Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2013 Oct/Nov Paper 2 · Variant 3

This document consists of 28 printed pages. IB13 11_0654_23/3RP © UCLES 2013 [Turn over *2732146244* UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education CO-ORDINATED SCIENCES 0654/23 Paper 2 (Core) October/November 2013 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 a 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 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 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 1 Fig. 1.1 shows a root hair cell. Fig. 1.1 (a) Use the letters A, B and C to label these parts of the root hair cell in Fig. 1.1. A the cell membrane B the part that contains chromosomes C a structure that is not present in animal cells [3] (b) Name two substances that are absorbed by root hair cells. 1 2 [2]

3 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (c) Fig. 1.2 shows part of a plant stem from which the outer layer, including the phloem, has been removed. xylem phloem Fig. 1.2 (i) State the function of phloem. [2] (ii) Suggest why this treatment would cause the roots of the plant to die. [2]

4 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 2 (a) Table 2.1 shows information about some chemical elements and their positions in the Periodic Table. Table 2.1 element group number in the Periodic Table oxygen 6 calcium 2 lithium 1 sulfur 6 fluorine 7 (i) State the noble (inert) gas that is in the same period of the Periodic Table as sulfur. [1] (ii) Select two elements from Table 2.1 whose atoms form ionic chemical bonds with each other and explain your answer. and explanation [2] (b) Fig. 2.1 shows a diagram of an atom. A Fig. 2.1 (i) Name structure A in Fig. 2.1. [1]

5 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (ii) State the proton number of the atom in Fig. 2.1. Explain your answer briefly. proton number explanation [2] (c) A student added excess acidified barium chloride solution to a solution of a magnesium compound to produce mixture W. Fig. 2.2 shows the procedure followed. mixture W white precipitate settled on the bottom of the beaker solution of a magnesium compound acidified barium chloride solution Fig. 2.2 (i) Suggest the full name of the magnesium compound in the original solution. [1] (ii) Describe briefly what the student should do to find the mass of the white precipitate in mixture W. [3]

6 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 3 (a) Fig. 3.1 shows a circuit used to measure the current passing through a resistor when the voltage across it is changed. meter X meter Y component Z R Fig. 3.1 (i) Describe the purpose of component Z in the circuit. [1] (ii) The meters shown in the circuit give readings of 0.6 A and 8.0 V. State which meter, X or Y, gives the reading of 0.6 A. Explain your answer. meter explanation [1] (iii) Calculate the resistance of resistor R. State the formula that you use and show your working. formula working Ω [2]

7 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (b) Complete the sentences below using a word or phrase from the list. Each word or phrase can be used once, more than once or not at all. decreases increases is zero stays the same When the voltage across the resistor is reduced, the current through the resistor . When the voltage of the supply is reduced, the voltage across the resistor . When the voltage across the resistor is reduced, the resistance of the wire . [2] (c) The resistance of a piece of wire depends on a number of variables such as the temperature of the wire and the material from which it is made. State two other factors which affect the resistance of a piece of wire. 1 2 [2]

8 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 4 Soya beans are an important crop in Brazil. Soya beans contain a lot of protein, plus smaller quantities of starch and fat. (a) Describe how you could test a sample of soya beans to find out if they contain fat. [3] (b) Explain why protein is an important part of a balanced diet. [2] (c) When a person eats soya beans, the beans are chewed in the mouth. Explain why this makes it easier for enzymes in the digestive system to digest the beans. [2] (d) Raw soya beans contain substances that stop protease enzymes from working. Cooking destroys these substances. Suggest how eating uncooked soya beans could prevent the absorption of some of the nutrients from them. [2]

9 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (e) Large areas of rainforest have been cleared in Brazil, to provide more land for growing soya beans. Explain how cutting down the rainforest can harm the environment. [4]

10 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 5 (a) A student placed four equally-sized pieces of different metals into colourless liquids contained in four test-tubes P, Q, R and S. Fig. 5.1 shows what the student observed. P gas produced slowly Q no gas produced orange layer forms on metal surface after several days R gas produced quickly S no reaction Fig. 5.1 (i) Suggest which of the test-tubes in Fig. 5.1 contained water to which a piece of iron was added. Explain your answer. test-tube explanation [3] (ii) The colourless liquid in test-tube R was dilute hydrochloric acid. Suggest the name of the metal that was added to test-tube R and name the gas that was produced. metal gas [2] (iii) Test-tube P contained the same concentration of dilute hydrochloric acid at the same temperature as test-tube R. Suggest the name of the metal that was added to test-tube P. [1]

11 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (b) In the process of copper plating, a thin layer of copper is formed on the surface of a metal object. Fig. 5.2 shows the apparatus and materials that are needed to copper plate a metal key. copper sulfate solution + – d.c. power supply pair of connecting wires copper electrode metal key Fig. 5.2 Draw a diagram which shows how the apparatus and materials in Fig. 5.2 should be assembled so that the metal key will be copper plated. [3]

12 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 6 (a) Fig. 6.1 gives information about the uses of different types of electromagnetic waves and their effects on living tissue. Draw lines to link each electromagnetic wave with its effect on living tissue and its use. One has been completed as an example. screening luggage security marking satellite communication seeing uses X-rays microwave ultra violet visible light type of radiation activates sensitive cells in retina kills cancerous cells heats water in tissues causes tanning of skin effects on tissue Fig. 6.1 [4] (b) Electromagnetic waves are transverse waves. Water waves are also transverse. Draw a diagram of a transverse wave on the axes below. Label the amplitude and one wavelength on your diagram. [3]

13 © UCLES 2013 0654/23/O/N/13 [Turn over Please turn over for Question 7.

14 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 7 Ball pythons (royal pythons) are snakes that are kept as pets in many parts of the world. The colour of a ball python is determined by its genes. Some ball pythons are albino (white). This is caused by a recessive allele, a. The dominant allele, A, gives normal colouring. (a) Complete Table 7.1 to show the possible genotypes and colours arising from this gene. Table 7.1 genotype colour AA Aa normal albino [2] (b) State the correct biological term for the visible appearance produced by the genotype, in this case the colour of the snake. [1]

15 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (c) (i) Complete the genetic diagram to explain the results of crossing two snakes that are heterozygous for these alleles. … and … and and genotype of parents gametes gametes from one parent gametes from the other parent [3] (ii) State the ratio of offspring that you would expect from this cross. ratio of normal : albino offspring = : [1] (d) A breeder has several snakes with normal colouring. Suggest how she can find out whether a particular snake is homozygous or heterozygous. [2]

16 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 8 (a) Fig. 8.1 shows apparatus a student used to investigate the reaction between dilute nitric acid and excess calcium carbonate. dilute nitric acid calcium carbonate Fig. 8.1 (i) Name the gas that is given off in this reaction. [1] (ii) Describe how the student could test for the gas you named in (i). You may wish to complete the diagram in Fig. 8.1 to help you to answer this question. [2] (iii) At the end of the reaction the test-tube in Fig. 8.1 contains a solution of the compound calcium nitrate. State the general name for compounds like calcium nitrate which are produced when an acid reacts with a metal carbonate. [1] (iv) The chemical formula of calcium nitrate is Ca(NO3)2. State the total number of atoms and the number of different elements that are shown combined together in this formula. total number of atoms number of different elements [2]

17 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (b) The student then carried out an investigation into the way that the rate of the reaction in (a) changed when he varied the concentration of the nitric acid. Fig. 8.2 shows the apparatus the student used to measure the rate of reaction. excess dilute nitric acid calcium carbonate piston of the syringe slides out as gas enters gas syringe Fig. 8.2 The student measured the rate of reaction by finding how long it took for the gas syringe to fill with gas. (i) After he had completed several measurements, the student wrote the following correct conclusion in his notebook. Conclusion The higher the pH of the dilute nitric acid the longer it took for the gas syringe to fill with gas. Explain this conclusion briefly. [2] (ii) State two other variables that can affect the rate of reaction between dilute nitric acid and calcium carbonate. 1 2 [2]

18 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 9 Fig. 9.1 shows a solar-powered golf cart used to carry golfers around a golf course. Fig. 9.1 (a) As the cart moves around the course, the motion of the cart is measured. Fig. 9.2 shows a distance / time graph for a small part of the journey lasting 60 seconds. 100 80 60 40 20 0 0 10 20 30 time / s 40 50 60 distance / m A B C D E F E D C B A Fig. 9.2 (i) Write down the total distance covered in 60 s. m [1]

19 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (ii) Calculate the speed of the cart between B and C. Show your working. m / s [1] (iii) Describe the motion of the cart between D and E. [1] (iv) During another part of the journey, the cart is accelerating. State whether the forces acting on the cart are balanced or unbalanced. Explain your answer. [1] (b) The cart is powered by solar cells on its roof. The solar cells produce electrical energy used to charge the rechargeable batteries in the cart. Name one other renewable energy resource that could produce electrical energy. [1] (c) The golfer hits a golf ball with his club. The ball flies through the air. (i) State the form of energy given to the golf ball when the ball is hit. [1] (ii) State the form of energy gained by the golf ball as it rises into the air after being hit. [1]

20 © UCLES 2013 0654/23/O/N/13 For Examiner's Use (d) The mass of a golf ball is 45 g. The volume of a golf ball is 36 cm3. Calculate the density of the golf ball. State the formula that you use and show your working. formula working g / cm3 [2] (e) (i) The head of the golf club is made of solid metal. The air that the golf ball is travelling through is a gas. Complete Fig. 9.3 below to show the arrangement of particles in a gas. The diagram for a solid has been done for you. solid gas Fig. 9.3 [2] (ii) During the cart’s journey, the temperature of the air in the tyres increases by 15 °C. The volume of the air in the tyre remains the same. Explain in terms of particles why the pressure of the air in the tyre increases when this happens. [1]

21 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (iii) Sometimes the golfer’s hands begin to sweat. Explain in terms of particles how sweating cools his hands. [3]

22 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 10 Fig. 10.1 shows the contents of the human thorax (chest). A … B … Fig. 10.1 (a) On Fig. 10.1, name structures A and B. [2] (b) Oxygen diffuses into the blood from the alveoli inside the lungs. Carbon dioxide diffuses into the alveoli from the blood. (i) Define the term diffusion. [2] (ii) Name the component of blood that transports dissolved carbon dioxide. [1] (iii) When a person is doing vigorous exercise, the concentration of carbon dioxide in the blood increases. Explain why this happens. [2]

23 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (iv) Suggest how this will affect the rate of diffusion of carbon dioxide from the blood to the alveoli. Explain your answer. effect on rate of diffusion explanation [2]

24 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 11 Petroleum (crude oil) is a liquid fossil fuel. (a) Name one solid fossil fuel. [1] (b) Gasoline and diesel are mixtures of liquid hydrocarbons obtained from petroleum. (i) Name the process used to separate gasoline and diesel from petroleum. [1] (ii) State the main use of gasoline and explain, in terms of its chemical properties, why it is suitable for this use. use explanation [2] (c) Natural gas is a gaseous fossil fuel, which contains mainly methane mixed with other compounds such as ethane. (i) Complete the diagram of the structure of one molecule of ethane. C [2] (ii) Complete the word chemical equation for the complete combustion of ethane. ethane + + [2] (d) Ethene, C2H4, is an unsaturated hydrocarbon. Ethene is manufactured by heating large hydrocarbon molecules in the presence of a catalyst. During this process no air must be allowed into the reaction vessel. (i) Name the process used to manufacture ethene. [1]

25 © UCLES 2013 0654/23/O/N/13 [Turn over For Examiner's Use (ii) Suggest one reason why air must be kept out of the reaction vessel. [2]

26 © UCLES 2013 0654/23/O/N/13 For Examiner's Use 12 (a) Fig. 12.1 shows a light ray entering an optical fibre. optical fibre light ray Fig. 12.1 The light ray travels all the way through the optical fibre. Explain why the light ray is able to stay inside the optical fibre. You may draw on the diagram if it helps your answer. [2] (b) White light is passed through a prism as shown in Fig. 12.2. X Y Fig. 12.2 (i) State the colours seen at positions X and Y. X Y [2] (ii) A rainbow is formed in a similar way. Suggest what is acting as a prism when forming a rainbow. [1]

27 © UCLES 2013 0654/23/O/N/13 For Examiner's Use (c) Fig. 12.3 shows a person looking into a mirror and seeing an image. mirror Fig. 12.3 (i) Write the letter X on Fig. 12.3 to show the position of the image of the person’s nose. [2] (ii) Select three words or phrases from the list that describe the image correctly. larger than object real same size as object smaller than object upright upside down virtual [3]

28 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. © UCLES 2013 0654/23/O/N/13 Group 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 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 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 Ra Radium 88 The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.). a X b a = relative atomic mass X = atomic symbol b = proton (atomic) number Key *58-71 Lanthanoid series 90-103 Actinoid series DATA SHEET The Periodic Table of the Elements

CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2013 series 0654 CO-ORDINATED SCIENCES 0654/23 Paper 2 (Core), 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 October/November 2013 series for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level components and some Ordinary Level components.

Page 2 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 23 © Cambridge International Examinations 2013 1 (a) A to cell membrane ; B to nucleus ; C to cell wall/large vacuole ; [3] (b) water ; mineral salts / named mineral ; [2] (c) (i) transport ; of sugars / substances made in the leaves ; [2] (ii) roots have no sucrose / short of nutrients ; no source of energy / cannot respire ; [2] [Total: 9] 2 (a) (i) argon / Ar ; [1] (ii) calcium / lithium and oxygen / sulfur / fluorine ; metal with non-metal ; [2] (b) (i) nucleus ; [1] (ii) 15 ; same as number of electrons / 3 shells = Period 3, 5 outer electrons means Group V so must be phosphorus which has proton number 15 ; [2] (c) (i) magnesium sulphate ; [1] (ii) filter mixture (W) ; dry the solid ; use balance to find mass / weigh it ; [3] [Total: 10] 3 (a) (i) change resistance (of circuit) / change current through resistor ; [1] (ii) X – ammeters need to be in series in a circuit ; [1] (iii) R = V/I ; = 8/0.6 = 13.3Ω ; [2]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 23 © Cambridge International Examinations 2013 (b) decreases decreases stays the same 3 correct = 2 marks, 2 correct = 1 mark ;; [2] (c) length ; diameter / cross sectional area ; [2] [Total: 8] 4 (a) crush / chop ; mix with, ethanol / alcohol ; pour into water ; milky appearance indicates presence of fat ; [max 3] (b) for growth ; for repair ; other use of protein ; [max 2] (c) increases surface area ; idea of making it easier for enzymes to make contact ; [2] (d) proteins not digested ; to amino acids ; proteins cannot be absorbed / amino acids cannot be absorbed ; [max 2] (e) reduction of habitat ; area too small to support populations / reduction in biodiversity / extinction / species become endangered / lack of opportunity to find new medicines ; flooding / leaching of minerals ; due to rain falling directly on soil / lack of protection of tree canopy / increased runoff ; soil erosion ; due to lack of tree roots ; drought ; due to lack of transpiration by trees to form rain leading to desertification ; fewer trees to photosynthesise / less photosynthesis ; to remove carbon dioxide ; burning trees produce CO2 ;

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 23 © Cambridge International Examinations 2013 rotting trees produce CO2 ; by respiration of microbes ; carbon dioxide traps long-wave radiation / infra-red / heat/thermal energy / is a greenhouse gas ; reduces rate of loss of heat from the Earth’s surface ; [max 4] [Total: 13] 5 (a) (i) Q ; orange layer is rust ; formed when iron reacts with (dissolved) air and water ; [3] (ii) calcium / magnesium / zinc ; hydrogen ; [2] (iii) (depends on answer to (ii) must be lower in activity series than (ii) and one which reacts) ideally zinc or iron ; [1] (b) copper electrode and key connected to power supply by wires ; correct polarity copper positive key negative ; electrode and key dipping into the solution ; [3] [Total: 9] 6 (a) three correct linkages uses to type = two marks ;; one correct linkages uses to type = one mark ; three correct linkages type to effect = two marks ;; one correct linkages type to effect = one mark ; [4] screening luggage security marking satellite communication seeing uses X-rays microwave ultra violet visible light type of radiation activates sensitive cells in retina kills cancerous cells heats water in tissues causes tanning of skin effects on tissue

Page 5 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 23 © Cambridge International Examinations 2013 (b) sine wave ; amplitude correctly labelled ; wavelength correctly labelled ; [3] [Total: 7] 7 (a) genotype colour AA normal ; Aa normal aa ; albino [2] (b) phenotype ; [1] (c) (i) (parents’ genotypes) Aa and Aa ; gametes A and a from both parents ; offspring genotypes AA, Aa, Aa and aa ; [3] (ii) 3 : 1 ; [1] (d) breed it with an albino snake ; if any albino offspring it is heterozygous / if no albino offspring it is homozygous ; [2] [Total: 9] 8 (a) (i) carbon dioxide ; [1] (ii) pass gas into limewater; goes cloudy ; [2] (iii) salt ; [1] (iv) 9 ; 3 ; [2]

Page 6 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 23 © Cambridge International Examinations 2013 (b) (i) identifies higher pH with lower acid concentration ; lowering acid concentration decreases the rate ; [2] (ii) temperature ; surface area of calcium carbonate ; degree of agitation of the mixture ; [max 2] [Total: 10] 9 (a) (i) 80m ; [1] (ii) (speed = distance/time = 50/10 =) 5 m / s ; [1] (iii) not moving ; [1] (iv) unbalanced because speed is changing ; [1] (b) geothermal / hydroelectricity / waves / wind / biomass ; [1] (c) (i) kinetic energy ; [1] (ii) (gravitational) potential energy ; [1] (d) density = mass / volume; = 45/36 = 1.25 g / cm3; [2] (e) (i) particles far apart ; irregular arrangement ; [2] (ii) particles move faster therefore more collisions (with tyre wall) ; [1] (iii) heat transferred from body to sweat / heat absorbed by sweat from athlete’s body / heat energy in body reduced by sweating ; kinetic energy of water molecules increase / water molecules move faster ; faster moving / more energetic (water) molecules escape / leave the surface / water molecules turn to gas / vapour ; break bonds / break forces of attraction between molecules ; (KE) / energy of (remaining) water molecules (in sweat) decreases ; [max 3] [Total; 15]

Page 7 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 23 © Cambridge International Examinations 2013 10 (a) A trachea ; B lung ; [2] (b) (i) movement of molecules ; from region of high concentration to low concentration ; down a concentration gradient ; [max 2] (ii) plasma ; [1] (iii) more energy used / more muscle contraction ; reference to respiration / oxidation of glucose ; so more carbon dioxide produced by cells ; so more carbon dioxide diffuses into the blood ; [max 2] (iv) increases ; idea of greater diffusion gradient (from blood to alveolus) ; [2] [Total: 9] 11 (a) coal / peat ; [1] (b) (i) fractional distillation / fractionation ; [1] (ii) (vehicle) fuel ; burns easily / releases much energy when burnt ; [2] (c) (i) 2 C joined by single bond ; 6 H all single bonded to carbon ; [2] (ii) ethane + oxygen → carbon dioxide + water ;; [2] (LHS for 1 mark and RHS for 1 mark) (d) (i) cracking ; [1] (ii) air contains oxygen ; reactant would burn instead of crack / owtte ; [2] [Total: 11]

Page 8 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 23 © Cambridge International Examinations 2013 12 (a) waves are reflected along fibre ; total internal ; [2] (b) (i) correct colours ; correct positions ; [2] (ii) raindrops ; [1] (c) (i) same horizontal level as nose ; same distance behind mirror that nose is from mirror ; [2] (ii) same size as object ; upright ; virtual ; [3] [Total: 10]