Cambridge IGCSE Science - Combined 0653 — 2014 Oct/Nov Paper 2 · Variant 3

This document consists of 23 printed pages and 1 blank page. DC (CW/AR) 89393/3 © UCLES 2014 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 3 3 0 9 3 1 1 0 3 7 * COMBINED SCIENCE 0653/23 Paper 2 (Core) October/November 2014 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a 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 24. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question.

2 0653/23/O/N/14 © UCLES 2014 1 A student performs some experiments to find out what makes iron rust. (a) Fig. 1.1 shows his first experiment. 100 80 60 40 water air cotton wool iron filings 20 Fig. 1.1 The student makes sure that the water levels inside and outside the measuring cylinder are in line with the 100 cm3 mark. Fig. 1.2 shows the apparatus after a few days. The iron has rusted and the water has started to rise up the cylinder. 80 60 40 water air cotton wool iron filings 20 100 Fig. 1.2

3 0653/23/O/N/14 © UCLES 2014 [Turn over (i) One of the compounds present in rust is iron oxide. In this compound there are two iron atoms for every three oxygen atoms. State the chemical formula of iron oxide. … [1] (ii) Explain why the water has risen up the cylinder. … …[1] (iii) After a week, the water stops rising although some of the iro n has not rusted. Predict the mark the water finally reaches. … [1] (iv) Name the main element in the gas remaining in the measuring cylinder after one week. …[1] (b) Fig. 1.3 shows the first experiment repeated with the beaker containing oil instead of water. 100 80 60 40 oil air cotton wool iron filings 20 Fig. 1.3 State what happens in this version of the experiment. … Explain your answer. … …[2]

4 0653/23/O/N/14 © UCLES 2014 (c) Describe and explain one method that is used to prevent an iron object from rusting. … … …[2]

5 0653/23/O/N/14 © UCLES 2014 [Turn over 2 (a) Fig. 2.1 shows a man paddling a canoe up a river. The man is paddling gently, but the canoe remains stationary alongside the river bank. R T S U Fig. 2.1 (i) State which force from R, S, T and U is the weight of the canoe and the man, … the force propelling the canoe forward, … the force due to the water current. … [2] (ii) Explain, in terms of balanced forces, why the canoe remains stationary alongside the river bank. … … …[2]

6 0653/23/O/N/14 © UCLES 2014 (b) The man now paddles the canoe steadily so that it moves along the river at a constant speed. On the axes below, sketch a distance / time graph for the canoe as it moves along the river. distance time [1] (c) (i) State the form of stored energy in the man that is transferred from him as he paddles the canoe. …[1] (ii) State the useful form of energy gained by the canoe as a result of this transfer. …[1] (iii) Identify one form of energy that is not useful that is transferred from the man paddling the canoe. …[1] (d) The man now paddles the canoe at a steady speed of 2 m / s. Calculate the time in seconds taken by the canoe to travel 2400 m. State the formula you use and show your working. formula working time = … s [2]

7 0653/23/O/N/14 © UCLES 2014 [Turn over 3 (a) Fig. 3.1 shows one undecayed human tooth and one with decay. tooth A tooth B decay Fig. 3.1 State which type of tooth is shown in both diagrams in Fig. 3.1. … [1] (b) Tooth B shows tooth decay. (i) Suggest why the person had toothache. … …[1] (ii) Explain fully how eating sugary foods can cause tooth decay. … … … … …[3]

8 0653/23/O/N/14 © UCLES 2014 (c) When babies start to eat solid food they do not have enough teeth to chew their food. Explain why it is important that the food should be broken down for them into very small pieces. … … … …[2] (d) In the mouth, the process of chemical digestion starts. Explain what is meant by the term chemical digestion. … … … …[3] (e) Protease (protein-digesting enzyme) digests protein in the acidic environment of the stomach. Predict whether this protease will continue to digest proteins in the alkaline environment of the small intestine. Explain your answer. … … …[2]

9 0653/23/O/N/14 © UCLES 2014 [Turn over 4 Fig. 4.1 shows an electric hairdryer that uses mains electricity. Fig. 4.1 A heater inside the hairdryer warms the air. A fan blows the warm air out of the hairdryer. (a) The hairdryer contains a switch, a heater to warm the air and an electric motor to drive the fan. The heater and the motor are connected in parallel. Fig. 4.2 shows the circuit symbols for a switch, a heater and an electric motor. switch M electric motor electric heater Fig. 4.2 On Fig. 4.3 use the symbols in Fig. 4.2 to complete the circuit diagram for the hairdryer connected to the mains electricity supply. The mains electricity supply has been drawn for you. mains electricity supply Fig. 4.3 [2]

10 0653/23/O/N/14 © UCLES 2014 (b) The flow of warm air dries the wet hair by evaporation. Explain, in terms of molecules, why using warm air helps to dry wet hair. … … …[2] (c) When air is heated, it rises. State the name of the process by which heated air rises. …[1] (d) Fig. 4.4 shows information on a label fixed to the hairdryer. 220 V 5 A Fig. 4.4 (i) State the name of the unit whose symbol is V. …[1] (ii) Use the formula R = V I to find the combined resistance of the circuit components in the hairdryer when in use. Show your working and state the unit of your answer. resistance = … unit = … [2]

11 0653/23/O/N/14 © UCLES 2014 [Turn over (e) The plug on the mains lead of the hairdryer is fitted with a fuse. One day, the fuse blows while the hairdryer is being used. (i) Give one possible cause for the fuse blowing. … …[1] (ii) The fuse has to be replaced. The current through the hairdryer when in use is 5 A. Several new fuses with different current ratings are available, as shown in this list: 2 A 5 A 10 A 15 A Explain which of these four fuses should be used. Fuse … should be used because … … … …[2]

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13 0653/23/O/N/14 © UCLES 2014 [Turn over 5 (a) A student investigates the effect of gravity on the growth of a seedling. The student germinates a seed. When the radicle is clearly visible, he pins the seedling to a board, as shown in Fig. 5.1 (a). He positions the board so that the radical is horizontal. The radicle continues to grow and curves downwards, as shown in Fig. 5.1 (b). radicle pin board board Fig. 5.1 (a) Fig. 5.1 (b) (i) Name the growth response shown by the seedling. … [1] (ii) Explain how this growth response is an advantage to the seedling. … … …[2]

14 0653/23/O/N/14 © UCLES 2014 (iii) In a second experiment the seedling is pinned on the board in a different position, as shown in Fig. 5.2 (a). radicle board board Fig. 5.2 (a) Fig. 5.2 (b) Complete Fig. 5.2 (b) to show the appearance of the radicle after a few days. [1] (b) Fig. 5.3 shows a strawberry plant. The strawberry plant can reproduce both asexually and sexually. plantlet runner Fig. 5.3

15 0653/23/O/N/14 © UCLES 2014 [Turn over The strawberry plant produces runners with plantlets. The runners are stems produced by the parent plant. If the roots of a plantlet come into contact with damp soil, the plantlet can grow into a new independent plant. (i) Use the information provided to explain why reproduction with runners is asexual. … …[1] seeds Fig. 5.4 Fig. 5.4 shows a strawberry produced by the plant after one of the flowers is pollinated. The seeds on the strawberry will produce new plants when they are germinated. (ii) Explain why this method of reproduction is sexual. … …[1] (iii) Describe and explain how a group of plants grown from runners will be different from a group of plants produced when seeds germinate. … … … …[2]

16 0653/23/O/N/14 © UCLES 2014 6 (a) Dilute hydrochloric acid reacts with zinc to produce a colourless gas. Describe a test to show that the gas is hydrogen. test … result … [2] (b) Fig. 6.1 shows the apparatus a student uses to investigate the effect of changing the temperature of acid on the rate of reaction with zinc. dilute hydrochloric acid balance zinc g Fig. 6.1 At the start of the experiment, the student adds the zinc to acid at a temperature of 20 °C. (i) The student expects the balance reading to decrease while zinc reacts with the acid. Suggest the measurements the student makes to find the rate of reaction. … … …[2] (ii) Suggest what he should do to find the effect of temperature on the rate of reaction. … …[1] (iii) Describe the expected effect of temperature on the rate of reaction. … …[1]

17 0653/23/O/N/14 © UCLES 2014 [Turn over (c) The student investigates what happens if he uses copper in place of zinc in the apparatus in Fig. 6.1. (i) Name the part of the Periodic Table in which copper is found. …[1] (ii) Describe and explain what he observes. … … …[2]

18 0653/23/O/N/14 © UCLES 2014 7 Astronomers use telescopes to study the electromagnetic radiation that reaches the Earth from the stars. (a) (i) Complete the sentences below using words from the list. You may use each term once, more than once or not at all. radio waves sound waves ultra-violet visible light water waves People can see stars with their eyes because the stars emit … . Astronomers need special telescopes to see other types of electromagnetic radiation from stars. Examples of such types of radiation are … and … . [2] (ii) We are able to see the Moon, even though the Moon itself does not emit electromagnetic radiation. State a characteristic behaviour of electromagnetic radiation that enables us to see the Moon. …[1] (b) Some stars emit electromagnetic radiation with a very high frequency, such as X-rays. (i) State the meaning of the term frequency. … …[1] (ii) Fig. 7.1 shows an incomplete diagram of the electromagnetic spectrum. gamma radiation microwaves Fig. 7.1 Mark with an X on Fig. 7.1 the part of the spectrum where X-rays are situated. [1] (c) Increasing the amplitude of sound waves makes sound louder. Suggest what effect will be seen when the amplitude of light waves is increased. … …[1]

19 0653/23/O/N/14 © UCLES 2014 [Turn over Question 8 begins on page 20

20 0653/23/O/N/14 © UCLES 2014 8 (a) Diffusion is the net movement of molecules from a region of higher concentration to a region of lower concentration. It is how some substances enter and leave cells. A student carries out an experiment to study diffusion. He uses gelatine cubes of different sizes which represent differently-sized cells. See Fig. 8.1. small gelatine cube large gelatine cube Fig. 8.1 The student immerses the cubes in acid. The gelatine contains a purple indicator that turns colourless when the acid reaches it. See Fig. 8.2. 1 cube purple at start 3 acid has reached the centre 2 acid diffusing into cube Fig. 8.2 The student measures the time taken for the acid to reach the centre of the cubes. The results are shown by the graph in Fig. 8.3. time taken for the acid to reach the centre / min length of side of cube / mm 10 20 30 40 50 5 0 0 10 15 20 Fig. 8.3

21 0653/23/O/N/14 © UCLES 2014 [Turn over (i) Describe how the time taken for the acid to reach the centre varies as the size of the cube increases. … … …[2] (ii) From Fig. 8.3 find the time taken for cubes with a length of 6 mm, … 12 mm. … [2] (iii) In living cells, oxygen and food substances must diffuse across the cell membrane and reach the centre of the cell. Use this information to suggest why cells cannot grow to a large size. … …[1] (b) Fig. 8.4 shows a red blood cell. Fig. 8.4 Describe one feature of the red blood cell that enables oxygen to get to all parts of the cell quickly. … …[1]

22 0653/23/O/N/14 © UCLES 2014 9 (a) Fig. 9.1 shows the apparatus used to demonstrate the electrolysis of copper chloride solution. damp blue litmus paper carbon electrode copper chloride solution + − Fig. 9.1 (i) State the names given to the electrodes. The positive electrode is called the … . The negative electrode is called the … . [2] (ii) A substance X is formed on the negative electrode. Name and describe the appearance of substance X. name of X … description … …[2] (iii) A substance Y is formed at the positive electrode. Name Y and describe its effect on the damp blue litmus paper. name of Y … description … …[2]

23 0653/23/O/N/14 © UCLES 2014 (b) State whether each of the substances involved in the experiment is an element or a compound or a mixture. Write your answers in Table 9.1. Table 9.1 substance element or compound or mixture copper chloride copper chloride solution substance X substance Y water [2] (c) (i) Explain one difference between an element and a compound. … … …[1] (ii) Explain one difference between a compound and a mixture. … … …[1]

24 0653/23/O/N/14 © UCLES 2014 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.). 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. 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.

® IGCSE is the registered trademark of Cambridge International Examinations. CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International General Certificate of Secondary Education MARK SCHEME for the October/November 2014 series 0653 COMBINED SCIENCE 0653/23 Paper 2 (Core Theory), maximum raw mark 80 This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the October/November 2014 series for most Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level components.

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Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0653 23 © Cambridge International Examinations 2014 (c) (i) chemical (energy) ; [1] (ii) kinetic (energy) ; [1] (iii) heat/sound/kinetic energy of the water ; [1] (d) speed = distance/time or (time =) distance/speed ; time = 2400/2 = 1200 (s) ; [2] [Total: 10] 3 (a) premolar/molar ; [1] (b) (i) decay had reached the pulp cavity/nerve ; [1] (ii) bacteria/plaque in the mouth ; feed on sugar ; secrete acids ; acids attack the enamel ; [max 3] (c) small pieces make the food easier to swallow ; increases surface area of food ; speeds up enzyme action/gives better access to enzymes/ ref. to faster/more efficient digestion ; [max 2] (d) breaks down large molecules ; into small (molecules) ; that can be absorbed into the blood/by small intestine ; [3] (e) no (no mark) enzymes are affected by pH ; enzyme will not be at optimum/optimum is acidic pH ; enzyme will be denatured ; [max 2] [Total 12]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0653 23 © Cambridge International Examinations 2014 4 (a) complete circuit ; all components in correct positions (motor and heater either way round) ; [2] (b) heating (the water) gives molecules more energy ; more water molecules have enough energy to escape (from hair) ; (allow any or all points in any equivalent wording, or showing deeper understanding of molecular motion) [2] (c) convection ; [1] (d) (i) volt ; [1] (ii) 220/5 = 44 ; ohm/Ω ; [2] (e) (i) short circuit (accept other reasonable ideas which might lead to fuse melting) ; [1] (ii) 10A (no mark) 2A and 5A fuses would blow ; 15A fuse gives less protection than 10A fuse ; [2] [Total 11]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0653 23 © Cambridge International Examinations 2014 5 (a) (i) geotropism ; [1] (ii) makes sure roots grow downwards/does not matter which way up the seed is planted (the roots will always grow downwards) ; to anchor plant ; to absorb mineral ions/water/nutrients ; [max 2] (iii) radicle curves round 180o ; [1] (b) (i) no sex cells/no gametes involved/only one parent ; [1] (ii) seeds have resulted from fusion of gametes/sex cells/haploid nuclei/ involve two parents ; [1] (iii) plants from runners will be identical and from seeds will show variation ; ref. to genetically ; [2] [Total 8] 6 (a) flame ; explosion/pop ; [2] (b) (i) (measurement of) mass ; (measurement of) time ; [2] (ii) repeat at different temperatures under same conditions ; [1] (iii) increase in temperature causes increase in rate of reaction ; [1] (c) (i) Period 4/transition elements/metals/series ; [1] (ii) no reaction/no change in mass ; copper less reactive than hydrogen/below hydrogen in reactivity series ; [2] [Total 9]

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0653 23 © Cambridge International Examinations 2014 7 (a) (i) visible light ; radio waves and ultra-violet (both required for mark) ; [2] (ii) reflection ; [1] (b) (i) number of vibrations/cycles/oscillations per unit time (accept per second) ; [1] (ii) gamma radiation X ; microwaves [1] (c) brighter ; [1] [Total 6] 8 (a) (i) as the length increased, the time taken (for the acid to reach the centre) increased ; increase is not linear/not proportional ; [2] (ii) 6.5 minutes (allow 0.5 minutes tolerance) ; 20 minutes (allow 0.5 minutes tolerance) ; [2] (iii) time taken for oxygen/food to reach all the parts/middle of the cell would be (too) long ; [1] (b) large surface area/thin/biconcave disc ; [1] [Total 6]

Page 7 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0653 23 © Cambridge International Examinations 2014 9 (a) (i) anode ; cathode ; (in that order) [2] (ii) copper ; pink/brown deposit ; [2] (iii) chlorine ; bleaching of litmus paper ; ignore reference to red or pink colouration [2] (b) compound mixture element element compound 5 or 4 correct for 2 marks, 3 or 2 correct for 1 mark ;; [max 2] (c) (i) an element consists of one type of atom and a compound contains different atoms/elements (bonded together) ; [1] (ii) the composition of a mixture is variable and a compound contains a fixed proportion of elements ; a compound contains atoms/elements bonded together/which are difficult to separate and a mixture is easier to separate ; [max 1] [Total: 10]