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

This document consists of 30 printed pages and 2 blank pages. DC (RW/SW) 110308/5 © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 5 2 5 5 6 5 3 7 7 4 * CO-ORDINATED SCIENCES 0654/22 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 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 0654/22/M/J/16 © UCLES 2016 1 A student adds dilute hydrochloric acid to four solids. Fig. 1.1 shows the four experiments A, B, C and D. dilute hydrochloric acid A B C D dilute hydrochloric acid dilute hydrochloric acid dilute hydrochloric acid sodium hydrogencarbonate calcium carbonate magnesium copper Fig. 1.1 (a) (i) In experiments B and D the same gas is released. Name this gas and describe a test for it. name of gas … test … … [2] (ii) Name both products of the reaction in experiment C. 1 … 2 … [2]

3 0654/22/M/J/16 © UCLES 2016 [Turn over (b) Table 1.1 shows temperature measurements the student makes during his investigation. Table 1.1 experiment temperature of substances before mixing / °C temperature of the mixture after one minute / °C A 22 22 B 22 24 C 22 45 D 22 15 (i) Give the letter of the experiment that involves an exothermic reaction. Explain your answer. reaction … explanation … … [1] (ii) Explain the results for experiment A. … … …[2] (c) Nitrogen combines with oxygen to form nitrous oxide, N2O. Nitrogen combines with magnesium to form magnesium nitride, Mg3N2. Predict the type of chemical bonding in nitrous oxide and magnesium nitride. In each case give a reason for your answer. bonding in nitrous oxide … reason … bonding in magnesium nitride … reason … [4]

4 0654/22/M/J/16 © UCLES 2016 2 (a) Plants lose water by evaporation. (i) Name the part of the plant from which most of this evaporation occurs. …[1] (ii) State the term for the loss of water from a plant by evaporation. …[1] (b) Fig. 2.1 shows the rate of water loss and the rate of water uptake for a plant over a period of one day. 00:00 0 10 20 30 40 04:00 08:00 12:00 16:00 20:00 time / hours water / g per hour 24:00 water loss water uptake Fig. 2.1 (i) For this day, state the time at which the rate of water loss is greatest, … a time when the rate of water loss is the same as the rate of water uptake. … [2]

5 0654/22/M/J/16 © UCLES 2016 [Turn over (ii) Describe the relationship between water loss and water uptake that is shown in Fig. 2.1. … … …[2] (c) State one way in which plants use water in (i) palisade mesophyll cells, …[1] (ii) xylem vessels. …[1]

6 0654/22/M/J/16 © UCLES 2016 3 Fig. 3.1 shows an aircraft moving with constant acceleration from rest along a runway. Fig. 3.1 (a) After 30 seconds the aircraft reaches a speed of 60 m / s. On the grid below draw a speed / time graph to show the motion of the aircraft during this 30 second period. 0 0 10 20 30 40 50 60 70 80 10 20 30 time / s speed m / s 40 [2] (b) (i) Just after taking off, the aircraft continues to accelerate as it gains height. State the term used to describe the energy gained by the aircraft. …[1] (ii) State the term used to describe the energy contained in the aircraft’s fuel. …[1]

7 0654/22/M/J/16 © UCLES 2016 [Turn over (c) Fig. 3.2 shows a different aircraft moving at constant speed along the runway. S Q R P Fig. 3.2 Four forces P, Q, R and S are shown. (i) State which force from P, Q, R and S is the weight of the aircraft, … the force exerted by the thrust of the engines. … [2] (ii) Compare the sizes of forces Q and S. … …[1] (d) Fig. 3.3 shows an aircraft being refuelled through a rubber pipe. aircraft rubber pipe tanker Fig. 3.3 As the fuel flows through the rubber pipe it becomes negatively charged. Suggest, in terms of electrons, why the fuel becomes negatively charged. … …[2]

8 0654/22/M/J/16 © UCLES 2016 4 Fig. 4.1 shows a hot-air balloon and a helium-filled airship. The air in the balloon is heated by burning the hydrocarbon gas propane. propane gas burner hot-air balloon helium-filled airship Fig. 4.1 (a) (i) State the percentages of nitrogen and oxygen in unpolluted air. oxygen …% nitrogen …% [2] (ii) The composition of the hot gas mixture inside the hot-air balloon is different from that of the air outside. How is the air different? Explain your answer. … … …[2]

9 0654/22/M/J/16 © UCLES 2016 [Turn over (b) Propane is obtained from a fossil fuel. (i) Complete the sentences below using words or phrases chosen from the list. Each word or phrase may be used once, more than once or not at all. catalytic cracking compound fractional distillation gas liquid mixture polymerisation solid Propane is obtained from petroleum by the process of … Propane has a chemical formula because it is a … Petroleum does not have a chemical formula because it is a … [3] (ii) Propane is a saturated hydrocarbon. State the meaning of the term saturated hydrocarbon. … … …[2] (c) Both helium and hydrogen can be used to fill airships. Give one reason why helium is preferred to hydrogen for filling airships designed to transport people. … …[1]

10 0654/22/M/J/16 © UCLES 2016 5 Table 5.1 shows the area of deforestation in four different countries in a five year period. Table 5.1 country area of deforestation in five years / km2 F 28 000 G 9500 H 1500 J 500 (a) For the four countries combined, calculate the average area of deforestation per year during this five year period. average deforestation per year … km2 [2] (b) A student concluded that deforestation is more of a problem in country F than in country G. State two other pieces of information that are needed to make this comparison. 1 … 2 … [2] (c) (i) Suggest two reasons why people might cut down a large number of trees. 1 … 2 … [2] (ii) State two possible harmful effects of cutting down a large number of trees. 1 … 2 … [2]

11 0654/22/M/J/16 © UCLES 2016 [Turn over 6 (a) Fig. 6.1 shows an incomplete diagram of the electromagnetic spectrum. UDGLR ZDYHV XOWUDYLROHW JDPPD UDGLDWLRQ Fig. 6.1 (i) Visible light is part of the electromagnetic spectrum. On Fig. 6.1 write visible light in the correct position. [1] (ii) State the part of the electromagnetic spectrum shown in Fig. 6.1 which has the highest frequency. …[1] (b) Gamma radiation is emitted from some unstable nuclei. Gamma radiation is ionising. (i) State what is meant by the term ionising radiation. … …[1] (ii) State one risk to humans of exposure to ionising radiation. …[1] (iii) Alpha radiation is also emitted from some unstable nuclei. State two differences between gamma radiation and alpha radiation. 1 … … 2 … … [2]

12 0654/22/M/J/16 © UCLES 2016 (c) Fig. 6.2 represents a wave. A C E B D Fig. 6.2 State which measurement A, B, C, D or E is (i) the amplitude of the wave, … [1] (ii) the wavelength of the wave. … [1] (d) Visible light is able to pass through an optical fibre by total internal reflection. Fig. 6.3 shows a student’s diagram of total internal reflection along an optical fibre. The diagram contains some errors. Fig. 6.3 On Fig. 6.3, circle one error the student has made in their diagram. Describe the error you have identified. … … … [2]

13 0654/22/M/J/16 © UCLES 2016 [Turn over (e) A converging lens is used to produce an image of a candle. Fig. 6.4 shows the rays of light from the top of the candle passing through the lens and being focussed on the screen. candle image Fig. 6.4 (not to scale) (i) On Fig. 6.4, label with an F, the principal focus of the lens. [1] (ii) On Fig. 6.4, use a double headed arrow ( ) to show the focal length of the lens. [1]

14 0654/22/M/J/16 © UCLES 2016 7 (a) Define the term homeostasis. … … …[2] (b) Fig. 7.1 shows a cross-section of the skin. K M L Fig. 7.1 (i) Name the structures labelled K and L. K … L … [2] (ii) State what type of tissue is found at M. …[1]

15 0654/22/M/J/16 © UCLES 2016 [Turn over (iii) Use the words in the list to complete the sentences about temperature control. Each word may be used once, more than once, or not at all. arterioles capillaries insulation muscles vasoconstriction vasodilation veins When a person is too cold, the … near the surface of their skin contract. This is called … , and it results in reduced blood flow through the … near the surface of the skin. [3]

16 0654/22/M/J/16 © UCLES 2016 8 Fig. 8.1 shows a car. Fig. 8.1 (a) The car travels 70 km in 1.2 hours. Calculate the average speed of the car in km / h. State the formula you use and show your working. formula working speed = … km / h [2] (b) The car is left outside on a hot, sunny day. (i) State the method of energy transfer by which energy travels from the Sun to the Earth. …[1] (ii) The air in the tyres of the car also gets hot. Explain, in terms of particles, why the pressure of the air in the tyres increases as the air gets hot. … … …[2]

17 0654/22/M/J/16 © UCLES 2016 [Turn over (c) On a very cold morning there is ice on the windscreen of the car. The ice disappears as the air temperature increases above the melting point of the ice. State what is meant by the term melting point. … …[2] (d) The wheels of some cars are made from an alloy of aluminium. Steel can also be used to make the wheels. Suggest a simple way for the owner to test whether a wheel from the car is made from aluminium or steel. Explain your answer. … …[1] (e) The engine in the car is noisy. The driver can hear the sound from the engine because the frequency of the sound is within the human audible frequency range. (i) State the audible frequency range for a normal adult human. from … Hz to … Hz [2] (ii) The driver notices that the sound from the engine is very loud and has a high pitch. Describe the frequency of this sound. … …[1]

18 0654/22/M/J/16 © UCLES 2016 9 (a) (i) Explain the meaning of the following statements about the element lead. The proton number of lead is 82. … … The nucleon number of a lead atom is 207. … … [2] (ii) Another atom of lead has a nucleon number of 208. State the term used for atoms of an element that have different nucleon numbers. … [1] (b) Fig. 9.1 shows the apparatus and materials a teacher assembles for the electrolysis of lead bromide. – d.c. power supply + crucible lead bromide powder Fig. 9.1 (i) On Fig. 9.1, label the cathode. [1] (ii) When the teacher closes the switch in his circuit, electrolysis does not occur. Describe what the teacher must do so that the electrolysis does occur. …[1]

19 0654/22/M/J/16 © UCLES 2016 [Turn over (iii) Name the gas that would be produced during this electrolysis and state the colour of this gas. name of gas … colour of gas … [2] (c) Fig. 9.2 shows the apparatus and materials used to investigate the reaction between lithium and water. pH meter pH lithium gas given off water lithium hydroxide dissolves Fig. 9.2 The reaction between lithium and water produces a gas and a solution of lithium hydroxide, LiOH. (i) Suggest and explain the reading of the pH meter at the end of the reaction. pH reading … explanation … … [2] (ii) Name the gas that is given off during the reaction. …[1]

20 0654/22/M/J/16 © UCLES 2016 (iii) Lithium hydroxide is used in space vehicles to remove the carbon dioxide produced by the astronauts. Gaseous carbon dioxide reacts with lithium hydroxide to produce lithium carbonate. Water is also produced in the reaction. Construct the word equation for this reaction. … + … … + … [1]

21 0654/22/M/J/16 © UCLES 2016 [Turn over Please turn over for Question 10.

22 0654/22/M/J/16 © UCLES 2016 10 Cystic fibrosis (CF) is a genetic disorder caused by a recessive allele. (a) State what is meant by the term recessive allele. … … …[2] (b) Fig. 10.1 shows the inheritance of cystic fibrosis in a family. = normal male NH\ 3 JUDQGSDUHQWV SDUHQWV RIIVSULQJ 6 5 4 = male with CF = normal female = female with CF Fig. 10.1 Using the symbols N (allele for normal) and n (allele for CF), state all the possible genotypes of the people labelled P, Q and R. P … Q … R … [4]

23 0654/22/M/J/16 © UCLES 2016 [Turn over (c) The person labelled S has a normal phenotype. (i) State what is meant by the term phenotype. … …[1] (ii) Person S is heterozygous. Explain what this means. …[1]

24 0654/22/M/J/16 © UCLES 2016 11 Sulfur is a yellow, crystalline solid that is often found uncombined in the Earth’s crust. (a) Fig. 11.1 shows the arrangement of atoms in sulfur crystals. sulfur atom chemical bond key Fig. 11.1 (i) State the word used for a small group of atoms that are chemically bonded. …[1] (ii) State the chemical formula of the structure shown in Fig. 11.1. …[1]

25 0654/22/M/J/16 © UCLES 2016 [Turn over (b) Fig. 11.2 shows the apparatus and materials used by a teacher to demonstrate the formation of sulfur dioxide by burning sulfur in air. water gas-jar air sulfur burning Fig. 11.2 (i) When sulfur burns it is oxidised. Explain why sulfur is said to be oxidised in this reaction. … …[1] (ii) Some sulfur dioxide dissolves and reacts with the water in the bottom of the gas-jar to form an aqueous solution. Predict and explain the colour of full-range indicator (Universal Indicator) when added to this aqueous solution. colour … explanation … … [2] (iii) Sulfur compounds occur naturally in petroleum. These are removed before petroleum products, such as gasoline, are used as fuel. State and explain, in terms of the effects on the environment, why sulfur compounds are removed from petroleum. … … … … …[3]

26 0654/22/M/J/16 © UCLES 2016 12 A torch contains four cells, a filament lamp and a switch connected in series. (a) (i) Draw a circuit diagram for the torch using electrical circuit symbols. [3] (ii) A voltmeter is used to check the potential difference (voltage) across the lamp. The symbol for the voltmeter is V Using the symbol for a voltmeter, draw the voltmeter connected in the correct position in the circuit you have drawn in (a)(i). [1] (b) The current in the filament lamp and the potential difference (voltage) across the lamp are measured. Fig. 12.1 shows the current / potential difference graph for the lamp. 0 0 0.2 0.4 0.6 0.8 1 2 3 4 5 potential difference / V current / A 6 Fig. 12.1

27 0654/22/M/J/16 © UCLES 2016 [Turn over (i) State how the graph in Fig. 12.1 shows that current in the lamp is not proportional to the potential difference across the lamp. … …[1] (ii) Use the graph in Fig. 12.1 to find the current through the lamp when the potential difference across the lamp is 6 V. current = … A [1] (c) Two lamps, one of resistance 4 Ω and one of resistance 12 Ω, are connected in series. Calculate the total resistance of these two lamps in series. State the formula you use and show your working. formula working resistance = … Ω [2]

28 0654/22/M/J/16 © UCLES 2016 13 (a) A piece of tissue from a plant root is tested for reducing sugar. Outline how this test is done and state the result of the test if reducing sugar is present. … … …[3] (b) Fig. 13.1 shows a root cell from a piece of tissue. Fig. 13.1 (i) For this root cell, name a structure that contains chromosomes, … a structure that would not be present in an animal cell, … a structure that is not present, but which would be present in a palisade cell. … [3] (ii) An animal eats this root. State which structure in the plant cell contributes fibre to the animal’s diet. …[1]

29 0654/22/M/J/16 © UCLES 2016 (iii) State how fibre is important in the diet of the animal. … …[1]

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32 0654/22/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 0654/22 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 22 © Cambridge International Examinations 2016 1 (a) (i) carbon dioxide ; reference to limewater ; [2] (ii) magnesium chloride ; hydrogen ; [2] (b) (i) (B or C) (reaction causes) temperature increase ; [1] (ii) no change in temperature (suggests) no reaction ; because copper (too) unreactive (to displace hydrogen from dilute acid) ; [2] (c) nitrous oxide covalent ; compound of two non-metals ; magnesium nitride ionic / eletrovalent ; compound of metal and non-metal ; [4] [Total: 11] 2 (a) (i) leaves / stomata / mesophyll surface ; [1] (ii) transpiration ; [1] (b) (i) 15.30–16.30 ; 17.00 ; [2] (ii) similar pattern / correlated ; water uptake lags behind water loss ; appropriate ref to figures in the graph ; [max 2] (c) (i) photosynthesis / turgor / support / solvent ; [1] (ii) transported / transports ions in solution ; [1] [Total: 8] 3 (a) straight line ; from (0, 0) to (30, 60) ; [2] (b) (i) kinetic energy / (gravitational) potential energy ; [1] (ii) chemical energy ; [1] (c) (i) R ; Q ; [2] (ii) equal and opposite ; [1]

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 22 © Cambridge International Examinations 2016 (d) friction between fuel and pipe ; electrons transferred ; from pipe to fuel ; [max 2] [Total: 9] 4 (a) (i) oxygen 21 (%) ; nitrogen 78 (%) ; [2] (ii) reference to the combustion products of propane / hydrocarbons which rise into balloon mixing with air inside ; higher amounts of CO2 / CO / H2O ; so lower amounts of oxygen ; [max 2] (b) (i) fractional distillation ; compound ; mixture ; [3] (ii) compound containing only hydrogen and carbon ; having only single bonds / containing as much hydrogen as possible / no double bonds ; [2] (c) reference to helium being unreactive / greater reactivity of hydrogen / reference to safety / reducing fire risk ; [1] [Total: 10] 5 (a) total = 39 500 ; ÷ 5 = 7900 ; [2] (b) area of the country ; area of the forest ; any replanting (elsewhere) ; [max 2] (c) (i) use land for agriculture / building / mining ; for fuel ; use wood for construction etc. ; [max 2] (ii) extinction ; loss of animal habitat ; disruption of food chains / webs ; loss of soil ; flooding ; increased CO2 (in atmosphere) ; [max 2] [Total: 8]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 22 © Cambridge International Examinations 2016 6 (a) (i) visible placed to left of UV ; [1] (ii) right hand side / gamma end ; [1] (b) (i) radiation that causes atoms / molecules to ionise / lose electrons ; [1] (ii) cancer / mutations ; etc. [1] (iii) gamma more penetrating ; gamma has no charge, alpha has (positive) charge ; gamma is a wave, alpha is a particle ; gamma less ionising ; [max 2] (c) (i) B ; [1] (ii) E ; [1] (d) error labelled ; not total internal reflection / wave leaves fibre / angles of incidence and reflection not equal ; [2] (e) (i) principal focus correctly labelled ; [1] (ii) focal length correctly shown ; [1] [Total: 12] 7 (a) maintaining constant ; internal environment ; [2] (b) (i) K = (named type of) receptor ; L = sweat gland ; [2] (ii) fat(ty) ; [1] (iii) arterioles ; vasoconstriction ; capillaries ; [3] [Total: 8] 8 (a) (speed =) distance / time or 70 / 1.2 ; = 58.3(3) (km / hr) ; [2] (b) (i) radiation ; [1]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 22 © Cambridge International Examinations 2016 (ii) particles move faster / have more KE ; collide with type walls more often / hit tyre wall harder / with greater force ; [2] (c) the temperature at which ; a solid turns into a liquid ; [2] (d) use a magnet – steel as magnetic ; [1] (e) (i) 20 (allow 10) (Hz) ; to 20 000 (allow 25 000) (Hz) ; [2] (ii) high frequency ; [1] [Total: 11] 9 (a) (i) a lead atom / nucleus contains 82 protons ; the total number of particles in the atom / nucleus is 207 / the total number of protons + neutrons in the lead atom is 207 ; [2] (ii) isotopes ; [1] (b) (i) label line goes to the negative electrode and nowhere else ; [1] (ii) melt the lead bromide ; [1] (iii) bromine is produced ; orange / brown ; [2] (c) (i) 8 to 14 ; lithium hydroxide solution is alkaline [2] (ii) hydrogen ; [1] (iii) lithium hydroxide + carbon dioxide → lithium carbonate + water ; [1] [Total: 11] 10 (a) two or more alternative forms of a gene ; only expressed when dominant allele is not present / not expressed when dominant allele is present / needs two present to show / not expressed when heterozygous ; [2]

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 22 © Cambridge International Examinations 2016 (b) P = Nn ; Q = NN ; or Nn ; R = nn ; [4] (c) (i) (the physical or other) features / characteristics of an organism (due to both its genotype and environment ; [1] (ii) has genotype Nn / contains two different alleles ; [1] [Total: 8] 11 (a) (i) molecule ; [1] (ii) S8 ; [1] (b) (i) reference to gain of oxygen (by sulfur atoms) ; [1] (ii) red / orange ; solution is acidic / sulfur dioxide is acidic / non-metal oxides are acidic ; [2] (iii) reference to formation of sulfur dioxide ; sulfur dioxide reacts forming acid rain ; acid rain causes chemical damage to buildings ; biological damage to plant / animal life ; sulfur dioxide poses health risks for humans ; [max 3] [Total: 8] 12 (a) (i) all components present and the correct number; in series circuit ; all symbols correct ; [3] (ii) voltmeter (correct symbol) connected in parallel across lamp ; [1] (b) (i) not a straight line ; [1] (ii) 0.7 (A) ; [1] (c) RT = R1 + R2 or 4 + 12 ; RT = 16 (Ω) ; [2] [Total: 8] 13 (a) add Benedict’s solution ; heat ; red (precipitate) ; [3]

Page 7 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 22 © Cambridge International Examinations 2016 (b) (i) nucleus ; cell wall ; chloroplast ; [3] (ii) cell wall ; [1] (iii) prevents constipation ; [1] [Total: 8]