Cambridge IGCSE Science - Combined 0653 — 2015 May/June Paper 2 · Variant 1

This document consists of 23 printed pages and 1 blank page. DC (NF/FD) 98898/4 © UCLES 2015 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 7 1 3 7 1 2 7 3 9 8 * COMBINED SCIENCE 0653/21 Paper 2 (Core) 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 0653/21/M/J/15 © UCLES 2015 1 (a) Fig. 1.1 shows an early type of airship filled with hydrogen gas. Fig. 1.1 A hydrogen molecule consists of two hydrogen atoms bonded together. Each hydrogen atom contains a small number of subatomic particles. (i) State the names and numbers of the subatomic particles in most hydrogen atoms. … … [2] (ii) State the type of bonding involved in a hydrogen molecule. … [1] (iii) The use of hydrogen for airships declined following a disaster in which an airship caught fire. Fig. 1.2 Write a word equation for the combustion of hydrogen. + [2] (iv) The combustion of hydrogen is an exothermic reaction. State the meaning of the term exothermic. … … [1]

3 0653/21/M/J/15 © UCLES 2015 [Turn over (v) Hydrogen can be displaced from an acid by reaction with another substance. Name a substance that could be used to displace hydrogen safely from an acid. Explain your answer in terms of the reactivity series. … … … [2] (b) Fig. 1.3 shows a modern weather balloon containing hydrogen or helium gas. ER[RIZHDWKHULQVWUXPHQWV EDOORRQ K\GURJHQRUKHOLXPJDV Fig. 1.3 Explain why helium is safer to use than hydrogen. … … … [1]

4 0653/21/M/J/15 © UCLES 2015 (c) Modern hot air balloons burn propane gas to heat air which inflates the balloon. SURSDQHWDQNV EXUQHUV Fig. 1.4 Propane is a hydrocarbon. Fig. 1.5 shows a model of a propane molecule. FDUERQDWRP K\GURJHQDWRP Fig. 1.5 State the molecular formula of propane. … [1]

5 0653/21/M/J/15 © UCLES 2015 [Turn over 2 (a) Most of the chemicals in living things are compounds made from two or more elements chemically joined together. Choose words from the list of elements below to complete the sentences. Each word may be used once, more than once or not at all. carbon hydrogen magnesium nitrogen oxygen potassium phosphorus sulfur (i) The elements contained in carbohydrates are … , … and … [1] (ii) The elements contained in fats are … , … and … [1] (b) Fig. 2.1 shows an animal cell. ; < Fig. 2.1 (i) Name the parts of the cell shown by labels X and Y on Fig. 2.1. X … Y … [2] (ii) One function of a cell is to carry out respiration which needs a constant supply of oxygen. Outline how oxygen gets from the alveoli of the lungs to a muscle cell. … … … [2]

6 0653/21/M/J/15 © UCLES 2015 (c) Energy is released by respiration in cells. Explain why the rate of respiration increases in some cells during exercise. … … [1] (d) Food stores in the body are broken down by respiration to release energy during exercise. Some people exercise when they are trying to lose weight. Table 2.1 shows the approximate energy needed for a person of body mass 70 kg to do 30 minutes of different types of exercise. Table 2.1 type of exercise energy needed for 30 minutes of exercise / kJ cycling 850 golf 670 jogging 1260 swimming 830 walking 580 Sarbjit and Anna each have a body mass of 70 kg. They both exercise for 90 minutes. During this time they do 30 minutes each of three different exercises. Calculate the total energy needed for each girl’s exercise, as follows. (i) Sarbjit did jogging, swimming and golf. total energy needed = … kJ Anna did cycling, walking and swimming. total energy needed = … kJ [1]

7 0653/21/M/J/15 © UCLES 2015 [Turn over (ii) State and explain which girl’s exercises were more effective for losing weight. … … … [2] (iii) Suggest one reason why the energy values given in Table 2.1 cannot be exactly the same for everyone doing the exercises. … … [1]

8 0653/21/M/J/15 © UCLES 2015 3 Fig. 3.1 shows a man on a snowboard moving down a hill. Fig. 3.1 Fig. 3.2 shows a graph of the man’s speed as he goes down the hill. 0 0 10 20 30 speed m / s time / s D 10 20 30 40 50 60 C B A Fig. 3.2 (a) State the force that causes the man to move downhill. … [1] (b) Describe the motion of the man between points A and B, … … B and C. … … [2]

9 0653/21/M/J/15 © UCLES 2015 [Turn over (c) Calculate the distance travelled by the man between points B and C. State the formula you use and show your working. formula working distance = … m [2] (d) The man on the snowboard wants to go faster down the hill. Explain in terms of the forces acting on the man and his snowboard why (i) he covers the underside of the snowboard with wax to make it smooth, … … [1] (ii) he bends down low on the snowboard while going down the hill. … … [1] (e) Snow is made of solid ice crystals. In the box below, draw a diagram to show the arrangement of particles in a solid. One particle has been drawn for you. You need to draw at least 11 more. [2]

10 0653/21/M/J/15 © UCLES 2015 4 (a) A sample of soil is taken from near a city where coal has been burned for many years. Full-range indicator (Universal Indicator) is added to some pure water. The soil sample is mixed with the water and filtered. The indicator shows that the pH of the water is 3. (i) Describe the change in colour of the indicator. from … to … [1] (ii) Burning coal produces an acidic gas called sulfur dioxide. Explain why the sample of soil has a low pH. … … … [2] (iii) In order to improve soil, by reducing its acidity, limestone is sometimes added. Limestone consists mainly of calcium carbonate. Complete the word equation for the reaction occurring between calcium carbonate and hydrochloric acid. calcium carbonate + hydrochloric acid carbon dioxide + + [2]

11 0653/21/M/J/15 © UCLES 2015 [Turn over (b) Some students are asked whether the size of the pieces of calcium carbonate used in a reaction with dilute hydrochloric acid affects the rate of reaction. Fig. 4.1 shows the apparatus they use to investigate the problem. gas jar water calcium carbonate dilute hydrochloric acid carbon dioxide Fig. 4.1 The reaction is repeated with differently-sized pieces of calcium carbonate and the time taken to fill the gas jar with carbon dioxide is measured for each repeat. (i) Describe how the size of the pieces of calcium carbonate used affects the time taken to fill the gas jar with carbon dioxide. … … … [1] (ii) Describe how changing one of the other reaction conditions will affect the rate of this reaction. … … … [1]

12 0653/21/M/J/15 © UCLES 2015 5 (a) Fig. 5.1 shows two flowers of the same species. IORZHU$ IORZHU% Fig. 5.1 (i) On Fig. 5.1 draw an arrow to show the transfer of pollen from flower A to flower B during pollination. [2] (ii) From Fig. 5.1 describe two adaptations of this flower for insect pollination. Use only features visible in Fig. 5.1. 1 … … 2 … … [2]

13 0653/21/M/J/15 © UCLES 2015 [Turn over (b) A student sets up an experiment to investigate the conditions needed for germination of seeds. She uses cotton wool and seeds as shown in Fig. 5.2. GLVK GDPSFRWWRQZRRO ƒ& LQOLJKW GDPSFRWWRQZRRO ƒ&LQIULGJH LQGDUN GDPSFRWWRQZRRO ƒ& LQGDUN GU\FRWWRQZRRO ƒ& LQOLJKW GLVK GLVK GLVK Fig. 5.2 After a few days the dishes are examined. Table 5.1 shows what the student observes. Table 5.1 dish number observations 1 all seeds germinated 2 no germination 3 no germination 4 all seeds germinated (i) Use the results in Table 5.1 to confirm that the following conditions are needed for germination. warmth … … water … … [2] (ii) Study the evidence in Table 5.1 to decide whether light is needed for germination. Explain your answer. … … [1] (iii) State one other condition, not investigated in the experiment, that is needed for germination of seeds. … [1]

14 0653/21/M/J/15 © UCLES 2015 6 Many different musical instruments are played in an orchestra. Table 6.1 shows the lowest and highest frequencies for the sounds produced by some musical instruments in an orchestra. Table 6.1 instrument lowest frequency / Hz highest frequency / Hz bassoon 58 932 cello 65 659 clarinet 147 1865 flute 262 2093 harp 31 3322 trumpet 165 1000 violin 196 2637 (a) State which instrument in the table (i) has the smallest range of frequencies, … [1] (ii) produces a sound with the shortest wavelength, … [1] (iii) produces a sound with the lowest pitch. … [1]

15 0653/21/M/J/15 © UCLES 2015 [Turn over (b) String instruments, such as the violin and guitar, produce sound waves when the strings are plucked. (i) On Fig. 6.1 draw a diagram to show the motion of a violin or guitar string when it is plucked. Fig. 6.1 [1] (ii) State how your diagram would change if the string produces a louder sound. … [1] (c) A listener at an outdoor pop concert is 66 m away from the stage. Calculate the delay between the time a guitar string is plucked and the time she hears the sound. The speed of sound in air is 330 m / s. Show your working. time delay = … s [2]

16 0653/21/M/J/15 © UCLES 2015 7 (a) Complete Table 7.1 to show the physical states of the halogens at room temperature. Table 7.1 halogen physical state chlorine bromine iodine [2] (b) Fig. 7.1 shows the apparatus used for the electrolysis of molten lead bromide. SRZHU VXSSO\ FDUERQURGV PROWHQOHDGEURPLGH +($7     ² Fig. 7.1 (i) Complete the labelling of the diagram, choosing from the words below. ammeter anode cathode electrolyte insulator resistor water [2] (ii) Place an X on the diagram to show where bromine would appear. [1]

17 0653/21/M/J/15 © UCLES 2015 [Turn over (iii) Describe the appearance of the bromine. … … [1] (c) Bromine is produced on a large scale by passing chlorine gas through sodium bromide solution. Fig. 7.2 shows how this can be demonstrated in the laboratory. start chlorine sodium bromide solution after a few minutes Fig. 7.2 (i) Name the substance, other than bromine, that is formed in the beaker. … [1] (ii) Suggest a suitable compound from which iodine could be extracted using a similar method to that shown in Fig. 7.2. … [1] (iii) Use your knowledge of Group VII of the Periodic Table to explain your answer to (ii). … … [1]

18 0653/21/M/J/15 © UCLES 2015 8 Fig. 8.1 shows a food chain in Africa. JUDVV ]HEUD OLRQ Fig. 8.1 (a) (i) The source of energy for the food chain is sunlight. The grass needs sunlight for photosynthesis. Complete the word equation for photosynthesis. carbon dioxide + … … + oxygen [2] (ii) From the food chain in Fig. 8.1 name one consumer, … one carnivore. … [2] (b) In most habitats the organisms have more than one food source. These can be added to the food chain to make a food web. Use the statements below to add labels and arrows to the food chain in Fig. 8.1 to build up a food web. A lion also eats a hyena. A hyena eats a zebra. You may use the word ‘hyena’ rather than trying to draw one. [2]

19 0653/21/M/J/15 © UCLES 2015 [Turn over (c) The element carbon is transferred along the food chain in Fig. 8.1. (i) Describe how carbon atoms are transferred from the zebra to the lion. … … [1] (ii) Not all the carbon in the zebra is transferred to the lion. State two reasons why some of the carbon atoms in the zebra are not transferred to the lion. 1 … … 2 … … [2]

20 0653/21/M/J/15 © UCLES 2015 9 Fig. 9.1 shows a caravan which uses an electric heater to supply warm air to heat the caravan and to heat water. FDUDYDQ PDLQVHOHFWULFLW\ VXSSO\FDEOH Fig. 9.1 Fig. 9.2 shows a circuit diagram for the electric heater. It contains two elements, one for heating the air and one for heating the water. mains electricity supply element heating air element heating water hot water tank Fig. 9.2 (a) (i) The air around the electric heater is heated. The heated air then flows around the caravan and warms the people sitting inside. State the method of thermal energy transfer involved in the flow of air around the caravan. … [1] (ii) Thermal energy from the element heating water must be transferred through the wall of the element into the water around it. State the method of thermal energy transfer through the wall of the element. … [1]

21 0653/21/M/J/15 © UCLES 2015 [Turn over (iii) The hot water must be kept hot in the hot water tank after the heater is switched off. Suggest and explain a method of keeping the water hot for a long time in the tank after heating. method … … explanation … … [2] (b) The circuit diagram in Fig. 9.2 only allows both heating elements to be switched on together, or both heating elements to be switched off together. Complete the circuit diagram in Fig. 9.3 to show a circuit which allows the people in the caravan to have one element switched on and the other element switched off. Fig. 9.3 [2]

22 0653/21/M/J/15 © UCLES 2015 (c) When both elements are switched on, the current in the water-heating element is 8 A and the current in the air-heating element is 4 A. Suggest how the resistance of the water-heating element compares with the resistance of the air-heating element. Explain your answer. comparison of resistances … … explanation … … [3] (d) One day the caravan owner touches the metal casing of the heater. He is surprised to suffer an electrical shock. Suggest an electrical hazard that might be responsible for this happening. … … [1]

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24 0653/21/M/J/15 © UCLES 2015 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.). 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. CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International General Certificate of Secondary Education MARK SCHEME for the May/June 2015 series 0653 COMBINED SCIENCE 0653/21 Paper 2 (Core 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 21 © Cambridge International Examinations 2015 1 (a) (i) 1 proton ; 1 electron ; [2] (ii) covalent; [1] (iii) hydrogen + oxygen ; water ; [2] (iv) heat energy given out / increase in temperature ; [1] (v) named metal above hydrogen in reactivity series up to and including calcium ; [2] above hydrogen in reactivity series ; (b) noble gas so unreactive (with oxygen) / not flammable ; [1] (c) C3H8 ; [1] [Total: 10] 2 (a) (i) carbon, hydrogen, oxygen ; [1] (ii) carbon, hydrogen, oxygen ; [1] (b) (i) X cell membrane ; [2] Y cytoplasm ; (ii) from alveoli into blood / capillaries ; [max 2] in blood ; in red cells ; carried by haemoglobin ; any valid reference to diffusion ; (c) (energy needed) for contraction of muscles / movement ; [1] (d) (i) 2760 and 2260 ; [1] (ii) Sarbjit because she used more energy ; [2] she broke down a greater amount of food stores ; (allow ecf if calculation in (i) indicates the wrong girl) (iii) activities done at different rates owtte ; [1] [Total: 11]

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0653 21 © Cambridge International Examinations 2015 3 (a) weight (accept gravity) ; [1] (b) A to B: accelerating/going faster ; [2] B to C: constant speed ; (c) (distance =) speed x time (in any form) ; [2] (OR use of area under graph between B and C) = 25 x 30 = 750 (m) ; (d) (i) reduces friction(al force) (opposing effect of gravity) ; [1] (ii) reduces air resistance (opposing effect of gravity) ; [1] (e) [2] or acceptable equivalent with at least 12 spheres in total regular pattern ; most touching ; [Total: 9] 4 (a) (i) green to yellow / orange / red ; [1] (ii) gas dissolves in / reacts with water etc. in atmosphere ; [2] acid rain falls on soil ; (iii) calcium chloride ; [2] water ; (b) (i) decreasing size of pieces decreases time taken / [1] increases rate / v.v. ; (ii) increasing concentration (of acid) decreases time / [1] increases rate / v.v. OR increasing temperature decreases time / increases rate / v.v. ; [Total: 7]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0653 21 © Cambridge International Examinations 2015 5 (a) (i) arrow correctly drawn from anther of flower A ; [2] to stigma of flower B ; (allow 1 mark if the arrow points to the correct structures but is the wrong way round) (ii) large petals ; [max 2] anthers inside flower ; stigma inside flower ; (b) (i) no germination at 4°C / in dish 3 ; [2] no germination when water is absent / in dish 2 ; (ii) (light is not needed) no mark [1] because germination took place in dish 4 ; (iii) oxygen ; [1] [Total: 8] 6 (a) (i) cello ; [1] (ii) harp ; [1] (iii) harp ; [1] (b) (i) or similar diagram to illustrate a vibrating string ; [1] (ii) greater amplitude / owtte ; [1] (c) (time delay =) distance / speed of sound ; = 66 / 330 = 0.2 (s) ; [2] [Total: 7]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0653 21 © Cambridge International Examinations 2015 7 (a) liquid solid 1 for 2 correct, 2 for 3 correct ;; [2] (b) (i) anode cathode ; electrolyte ; [2] (ii) X on or near left-hand electrode under or just above electrolyte surface ; [1] (iii) brown / orange / yellow, colouration of, electrolyte / gas ; [1] (c) (i) (sodium) chloride ; [1] (ii) (sodium) iodide ; [1] (iii) trend in reactivity with other halides: Cl > Br >I / chlorine [1] is more reactive than iodine ; [Total: 9] 8 (a) (i) water ; [2] sugar / glucose ; (ii) zebra / lion ; [2] lion ; (b) correct arrow drawn from zebra to hyena ; [2] correct arrow drawn from hyena to lion ; (c) (i) by eating ; [1] (ii) carbon lost in waste materials / urine / faeces ; [max 2] carbon lost during respiration as carbon dioxide ; not all the zebra eaten ; not all the zebra digested / absorbed ; [Total: 9]

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