Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2015 May/June Paper 2 · Variant 3

This document consists of 28 printed pages. DC (RW/FD) 97579/4 © UCLES 2015 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 3 6 6 5 3 5 2 1 5 6 * CO-ORDINATED SCIENCES 0654/23 Paper 2 (Core) May/June 2015 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, 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 28. 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/15 © UCLES 2015 1 Table 1.1 shows some information about three elements A, B and C. Table 1.1 element group in Periodic Table group name reactive or unreactive electrical conductor or insulator A 1 alkali metals reactive B 7 halogens C 0 insulator (a) Add the five missing pieces of information to complete Table 1.1. [3] (b) Describe how the structure of the nucleus is used to place the elements in the order found in the Periodic Table. …[1] (c) Table 1.2 shows information about two different atoms, X and Y, of the element boron. Table 1.2 atom proton number nucleon number X 5 10 Y 5 11 (i) State and explain which of the atoms, X or Y, contains the same number of neutrons as protons. atom … explanation … …[1] (ii) State the word used to describe forms of an element that have atoms with different nucleon numbers. …[1]

3 0654/23/M/J/15 © UCLES 2015 [Turn over (d) Fig. 1.1 shows sodium reacting in water that contains a solution of full range indicator (Universal Indicator). sodium gas given off aqueous solution of full range indicator Fig. 1.1 (i) Name the gas that is given off in the reaction. …[1] (ii) State and explain how the pH of the solution changes during the reaction. … … …[2] (iii) State and explain one observation that would be different if the reaction is repeated using lithium instead of sodium. … … …[2]

4 0654/23/M/J/15 © UCLES 2015 2 (a) (i) A torch (flashlight) contains three cells, a lamp and a switch connected in series. Using the correct circuit symbols, draw the electrical circuit for the torch. [2] (ii) The voltage across the lamp is 4.5 V. The resistance of the lamp is 5 Ω. Calculate the current through the lamp. State the formula that you use, show your working and state the unit of your answer. formula working current = … unit …[3] (iii) The lamp from the torch has a resistance of 5 Ω when lit. Two identical lamps are connected together in a series circuit. State the combined resistance of the two lamps when lit and connected in series. … Ω [1]

5 0654/23/M/J/15 © UCLES 2015 [Turn over (b) Fig. 2.1 shows a ray of light from the torch that is reflected by a plane mirror. $ ' plane mirror torch % & Fig. 2.1 (i) Name angle B. … [1] (ii) Name angle C. … [1] (iii) State what happens to the value of angle C when the value of angle B is doubled. …[1]

6 0654/23/M/J/15 © UCLES 2015 3 Fig. 3.1 shows, for one country, the number of people recorded as newly infected with HIV each year from 1985 to 2010. 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 0 2000 year 4000 6000 8000 number of new HIV infections Fig. 3.1 (a) (i) State in which year the number of new HIV infections was greatest. …[1] (ii) Suggest one reason why the actual number of new HIV infections may have been greater than this. … …[1] (b) State two ways in which HIV can be transmitted within a population. 1 … 2 …[2] (c) (i) Use Fig. 3.1 to describe how the number of new HIV infections changed between 2006 and 2010. … … …[2] (ii) Suggest two possible reasons for this change. 1 … 2 …[2]

7 0654/23/M/J/15 © UCLES 2015 [Turn over 4 (a) A student rubs a balloon on his sweater. Charged particles move from the sweater to the balloon which becomes negatively charged. (i) Name the charged particles. … [1] (ii) The student charges a second balloon in the same way. Fig. 4.1 shows the two charged balloons next to each other. Fig. 4.1 State what happens to the balloons when the student brings the balloons very close together. Explain your answer. … … …[2]

8 0654/23/M/J/15 © UCLES 2015 (b) The student then bursts one of the balloons 83 m from a brick wall. This is shown in Fig. 4.2. student balloon brick wall 83 metres Fig. 4.2 The noise the balloon makes when it bursts travels through the air as a sound wave. The student hears an echo. (i) Explain why the student hears an echo. … …[1] (ii) Between the balloon bursting and the student hearing the echo, there is a delay. How far has the sound wave travelled in this time? …m [1] (iii) The time delay for the echo is 0.5 s. Use your answer to (ii) to calculate the speed of sound in air. State the formula that you use and show your working. formula working speed of sound = …m / s [2] (c) The student places the second balloon in a refrigerator. Explain in terms of particles why the balloon shrinks when placed in the refrigerator. … … … …[2]

9 0654/23/M/J/15 © UCLES 2015 [Turn over (d) Fig. 4.3 shows a large hot air balloon moving upwards. upward force = 8200 N weight = 7850 N Fig. 4.3 (i) Explain why the balloon rises. … …[1] (ii) The mass of the air in the hot air balloon is 2660 kg. The volume of the air in the hot air balloon is 2800 m3. Calculate the density of the air in the hot balloon in kg / m3. State the formula that you use and show your working. formula working density = …kg / m3 [2]

10 0654/23/M/J/15 © UCLES 2015 5 In some countries, sodium chloride is obtained from sea water or salt water lakes. (a) Describe how sodium chloride crystals can be obtained from sea water. … … …[2] (b) Sodium chloride is formed when sodium metal reacts in a container of chlorine gas. In this reaction, sodium atoms and chlorine atoms are changed into sodium ions and chloride ions. (i) Complete the explanations below in terms of protons and electrons. A sodium atom has no overall electrical charge because … … … A sodium ion has a positive electrical charge because … … … [3] (ii) Explain why strong bonds form between sodium ions and chloride ions. … …[1]

11 0654/23/M/J/15 © UCLES 2015 [Turn over (c) Fig. 5.1 shows laboratory apparatus that can be used to obtain chlorine from sodium chloride solution. d.c. power supply cathode anode sodium chloride solution chlorine gas 5 Fig. 5.1 (i) Name the process shown in Fig. 5.1. …[1] (ii) State the difference between the cathode and the anode. … …[1] Gas R in Fig. 5.1 is tested as shown below. pop burning splint (iii) Name gas R. …[1]

12 0654/23/M/J/15 © UCLES 2015 6 Fig. 6.1 shows part of a leaf in section, as it appears under a microscope. 3 4 5 6 ; 7 Fig. 6.1 (a) Plants lose water from their leaves in the form of water vapour. (i) State the name for the loss of water from leaves. …[1] (ii) Water inside the leaf evaporates and the water vapour then diffuses through pores in the leaf. On Fig. 6.1, use a label line with the letter E to show a place inside the leaf where water evaporates. [1] (iii) Name the pore in the leaf labelled X. …[1] (iv) State two environmental conditions that would increase the rate of this water loss. 1 … 2 …[2]

13 0654/23/M/J/15 © UCLES 2015 [Turn over (b) The main function of the leaf is photosynthesis. (i) With reference to Fig. 6.1, identify the type of cells in which most photosynthesis occurs, and explain your answer. cells … explanation … …[2] (ii) Explain why the pore at X is important for photosynthesis. … …[1]

14 0654/23/M/J/15 © UCLES 2015 7 Oxygen combines with many elements to form oxides. (a) Fig. 7.1 shows two test-tubes, J and K, that a student set up to investigate the conditions needed for iron to rust. - . iron nail air water gauze drying agent removes water vapour Fig. 7.1 (i) Predict and explain in which test-tube, J or K, the nail rusted. Your explanation should include why the iron rusted in one of the tubes and not in the other. test-tube in which rust forms … explanation … … … …[2] (ii) Mild steel is an alloy of iron that forms rust. Describe how rust is prevented from forming on mild steel that is used to make large objects such as bicycle frames or car bodies. … …[1] (iii) Explain why the method you have described in (ii) prevents rust formation. … …[1]

15 0654/23/M/J/15 © UCLES 2015 [Turn over (b) Table 7.1 shows some of the physical and chemical properties of five oxides L to P. Table 7.1 oxide physical state at 20 °C colour pH after shaking with pure water L solid white 7 M solid red 7 N solid white 13 O solid white 1 P gas colourless 2 (i) State and explain which of the oxides have no effect on the pH of pure water when shaken with it. oxides … explanation … …[2] (ii) State and explain which of the oxides contains a transition metal. oxide … explanation … …[1] (iii) The elements calcium and phosphorus both form white, solid oxides. Use the information in Table 7.1 to deduce whether oxide O is calcium oxide or phosphorus oxide. Explain your answer. … … …[2]

16 0654/23/M/J/15 © UCLES 2015 (c) The burning of magnesium in air to form magnesium oxide is an exothermic reaction. (i) Construct the word chemical equation for this reaction. + [1] (ii) State the meaning of the term exothermic. … …[1] (iii) Name the salt that is produced when dilute sulfuric acid is neutralised by magnesium oxide. …[1]

17 0654/23/M/J/15 © UCLES 2015 [Turn over 8 (a) Coal is burned in a power station to generate electricity. Complete the sentences using suitable words to describe how this happens. Coal is burned to heat … in a boiler to produce steam. The steam drives a … , which turns a generator. [2] (b) Fig. 8.1 shows the energy transformations in a coal burning power station. electrical energy = 24 J input energy from fuel = 100 J energy transferred to the surroundings = 76 J Fig. 8.1 (i) State the form of energy contained in a fuel such as coal. … [1] (ii) State a form in which most energy is transferred to the surroundings. … [1] (iii) Explain how the information in Fig. 8.1 shows that the energy transfer from the fuel to electrical energy is not 100% efficient. … …[1]

18 0654/23/M/J/15 © UCLES 2015 (c) Some energy resources are shown. coal geothermal hydroelectricity nuclear oil solar energy wind energy Identify two resources that do not use the Sun as their source of energy. 1 … 2 … [1] (d) The workers in a nuclear power station must be protected from radioactive materials. (i) Explain why workers need protection from radioactive materials. … … …[2] (ii) Describe how enclosing the nuclear reactor in thick concrete protects the workers. … …[1] The combustion of fossil fuels may lead to global warming. (e) Name a gas produced by the combustion of fossil fuels that may lead to global warming. …[1] (f) Describe how global warming may affect (i) plants, … …[1] (ii) people living near the coast. … …[1] (g) Fossil fuels are non-renewable. Explain why it is important to conserve non-renewable resources. … …[1]

19 0654/23/M/J/15 © UCLES 2015 [Turn over Please turn over for Question 9.

20 0654/23/M/J/15 © UCLES 2015 9 Frederick Hopkins, a scientist, investigated the effect of diet on the growth of mice. He kept two groups of mice in a laboratory, feeding them on different diets. • Group 1 had a basic diet of purified protein, carbohydrate, fat and mineral ions. They also had plenty of water. • Group 2 had a supplemented diet. This was exactly the same as the basic diet, but with a small amount of milk added. Hopkins measured the average mass of the mice in each group over a period of 18 days. After 18 days, he reversed the diets. Fig. 9.1 shows his results. 0 10 40 50 60 70 80 90 20 30 40 50 average mass of animals / g day milk supplement started milk supplement stopped group  group  Fig. 9.1 (a) Compare the growth of the group 1 and group 2 animals between day 0 and day 9. Include in your answer how the growth of each group is alike and how the growth of each group is different. … … …[2]

21 0654/23/M/J/15 © UCLES 2015 [Turn over (b) State one function, in the diets, of (i) the protein, …[1] (ii) the carbohydrate. …[1] (c) Name one mineral ion that the mice would need in their diet, and state its function. mineral ion … function … …[2] (d) The basic diet lacked vitamins, such as vitamin D, but the supplemented diet contained these vitamins. Suggest how a lack of vitamin D would have affected the mice on the basic diet. … …[1] (e) In Hopkins’ experiment, the two groups of mice were treated in exactly the same way except for the food they were given. Explain why this was important. … …[1] (f) In the experiment, the diets were swapped after 18 days. Suggest what would have happened to the mice in group 1 if the diets had been swapped back again after 36 days. Give a reason for your answer. … … …[1] (g) Hopkins’ experiment was about nutrition, which is one of the seven characteristics of living organisms. State two other characteristics of living organisms. 1 … 2 …[2]

22 0654/23/M/J/15 © UCLES 2015 10 Many useful products are obtained from the fossil fuel, petroleum (crude oil). Before any useful products can be obtained, petroleum is first processed at an oil refinery. (a) Gasoline and diesel oil are fuels obtained from petroleum. Fig. 10.1 shows the industrial apparatus used to obtain gasoline and diesel oil from petroleum. gasoline diesel oil petroleum from storage tanks : Fig. 10.1 (i) Name the process shown in Fig. 10.1. …[1] (ii) State what happens to petroleum in the part of the apparatus labelled W. …[1]

23 0654/23/M/J/15 © UCLES 2015 [Turn over (iii) Fig. 10.2 shows one molecule of a compound found in gasoline and diesel oil. carbon atom NH\ hydrogen atom Fig. 10.2 Name the type of compound whose molecule is shown in Fig. 10.2. …[1] (iv) State the chemical formula of the molecule shown in Fig. 10.2. …[1] (b) Gasoline and diesel oil from the process in Fig. 10.1 contain dissolved sulfur compounds. (i) Name the gas that will be released into the air from car engines if sulfur compounds are not removed from these fuels before they are used. …[1] (ii) Describe some of the problems that the gas in (i) causes if it is released into the environment. … … … …[3]

24 0654/23/M/J/15 © UCLES 2015 11 (a) Define respiration. … … …[2] (b) Complete the word equation for aerobic respiration. + + carbon dioxide [2] (c) Fig. 11.1 shows apparatus that is used to demonstrate carbon dioxide production in a small mammal. Air is drawn through the apparatus by a pump. flask  flask  flask  limewater substance that removes carbon dioxide limewater Fig. 11.1 (i) On Fig. 11.1, draw arrows to indicate • where air enters the apparatus, • where air leaves the apparatus. [1]

25 0654/23/M/J/15 © UCLES 2015 [Turn over (ii) State the purpose of the limewater in flask 2, … … in flask 3. … … [2] (iii) Describe what will happen to the limewater in flasks 2 and 3 after air has been drawn through the apparatus for a few minutes. flask 2 … flask 3 …[2]

26 0654/23/M/J/15 © UCLES 2015 12 (a) Fig. 12.1 shows a speed / time graph over two minutes for a police car. 0 0 1 2 time / minutes speed m/s 10 20 30 40 Fig. 12.1 (i) Label with the letter X a point on the graph when the police car is not moving. [1] (ii) Label with the letter A a point on the graph where the car is accelerating. [1] (iii) Label with the letter K a point on the graph where the car has the most kinetic energy. [1] (b) The police car communicates with the police station using radio waves. The police car uses a flashing light to alert people. (i) Radio waves and light waves are both parts of the electromagnetic spectrum. Place radio waves and light waves in the correct boxes of the incomplete electromagnetic spectrum below. microwaves infra-red X-rays [2] (ii) Microwaves are used for heating and cooking food. State one other use for microwaves. …[1]

27 0654/23/M/J/15 © UCLES 2015 (iii) State one difference between the properties of radio waves and light waves. … …[1] (iv) Fig. 12.2 shows a wave. $ % & ' ( Fig. 12.2 State which measurement, A, B, C, D or E, is the amplitude of the wave, … the wavelength of the wave. … [2] (c) The bodywork of the police car is made from steel. The bodywork of some vehicles is made from aluminium. Suggest a simple way of deciding whether the bodywork of a vehicle is made from steel or aluminium. … …[1]

28 0654/23/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 0654 CO-ORDINATED SCIENCES 0654 / 23 Paper 2 (Core Theory), maximum raw mark 120 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 0654 23 © Cambridge International Examinations 2015 1 (a) element group in Periodic Table group name reactive / unreactive electrical conductor / insulator A (1) (alkali metals) (reactive) conductor B (7) (halogens) reactive insulator C (0) noble/inert gases unreactive (insulator) (1 for each column) ; ; ; [3] (b) proton number / protons in the nucleus ; [1] (c) (i) (X) number of neutrons in X is 10 – 5 = 5 / or similar statement ; [1] (ii) isotopes / nuclides ; [1] (d) (i) hydrogen ; [1] (ii) increases ; an alkali / sodium hydroxide is produced ; [2] (iii) slower evolution of gas / less exothermic / takes longer for lithium to react completely ; because lithium is less reactive / higher up Group 1 ; [2] [Total: 11] 2 (a) (i) all symbols correct ; all in series ; [2] (ii) (current) = voltage / resistance ; = 4.5 / 5 = 0.9 ; A / ampere ; [3] (iii) 10 Ω ; [1] (b) (i) (angle of) incidence ; [1] (ii) (angle of) reflection ; [1] (iii) angle C will double ; [1] [Total: 9]

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – May / June 2015 0654 23 © Cambridge International Examinations 2015 3 (a) (i) 2002 ; [1] (ii) not diagnosed / people not seeing a doctor ; [1] (b) sex ; exchange of sexual fluids needle sharing (contaminated) blood transfusions ; mother to baby [max 2] (c) (i) decreases ; from 5800 to 3100 / by 2700 / to about half ; [2] (ii) better education ; screening blood transfusions ; use of condoms ; free needles for drug addicts ; AVP ; [max 2] [Total: 8] 4 (a) (i) electrons ; [1] (ii) move apart / repel ; because like charges repel each other ; [2] (b) (i) sound waves are reflected ; [1] (ii) 166 m ; [1] (iii) speed = distance / time ; = 166 / 0.5 = 332 m / s ; allow ecf [2] (c) gases contract when cooled ; gas particles move more slowly when cooled / have less energy ; particles exert less pressure on balloon walls / hit walls less frequently / energetically ; particles are close(r) together ; [max 2] (d) (i) upward force is greater than downward force / resultant upward force ; [1] (ii) density = mass / volume ; =2660 / 2800 = 0.95 kg / m3 ; [2] [Total: 12]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – May / June 2015 0654 23 © Cambridge International Examinations 2015 5 (a) heat ; leave for rest of water to evaporate ; [2] (b) (i) so it has equal numbers of protons and electrons ; so their charges are balanced / cancel out / protons have positive charge and electrons have negative charge ; because it has a larger number of protons than electrons ; [3] (ii) (sodium and chloride) ions have opposite electrical charges / opposite charges attract ; [1] (c) (i) electrolysis ; [1] (ii) oppositely charged / cathode is negative and anode is positive ; [1] (iii) hydrogen ; [1] [Total: 9] 6 (a) (i) transpiration ; [1] (ii) arrow labelling the surface of a cell in contact with the air ; [1] (iii) stoma / stomata ; [1] (iv) high temperature ; low humidity ; arid / dry air movements / winds light ; [max 2] (b) (i) palisade / mesophyll / cells Q ; many chloroplasts ; [2] (ii) entry of CO2 ; [1] [Total: 8] 7 (a) (i) (K) no mark (rusting requires) air / oxygen and water present (together) ; correct ref. to O and H2O test-tube J contains no water ; [2] (ii) painted / (chrome) plating / enamelling / etc. ; [1] (iii) idea that paint (etc.) forms as a barrier to air / oxygen and water ; [1]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – May / June 2015 0654 23 © Cambridge International Examinations 2015 (b) (i) L and M ; the pH of water is 7 ; [2] (ii) (M) no mark transition metals form coloured oxides / the oxide is red ; ; [1] (iii) (phosphorous oxide) no mark forms an acidic oxide ; is a non-metal oxide / phosphorus is a non-metal ; ; [2] (c) (i) magnesium + oxygen → magnesium oxide ; [1] (ii) thermal energy / heat given out / temperature increases (during reaction) ; [1] (iii) magnesium sulphate ; [1] [Total: 12] 8 (a) water ; turbine ; [2] (b) (i) chemical ; [1] (ii) sound or thermal / heat ; [1] (iii) some energy is lost / not all energy input changed into electrical energy ; [1] (c) geothermal and nuclear ; [1] (d) (i) radiation is ionising ; ionising radiation causes cancer in humans, etc. ; [2] (ii) radiation cannot penetrate thick concrete ; [1] (e) carbon dioxide / water vapour ; [1] (f) (i) too dry / too wet / too warm / need to move to cooler habitat ; [1] (ii) flooding / loss of land ; [1] (g) cannot be replaced once used ; [1] [Total: 13]

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – May / June 2015 0654 23 © Cambridge International Examinations 2015 9 (a) both increasing ; Group 2 increasing faster ; [2] (b) (i) growth / repair ; [1] (ii) energy ; [1] (c) calcium ; for bones ; or iron ; for blood ; [2] (d) poor bone growth ; [1] (e) no other variables / fair test ; [1] (f) they grow more slowly, because no milk / vitamins ; or continue to grow for a while as Group 2 did / because no milk / vitamins ; [1] (g) movement ; respiration ; sensitivity ; growth ; reproduction ; excretion ; [max 2] [Total: 11] 10 (a) (i) fractional distillation / fractionation ; [1] (ii) heated / boiled ; [1] (iii) hydrocarbon / alkane ; [1] (iv) C8 H18 ; [1] (b) (i) sulfur dioxide ; [1] (ii) causes acid rain ; harms animal / plant life ; causes corrosion of metals / stonework ; may cause breathing difficulties / asthma / irritate respiratory system ; [max 3] [Total: 8]

Page 7 Mark Scheme Syllabus Paper Cambridge IGCSE – May / June 2015 0654 23 © Cambridge International Examinations 2015 11 (a) chemical reactions ; breaking down nutrient molecules ; in cells ; releasing energy ; [1] (b) glucose + oxygen (on the left) ; water (on the right) ; [1] (c) (i) arrows on diagram – in on the left, out on the right ; [2] (ii) (flask 2) to show no CO2 in incoming air ; (flask 3) to show CO2 produced by animal ; [1] (iii) one clear, one milky ; flask 2 clear, flask 3 milky ; [1] [Total: 9] 12 (a) (i) X at two minutes ; [1] (ii) A written anywhere on section from 1.5 min – 2 mins ; [1] (iii) K written anywhere on section from 0 mins – 1.5 mins ; [1] (b) (i) radio waves first box ; visible light fourth box ; [2] (ii) satellite TV / mobile phone communication ; [1] (iii) frequency or wavelength ; [1] (iv) B ; E ; [2] (c) use a magnet – steel will be attracted / steel is magnetic and aluminium will not be attracted / aluminium is not magnetic ; [1] [Total: 10]