a distance before the driver applies the brakes and the cart stops. Fig. 3.3 shows a speed / time graph for the motion of the cart.

9 0653/32/M/J/16 © UCLES 2016 [Turn over speed m / s time / s 10 8 6 4 2 0 0 2 4 6 8 10 Fig. 3.3 (i) On Fig. 3.3 write the letter P at the point when the brakes are first applied. [1] (ii) Use Fig. 3.3 to calculate the distance travelled by the cart 1. while it moves at constant speed. State any formula you use and show your working. formula working distance = … m 2. from the time the brakes are applied until it comes to a stop. Show your working. distance = … m [3]

10 0653/32/M/J/16 © UCLES 2016 (c) Another cart with driver has a mass of 150 kg. This cart travels down the slope through a vertical height of 10 m before entering the horizontal section of the track. (i) Complete the energy transfers that take place while the cart is moving. potential energy From … at the top of the slope kinetic to … energy on the track to … energy as the cart stops. [1] (ii) Calculate the potential energy lost. (gravitational field strength, g = 10 N / kg). State the formula you use and show your working. formula working potential energy = … J [2] (iii) Calculate the maximum possible speed of the cart at the bottom of the slope. State the formula you use and show your working. formula working speed = … m / s [3]

11 0653/32/M/J/16 © UCLES 2016 [Turn over 4 Fig. 4.1 shows a germinating seed and a diagram of one of the root hair cells as seen through the microscope. root hair area root hair cell Fig. 4.1 (a) Use the following terms to complete the sentences. You may use each term once, more than once, or not at all. amino acids cell membrane cell wall ions nucleus phloem xylem The root hair cell has a … to control what enters and leaves the cell. It has a large surface area to absorb water and … . Water goes from the cell to the … to be taken to the rest of the plant. [3] (b) A few days later the seedling in Fig. 4.1 develops leaves above ground and starts to photosynthesise. (i) Write the symbol equation for photosynthesis. … light chlorophyll … [2] (ii) Describe the role of chlorophyll in photosynthesis. … … … … [2]

12 0653/32/M/J/16 © UCLES 2016 5 Fig. 5.1 shows the fractional distillation of petroleum. Four of the fractions are labelled P, Q, R and S. hot petroleum P Q R S Fig. 5.1 (a) State which fraction from Fig. 5.1 has the lowest boiling point range, … the greatest molecular size. … [2] (b) Alkanes and alkenes are two types of hydrocarbon. (i) Name the process used in the manufacture of alkenes from alkanes. … [1]

13 0653/32/M/J/16 © UCLES 2016 [Turn over (ii) Fig. 5.2 shows three molecules. C H H H H H C O H C H H H H H C H C H H H H C A B C Fig. 5.2 State which molecule is an alkene and give a reason for your answer. molecule … reason … … [1] (iii) Alkanes and alkenes can be distinguished by a chemical test. Name the chemical used in this test and state the observations for propane and for propene. chemical name … propane observation … … propene observation … … [3]

14 0653/32/M/J/16 © UCLES 2016 6 Global warming causes ice caps to melt. This causes a rise in sea level. (a) Warming of the water in the oceans causes the sea level to rise for a different reason. Explain this reason. … … [1] (b) Global warming happens when more of the infra-red radiation coming from the Sun is trapped in the Earth’s surface and atmosphere. (i) Table 6.1 shows part of the electromagnetic spectrum. Table 6.1 gamma rays X-rays radio waves In Table 6.1, place infra-red radiation in the correct position in the electromagnetic spectrum. [1] (ii) A student said he thought infra-red radiation travels from the Sun more slowly than sunlight. Explain why the student is not correct. … … [1] (c) Global warming causes more water to evaporate from the sea, as the average speed of the molecules in the sea increases. This causes the temperature of the water in the sea surface to decrease slightly. Suggest why evaporation causes a decrease in temperature in terms of the movement of water molecules. … … … … [2] (d) When the Sun is shining on the Earth’s surface, the temperature of the land increases more quickly than the temperature of the sea. Suggest one reason why this happens. … … [1]

15 0653/32/M/J/16 © UCLES 2016 [Turn over 7 Fig. 7.1 shows the energy flow in an ecosystem on an island. The unit for each flow is kJ / m2 / year. respiration decomposers light energy landing on plants 2 400 000 glucose in plants 114 200 primary consumers (herbivores) secondary consumers (carnivores) 3450 39 200 11 500 2830 620 8050 52 000 E Fig. 7.1 (a) (i) Calculate the efficiency with which light energy landing on the plants is converted to glucose. Show your working. efficiency = …% [2] (ii) Calculate E, the amount of energy passed on to the primary consumers. Show your working E = … kJ / m2 / year [1] (iii) Explain why there are not many trophic levels in this ecosystem. … … … [1] (iv) Describe one way in which the plants use the energy released by respiration. … [1]

16 0653/32/M/J/16 © UCLES 2016 (b) Acid rain can affect ecosystems. The island is affected by acid rain that is carried by the wind from a factory on a different island. (i) Describe how the factory could cause this acid rain. … … … … [2] (ii) The acid rain reduces the growth of the plants on the island. Suggest and explain how this affects the number of carnivores in the ecosystem in Fig. 7.1. … … … … [2]

17 0653/32/M/J/16 © UCLES 2016 [Turn over 8 Fig. 8.1 shows a piece of calcium reacting with dilute hydrochloric acid. calcium thermometer acid Fig. 8.1 (a) Complete the sentences about this reaction. In this reaction the temperature increases. This shows that this is an … reaction. The temperature rises because … energy is converted into … energy. [3] (b) Describe and explain, in terms of colliding particles, any effect on the speed of the reaction caused by reducing the temperature of the acid. effect … explanation … … [2] (c) (i) Describe and explain any effect on the speed of the reaction in Fig. 8.1 caused by replacing the piece of calcium by a piece of copper. effect … explanation … … [2] (ii) Describe the method of extraction of copper from copper oxide. … … [1]

18 0653/32/M/J/16 © UCLES 2016 9 A student wants to investigate the current through an electric buzzer. He designs the circuit in Fig. 9.1 to use in his investigation. V buzzer Fig. 9.1 (a) (i) Name the component represented by this symbol. … [1] (ii) State and explain why the student includes this component in his circuit. … … … … [2]

19 0653/32/M/J/16 © UCLES 2016 [Turn over (iii) The student has left out an important component from his circuit that is needed to measure the current. On Fig. 9.2 complete the circuit diagram and include the symbol for this missing component in its correct place. V Fig. 9.2 [2]

20 0653/32/M/J/16 © UCLES 2016 (b) The student uses the correct circuit for his experiment. Fig. 9.3 shows his results plotted as a graph. 0 2 4 6 8 10 12 0.060 0.050 0.040 0.030 0.020 0.010 0 current / A potential difference / V Fig. 9.3 The resistance of the buzzer is given by the formula resistance = potential difference (p.d.) current The student says that the resistance of the buzzer is lower when the p.d. is 12 V than when the p.d. is 6 V. The resistance at 12 V is 200 Ω. Use information from the graph in Fig. 9.3 to calculate the resistance at 6 V to show that he was correct. resistance at 6 V = … Ω [2]

21 0653/32/M/J/16 © UCLES 2016 (c) The buzzer emits a very loud sound at 3000 Hz with a wavelength of 0.11 m. A student 1 km away from the buzzer hears the sound after a short time. Calculate the time taken by the sound to reach the student. State any formula you use and show your working. formula working time = … s [3]

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24 0653/32/M/J/16 © UCLES 2016 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 – 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.

® 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 0653/32 Paper 3 Extended Theory May/June 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 May/June 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 – May/June 2016 0653 32 © Cambridge International Examinations 2016 1 (a) ingestion mouth ; absorption of digested food small intestine ; secrete digestive enzymes two from salivary glands ; small intestine ; pancreas ; [4] (b) has a thin wall / (wall) one cell thick / walls are permeable ; (reject semi-permeable) allows (rapid) diffusion ; [2] (c) (i) 2.7 ±0.1 ; [1] (ii) enzyme has become denatured ; use of graph e.g. enzyme shows no activity at pH 8 / above about 4.5 ; enzyme / active site has changed shape / enzyme cannot bind to substrate / owtte ; [max 2] (iii) smooth curve showing a rounded maximum ; maximum at pH 8 ±0.2 ; [2] 2 (a) (i) electrolysis ; [1] (ii) Pb2+ and Br – ; [1] (iii) name: bromine ; colour: brown / orange-brown ; [2] (b) (i) CuCl2(aq) → Cu(s) + Cl2 (g) state symbols (aq) on LHS and (s) and (g) on RHS ; all formulae correct ; [2] (ii) test: (damp) litmus paper ; result: bleaches / turns white ; [2] (c) (i) increase ; [1] (ii) 2, 7 ; [1] (iii) 10 ; [1]

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0653 32 © Cambridge International Examinations 2016 3 (a) weight ; (do not allow gravity or gravitational force) accept weight in a list if other members are neutral [1] (b) (i) P placed at co-ordinates (8, 8) ; [1] (ii) statement of formula distance = (average) speed × time / (distance =) area under graph ; working and answer 1. 8 × 4 = 32 (m) ; 2. 1 2 × 8 × 1 = 4 (m) ; [3] (c) (i) thermal / heat ; accept sound [1] (ii) working (PE =) m g h / 150 × 10 × 10 ; (= 150 × 10 × 10) = 15 000 (J) ; [2] (iii) use of PE lost = KE gained (= 15 000 J) ; use of (KE =) 1 2 m v2 / √(15 000 × 2 / 150) ; (√(15 000 × 2 / 150)) = 14.1 (m / s) (accept 14) ; [3] 4 (a) cell membrane ; ions ; xylem ; [3] (b) (i) 6CO2 + 6H2O → C6H12O6 + 6O2 correct formulae ; balanced (dependent on formulae) ; [2] (ii) traps light (energy) ; converts it to chemical energy ; [2] 5 (a) P ; S ; [2] (b) (i) (thermal / catalytic) cracking ; [1] (ii) molecule B contains a (C=C) double bond ; [1] (iii) (aqueous) bromine ; result for propane no change / mixture remains coloured ; result for propene decolourises ; [3]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0653 32 © Cambridge International Examinations 2016 6 (a) (thermal) expansion (of sea water) / (sea) water volume increases ; [1] (b) (i) infra-red located in correct position ; [1] (ii) all e / m radiation travels at same speed / speed of light ; [1] (c) faster / more energetic molecules (able to) escape / leave surface / evaporate ; (average) speed / energy of remaining molecules less / lower ; [2] (d) land surface better absorber of infrared radiation / other correct ; [1] 7 (a) (i) (114 200 ÷ 2 400 000) × 100 ; = 4.8 / 4.76(%) ; [2] (ii) (114 200 – 52 000 – 39 200) = 23 000 (kJ / m2 / year) ; [1] (iii) too much energy lost between trophic levels / not enough energy or very low energy (in secondary consumers / carnivores) to pass on to another level ; [1] (iv) protein synthesis / cell division / growth ; [1] (b) (i) burning fossil fuel ; (release of) sulfur dioxide / oxides of nitrogen (to the atmosphere) ; SO2 / NOx dissolves / mixes in / reacts with water / rain (water) ; [max 2] (ii) numbers would reduce (no mark) less energy / food available in plants for herbivores ; fewer herbivores to provide energy / feed the carnivores ; [max 2] 8 (a) exothermic ; chemical (potential) ; heat / thermal ; [3] (b) decreases ; particles collide less often / collide with less energy ; [2] (c) (i) speed of reaction is zero ; copper is less reactive than hydrogen / copper does not react with (dilute) acid ; [2] (ii) carbon reduction / heat with carbon ; [1] 9 (a) (i) variable resistor / variable resistance / rheostat ; [1] (ii) to change the resistance in the (main) circuit ; to change the current through the buzzer / p.d. across the buzzer ; [2]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0653 32 © Cambridge International Examinations 2016 (iii) ammeter symbol correctly drawn ; ammeter in series with buzzer and rest of circuit correct ; [2] (b) (correct reading from graph at 6 V is ) 0.015 A ; (resistance at 6 V = 6 ÷ 0.015) = 400 (Ω) ; [2] (c) v = f λ / 3000 × 0.11; = 330 (m / s) ; time = 1000 / 330 = 3.03 (s) ; (accept 3 s) (allow ecf from previous stage ) [3]