Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2016 May/June Paper 2 · Variant 3

This document consists of 30 printed pages and 2 blank pages. DC (LK/JG) 110185/4 © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 9 0 0 0 6 5 3 5 9 7 * CO-ORDINATED SCIENCES 0654/23 Paper 2 (Core) May/June 2016 2 hours 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 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 32. 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 0654/23/M/J/16 © UCLES 2016 1 Aluminium foil is made when aluminium is rolled into thin sheets. Aluminium foil is used to make food containers and fizzy-drink cans. roll of aluminium foil food container fizzy-drink can (a) (i) State the property of aluminium that allows it to be rolled into thin sheets. …[1] (ii) Many types of food and drink are acidic. State the property of aluminium that makes it suitable for making food containers and fizzy-drink cans. …[1] (b) Aluminium used to make fizzy-drink cans contains small amounts of other metals. As well as the liquid, the fizzy-drink can contains gas under pressure. (i) State the word used for a mixture of metals. …[1] (ii) Suggest a reason why aluminium, containing small amounts of other metals, rather than pure aluminium, is used for fizzy-drink cans. … … …[2]

3 0654/23/M/J/16 © UCLES 2016 [Turn over (c) Fig. 1.1 shows the process that is used to extract aluminium from aluminium oxide. – + electrolyte containing molten aluminium oxide gas bubbles d.c. power supply aluminium Fig. 1.1 (i) Name the process shown in Fig. 1.1. … [1] (ii) Label the cathode on Fig. 1.1. [1] (iii) State the element that is contained in the gas bubbles shown in Fig. 1.1. …[1] (d) Aluminium oxide contains aluminium ions and oxide ions. (i) State, in terms of electrons, how a metal atom is converted into an ion. … …[1] (ii) In aluminium oxide, two aluminium ions are present for every three oxide ions. State the chemical formula of aluminium oxide. …[1]

4 0654/23/M/J/16 © UCLES 2016 2 Fig. 2.1 shows some blood, as seen through a microscope. X Y Fig. 2.1 (a) (i) Name the parts of the blood labelled X and Y. X … Y … [2] (ii) State the function of the part labelled X. … …[1] (iii) Name two other components of the blood not shown in Fig. 2.1. 1 … 2 … [2]

5 0654/23/M/J/16 © UCLES 2016 [Turn over (b) Fig. 2.2 shows a possible route that the blood might take, in travelling from the vena cava to one of the kidneys. Complete the route by filling in the blanks in the boxes to show the name of a blood vessel or a chamber of the heart. vena cava right … right ventricle pulmonary … lung … vein left atrium left … aorta … artery kidney Fig. 2.2 [5]

6 0654/23/M/J/16 © UCLES 2016 3 (a) Some oil leaks from an oil tanker. It forms a very thin layer of oil on the surface of the seawater. The density of the oil is 880 kg / m3. The density of seawater is 1025 kg / m3. Why does the oil float on top of the seawater? … …[1] (b) Fig. 3.1 represents a water wave on the surface of the sea. –0.50 –0.25 0.25 0.50 0 displacement / m 1 2 3 4 5 6 7 8 distance / m Fig. 3.1 (i) Determine the amplitude of the wave. … m [1] (ii) Determine the wavelength of the wave. … m [1] (iii) Two waves pass a fixed point in the sea over a period of 20 seconds. Calculate the frequency of the waves. frequency = … Hz [1]

7 0654/23/M/J/16 © UCLES 2016 [Turn over (c) The oil tanker is carrying crude oil. Crude oil is a non-renewable energy resource. Other energy resources are shown in Table 3.1. Table 3.1 non-renewable renewable coal geothermal energy hydroelectricity natural gas solar energy from ocean waves tidal energy (i) Identify two non-renewable energy resources by placing a tick (✓) in the non-renewable column. [1] (ii) Identify two renewable energy resources by placing a tick (✓) in the renewable column. [1] (d) The depth of the sea below the oil tanker is determined by sending out pulses of ultrasound waves through the water. The ultrasound pulses reflect off the sea bed and the echoes are detected on the oil tanker. Humans cannot hear ultrasound waves. (i) State the maximum audible frequency for a human. … Hz [1] (ii) State the minimum audible frequency for a human. … Hz [1]

8 0654/23/M/J/16 © UCLES 2016 (iii) The echo of an ultrasound wave emitted by the oil tanker is detected 1.2 seconds later. The speed of ultrasound waves in water is 1500 m / s. Calculate the depth of the sea below the oil tanker. State the formula you use and show your working. formula working distance = … m [2]

9 0654/23/M/J/16 © UCLES 2016 [Turn over 4 In the African savannah (grassland), zebras feed on grass. They are preyed on by carnivores, such as lions. The lions have fleas in their fur. The fleas feed on the lions’ blood. (a) Construct a food chain containing four organisms, based on this description. [2] (b) In the savannah, state the term that describes (i) grasses and other plants, …[1] (ii) zebras and lions, …[1] (iii) zebras, but not lions. …[1] (c) In ecosystems such as the savannah, carbon atoms circulate in the carbon cycle. Name a carbon compound that is (i) absorbed by grasses, …[1] (ii) transferred from zebras to lions, …[1] (iii) released by lions into the atmosphere. …[1]

10 0654/23/M/J/16 © UCLES 2016 5 (a) Fig. 5.1 shows two headlamps in a car. The headlamps are connected in parallel with the battery. A switch and a fuse are also connected in the circuit. battery switch fuse lamps Fig. 5.1 Draw the circuit diagram for the car headlamps, shown in Fig. 5.1, using circuit symbols. [2]

11 0654/23/M/J/16 © UCLES 2016 [Turn over (b) When the headlamps are switched on, visible light is emitted. Fig. 5.2 shows part of the electromagnetic spectrum. Visible light is part of the electromagnetic spectrum. On Fig. 5.2, write visible light in the correct place. [1] gamma radiation ultraviolet infra-red radio waves Fig. 5.2 (c) A small panel of the bodywork of the car is painted using an electrostatic paint spray gun. The paint droplets leave the spray gun with a positive electric charge. The bodywork panel is given a negative electric charge. This is shown in Fig. 5.3. paint positively charged paint droplets negatively charged bodywork panel + – Fig. 5.3 Explain why this method ensures that the paint reaches the panel. … …[1]

12 0654/23/M/J/16 © UCLES 2016 (d) Fig. 5.4 shows the car travelling across a bridge made from concrete sections. There are gaps between each section, which are filled with a flexible material, such as rubber. rubber concrete road concrete road Fig. 5.4 Why are the gaps filled with a flexible material? … … …[2] (e) The driver of the car sees a bus in his mirror, as shown on Fig. 5.5. BUS Fig. 5.5 Apart from any changes in size, describe two characteristics of the image that the driver sees. 1 … 2 … [2]

13 0654/23/M/J/16 © UCLES 2016 [Turn over 6 (a) The inheritance of sex in humans depends on the sex chromosomes. State the sex chromosomes present in (i) a body cell of a female, …[1] (ii) an egg cell, …[1] (iii) a body cell of a male, …[1] (iv) a sperm cell. …[1] (b) State the name for a fertilised egg cell. …[1] (c) Fig. 6.1 shows the female reproductive system and associated structures, shown in cross section. R S Fig. 6.1 (i) On Fig. 6.1, label with the letter P, the place where fertilisation occurs. On Fig. 6.1, label with the letter Q, the place where the ball of cells resulting from a fertilised egg cell becomes implanted for further development. [2] (ii) Name the structures labelled R and S. R … S … [2] (iii) State one function of the part labelled S. … …[1]

14 0654/23/M/J/16 © UCLES 2016 7 (a) Manganese dioxide, a black powder, is added to an aqueous solution of a compound, J. This causes compound J to decompose and release a gas that relights a glowing splint. Name this gas. …[1] (b) Fig. 7.1 shows apparatus and materials a student uses to investigate the speed of the reaction described in (a). gas bubbles gas syringe solution of compound J 2.0 g of black manganese dioxide piston Fig. 7.1 The student measures the time, in seconds, taken to collect 100 cm3 of gas. She then finds the speed of reaction using the equation shown. speed of reaction = 100 time in seconds cm3 / s (i) Calculate the speed of reaction if the time taken to produce 100 cm3 of gas is 40 seconds. speed of reaction = … cm3 / s [1] (ii) Suggest one change the student can make to her experiment that decreases the time taken to collect 100 cm3 of gas. … …[1]

15 0654/23/M/J/16 © UCLES 2016 [Turn over (iii) Manganese dioxide is a catalyst for the decomposition of compound J. The student uses 2.0 g of manganese dioxide in her experiment. State the mass of manganese dioxide that remains at the end of the reaction. Explain your answer. mass of manganese dioxide remaining … g explanation … … … [2] (iv) Suggest two facts about manganese dioxide that would show that manganese is a typical transition metal. 1 … … 2 … … [2]

16 0654/23/M/J/16 © UCLES 2016 8 Fig. 8.1 shows the inside of a refrigerator. freezing compartment Fig. 8.1 (a) (i) The air inside the refrigerator is cooled. On Fig. 8.1, draw one straight arrow to show the movement of the air cooled by the freezing compartment. [1] (ii) State the name of this heat transfer process. …[1] (b) In the freezing compartment of the refrigerator, there is an ice tray with a volume of 300 cm3. The tray is completely filled with ice. The density of ice is 0.92 g / cm3. Calculate the mass of the ice in the tray. State the formula you use and show your working. formula working mass = …g [2]

17 0654/23/M/J/16 © UCLES 2016 [Turn over (c) The ice has been made by freezing some water. Fig. 8.2 shows the arrangement of the particles in a liquid and in a solid. A B Fig. 8.2 Use the letters A or B from Fig. 8.2 to fill in the blank and complete the statement to explain your choice. Diagram … shows a solid because the particles … … …[2] (d) There is a lamp inside the refrigerator. The supply voltage is 220 V and the current through the lamp is 0.04 A. (i) Show that the resistance of the lamp is 5500 Ω. State the formula you use and show your working. formula working [2] (ii) Two lamps identical to the lamp in (d) (i) are connected in parallel. The combined resistance of the two lamps is one of the following values. 2750 Ω 5500 Ω 11 000 Ω 22 000 Ω Circle the correct value for the combined resistance. Explain your answer. … …[1]

18 0654/23/M/J/16 © UCLES 2016 (e) Food kept in a refrigerator stays fresh for longer. Another way to keep food fresh is to treat it with ionising radiation. (i) Describe what is meant by the term ionising radiation. … …[1] (ii) Name one type of ionising radiation. …[1] (iii) State one danger of ionising radiation to the human body. …[1]

19 0654/23/M/J/16 © UCLES 2016 [Turn over 9 Table 9.1 shows information of some of the elements found in the same period of the Periodic Table. Table 9.1 Group IV V VI VII VIII element symbol Si P S Cl Ar proton number 14 15 16 17 18 melting point / °C 1687 44 115 –102 –189 (a) (i) State which period of the Periodic Table contains the elements shown in Table 9.1. …[1] (ii) Name the most reactive metal that is in the same period as the elements in Table 9.1. …[1] (iii) Explain the meaning of the following statement. Silicon has a proton number of 14. … …[1] (iv) State the number of electrons in a phosphorus atom. number of electrons … [1] (v) Explain why a phosphorus atom is electrically neutral (neither positive nor negative). … … …[2] (vi) Describe the general trend in the melting points of the elements in Table 9.1. … …[1]

20 0654/23/M/J/16 © UCLES 2016 (b) Argon is in Group VIII of the Periodic Table. (i) State the name of the family of elements in Group VIII. …[1] (ii) Fig. 9.1 shows caesium stored in a sealed glass container. Caesium is a reactive metal. argon caesium Fig. 9.1 Argon is also present in the container. Why is argon used to fill the rest of the container rather than air? … … …[2] (c) Chlorine is in Group VII of the Periodic Table. (i) State why a colourless solution of sodium iodide becomes dark brown when it reacts with chlorine. … …[1] (ii) Explain why chlorine is used to treat water that is supplied for drinking. … … …[2]

21 0654/23/M/J/16 © UCLES 2016 [Turn over 10 A student pinned a young bean plant to a cork board. The plant was on its side with light shining on it from above, as shown in Fig. 10.1. cork board pin stand bean plant light Fig. 10.1 Fig. 10.2 shows the appearance of the plant after two days. cork board stand light Fig. 10.2 (a) State two characteristics of living organisms that cause the change in the appearance of the bean plant. 1 … 2 … [2]

22 0654/23/M/J/16 © UCLES 2016 (b) The student concluded that his experiment showed that the plant stem responds to light by growing towards it. (i) State the name for the type of response where a plant grows towards the light. …[1] (ii) The student’s experiment does not justify his conclusion. Explain why not. … … …[2] (iii) Explain why growing towards the light increases the survival chances of a plant. … …[1]

23 0654/23/M/J/16 © UCLES 2016 [Turn over 11 (a) An athlete is training for a race. She runs along a race track. She accelerates from rest at a constant rate for 20 seconds and reaches a maximum speed of 6 m / s. She continues at this speed for another 20 seconds. During the next 5 seconds she slows down steadily and stops. (i) On the grid below draw a speed / time graph to show the motion of the athlete. 0 0 2 1 4 3 6 5 8 7 10 20 30 40 50 time / s speed m / s [3] (ii) Complete the sentence below, choosing the correct forms of energy. As the athlete runs, the … energy in the food she has eaten changes to … energy and thermal energy. [2]

24 0654/23/M/J/16 © UCLES 2016 (b) Fig. 11.1 shows another athlete running a race. Fig. 11.1 Two forces acting on the athlete are his weight E and air resistance F, which slows the athlete. Draw arrows on Fig. 11.1 to show the directions of these two forces. Label each force clearly using the letters E and F. [2]

25 0654/23/M/J/16 © UCLES 2016 [Turn over (c) A spectator is watching the race. He is standing behind other spectators and cannot see the race directly. He uses a periscope to see the race more clearly. Fig. 11.2 shows the path of a ray of light passing through the periscope. normal normal mirror H mirror G Fig. 11.2 (i) On Fig. 11.2, use the letter i to indicate the angle of incidence of the ray striking mirror G. [1] (ii) The angle of incidence of the ray striking mirror G is 45°. State the angle of reflection. Explain your answer. angle of reflection = … ° explanation … …[2]

26 0654/23/M/J/16 © UCLES 2016 12 (a) Petroleum is a fossil fuel. (i) Name one other fossil fuel. …[1] (ii) In the right hand column of Table 12.1 write a tick (✓) if the sentence about petroleum is correct or a cross (✗) if it is incorrect. Table 12.1 It is a single compound made of hydrogen and carbon. It is extracted from the Earth’s crust. It can be used as a fuel for cars. It has taken millions of years to form. [2] (b) Fig. 12.1 shows two processes which are carried out at an oil refinery. hot petroleum alkanes process Z mixture of alkanes and alkenes fractional distillation hot catalyst Fig. 12.1

27 0654/23/M/J/16 © UCLES 2016 [Turn over (i) Explain why fractional distillation is used to process petroleum. … … …[2] (ii) State whether the changes that take place during fractional distillation are physical changes or chemical changes. Explain your answer. type of change … explanation … … …[2] (c) Process Z, shown in Fig. 12.1, is used to produce alkenes from alkanes. (i) Name process Z. …[1] (ii) State which one of the four molecules, L, M, N and O, in Fig. 12.2 is an alkene. Give a reason for your answer. H H H H C C O H H H H C H H H H H C C H H H H H C C H H molecule L molecule M molecule N molecule O Fig. 12.2 molecule … reason … …[2]

28 0654/23/M/J/16 © UCLES 2016 13 Scientists have investigated the possibility of humans living on the planet Mars. To live on Mars people would need to grow plants on the planet. (a) Explain why humans would be dependent on these plants. … …[1] (b) Table 13.1 shows some of the conditions on Mars, compared to Earth. Table 13.1 Earth Mars distance from the Sun / millions of km 149.6 227.9 mean surface temperature / °C 14 –55 carbon dioxide in the atmosphere / % 0.03 95 availability of water large amounts traces (i) Explain why the distance of the planet from the Sun would be important for plants growing on Mars. … …[1] (ii) State one way in which water is needed to keep plants alive. …[1] (iii) State whether the carbon dioxide concentration of the atmosphere on Mars (compared to that on Earth) will increase plant growth. Explain your answer. … … …[1]

29 0654/23/M/J/16 © UCLES 2016 (iv) If large numbers of plants were grown on Mars for a long period of time, predict how this might change the planet’s atmosphere. Explain your answer. change … explanation … … [2]

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32 0654/23/M/J/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 7 printed pages. © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education CO-ORDINATED SCIENCES 0654/23 Paper 2 Core Theory May/June 2016 MARK SCHEME Maximum Mark: 120 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 0654 23 © Cambridge International Examinations 2016 1 (a) (i) malleability ; [1] (ii) unreactive (with acids) ; [1] (b) (i) alloy ; [1] (ii) alloy is stronger ; so can withstand the increased pressure inside the can ; [2] (c) (i) electrolysis ; [1] (ii) label line goes to any point on the back line showing the cathode ; [1] (iii) oxygen ; [1] (d) (i) reference to electron loss ; [1] (ii) Al2O3 ; [1] [Total: 10] 2 (a) (i) X = red blood cell ; Y = plasma ; [2] (ii) carries oxygen ; [1] (iii) (named type of) white blood cells ; platelets ; [2] (b) atrium ; artery ; pulmonary ; ventricle ; renal ; [5] [Total: 10] 3 (a) oil is less dense than sea water ; [1] (b) (i) 0.50 (m) ; [1] (ii) 4 (m) ; [1] (iii) 0.1 (Hz) ; [1] (c) (i) coal and natural gas in non-renewable column ; [1]

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 23 © Cambridge International Examinations 2016 (ii) geothermal, hydroelectricity, solar, waves, tidal any two in renewable column ; [1] (d) (i) 20 000 (Hz) (allow 25 000 Hz) ; [1] (ii) 20 (Hz) (allow 10 Hz) ; [1] (iii) (distance =) speed × time or 1500 × 1.2 ; = 1800 m and then divide by 2 = 900 (m) ; [2] [Total: 10] 4 (a) grass → zebra → lion → flea four organisms in correct order ; correct arrows ; [2] (b) (i) producers ; [1] (ii) consumers ; [1] (iii) herbivores / primary consumers ; [1] (c) (i) carbon dioxide ; [1] (ii) carbohydrate / sugar / protein / any correct organic compound ; [1] (iii) carbon dioxide ; [1] [Total: 8] 5 (a) lamps in parallel / all symbols correct ; all else correct ;; [2] (b) visible placed between UV and IR ; [1] (c) all droplets have opposite charge to panel and so are attracted ; [1] (d) concrete road expands when hot ; rubber can be squashed to allow for expansion ; to prevent road from breaking when hot ; [max 2] (e) laterally inverted ; upright ; virtual ; [max 2] [Total: 8]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 23 © Cambridge International Examinations 2016 6 (a) (i) XX ; [1] (ii) X ; [1] (iii) XY ; [1] (iv) X / Y ; [1] (b) zygote ; [1] (c) (i) P on the oviduct ; Q on the uterus ; [2] (ii) R = oviduct ; S = ovary ; [2] (iii) produces / releases egg cells / hormones ; [1] [Total: 10] 7 (a) oxygen ; [1] (b) (i) 2.5 ; [1] (ii) increase temperature / increase concentration of J / increase the surface area of manganese dioxide ; [1] (iii) 2.0 (g) ; catalysts are not consumed / permanently changed ; [2] (iv) forms a coloured compound ; reference to use as catalyst ; [2] [Total: 7] 8 (a) (i) single arrow going down ; [1] (ii) convection ; [1] (b) (mass =) density × volume or 0.92 × 300 ; = 276 (g) ; [2] (c) A and all particles touching ; regularly arrangement ; [2] (d) (i) (R =) V / I ; 220 / 0.04 (= 5500 Ω) ; [2]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 23 © Cambridge International Examinations 2016 (ii) 2750 (Ω) no mark combined resistance of resistors in parallel is less than the value of either resistor ; [1] (e) (i) radiation that ionises atoms / removes electrons from atoms ; [1] (ii) alpha / beta / gamma / X rays ; [1] (iii) cancer, cell mutation etc. ; [1] [Total: 12] 9 (a) (i) third / 3 ; [1] (ii) sodium ; [1] (iii) a silicon atom / nucleus contains 14 protons ; [1] (iv) 15 ; [1] (v) equal numbers of protons as electrons / protons and electrons balance / cancel each other ; protons are positive and electrons are negative ; [2] (vi) generally decrease (left to right) across the period ; [1] (b) (i) noble / inert gases ; [1] (ii) argon highly unreactive / does not react with caesium ; oxygen / water (from air) react easily with caesium ; [2] (c) (i) iodine is produced ; [1] (ii) chlorine sterilises / kills harmful microorganisms ; reference to removing risk of disease ; [2] [Total: 13] 10 (a) growth / movement ; sensitivity ; [2] (b) (i) phototropism ; [1] (ii) stem would grow upwards anyway, with or without light / no control experiment ; growing against / responding to, gravity ; [2] (iii) helps get light for photosynthesis ; [1] [Total: 6]

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 23 © Cambridge International Examinations 2016 11 (a) (i) section from 0–20 s ; section from 20–40 s ; section from 40–45 s ; [3] (ii) chemical ; kinetic ; [2] (b) arrow labelled E going downwards ; arrow labelled F going to the left ; [2] (c) (i) angle of incidence correctly labelled ; [1] (ii) 45° ; angle of incidence = angle of reflection ; [2] [Total: 10] 12 (a) (i) natural gas / coal / peat ; [1] (ii) X
X
(4 correct = 2, 2 or 3 correct = 1) [2] (b) (i) to separate the compounds in petroleum / to produce simpler mixtures ; (unrefined) petroleum is not useful / fractions are useful / owtte ; [2] (ii) (physical) the idea that only changes of state are involved ; new substances are not produced ; [2] (c) (i) (catalytic / thermal) cracking ; [1] (ii) (O) it is a hydrocarbon ; it is unsaturated / contains a double bond / fits CnH2n ; [2] [Total: 10] 13 (a) for food / oxygen ; [1]

Page 7 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 23 © Cambridge International Examinations 2016 (b) (i) if closer then warmer / more light ; (ORA) [1] (ii) needed for photosynthesis / for turgor / as solvent ; [1] (iii) (yes – no mark) because needed for photosynthesis ; [1] (iv) more oxygen / less CO2 ; due to photosynthesis ; [2] [Total: 6]