Cambridge IGCSE Science - Combined 0653 — 2016 May/June Paper 2 · Variant 1

This document consists of 20 printed pages. DC (LK/SW) 115951/3 © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 0 3 9 6 3 1 1 6 5 2 * COMBINED SCIENCE 0653/21 Paper 2 (Core) May/June 2016 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 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 20. 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 0653/21/M/J/16 © UCLES 2016 1 (a) Complete the sentences below using words or phrases from the list. You may use each word or phrase once, more than once, or not at all. downwards phloem respiration root hairs transpiration upwards upwards and downwards xylem In the plant, water travels upwards in the … . Dissolved sugar travels in the … and moves … . The evaporation of water from the surfaces of the mesophyll cells is called … . [4] (b) Some plant cells were placed on a microscope slide and observed through the microscope. Fig. 1.1 shows one of these cells. nucleus E F starch grains Fig. 1.1 (i) State the names of structures E and F. E … F …[2] (ii) State one piece of evidence from the diagram in Fig. 1.1 that suggests that the plant cell came from under the ground. … …[1] (iii) State the name of the chemical that can be added to the slide to confirm that the plant cell contains starch. … Describe the result of the test. … … [2]

3 0653/21/M/J/16 © UCLES 2016 [Turn over (c) A starch test can also be used to investigate the conditions needed for photosynthesis. • A variegated plant, with green and white areas of leaf, is put in the dark to remove the starch from its leaves. • One leaf of the plant has some black paper put on it as shown in Fig. 1.2 (a), and the plant is left in the light. • A few hours later small discs of leaf, P, Q, R, and S are removed from the leaf and tested for the presence of starch. Fig. 1.2 (b) shows the areas of the leaf that are tested. JUHHQDUHD ZKLWHDUHD EODFNSDSHU )LJ D OHDIDWWKHVWDUW )LJ E DIWHUDIHZKRXUV JUHHQDUHD 5 3 6 4 ZKLWHDUHD EODFNSDSHU Complete Table 1.1 to predict the results of the starch tests. Write an explanation for each prediction. Table 1.1 disc starch present yes (✓) or no (✗) explanation P Q R S [4]

4 0653/21/M/J/16 © UCLES 2016 2 A student investigates the speed of reaction between dilute hydrochloric acid and calcium carbonate. The reaction produces carbon dioxide gas. (a) Fig. 2.1 shows some of the apparatus the student uses. bubbles of gas dilute hydrochloric acid calcium carbonate Fig. 2.1 (i) The student wants to measure the volume of gas produced in this reaction every minute for 10 minutes. Complete Fig. 2.1 to show how the student collects and measures the volume of gas. [2] (ii) Describe the test for carbon dioxide gas. test … result …[2] (iii) As the reaction proceeds, the acid concentration decreases. Describe what happens to the speed of the reaction. …[1]

5 0653/21/M/J/16 © UCLES 2016 [Turn over (b) Complete the word equation for the reaction between hydrochloric acid and calcium carbonate. + calcium chloride + + [2] (c) In a separate reaction, the student adds sodium carbonate to dilute nitric acid. Deduce the name of the salt that is made. …[1]

6 0653/21/M/J/16 © UCLES 2016 3 Fig. 3.1 shows a television camera that moves on rails alongside the athletes on an athletics track. Fig. 3.1 The camera records a 100 metre race from start to finish. At the start the camera begins to move alongside the athletes. They quickly reach their maximum speed and maintain this speed until they cross the finish line. At the end of the race the athletes and the camera quickly stop moving. (a) (i) On the axes in Fig. 3.2, sketch a speed / time graph for the camera from the start until it stops after the end of the race. (Scales and numbers are NOT required.) speed time Fig. 3.2 [2] (ii) On Fig. 3.2, use the letter P to label a point on the graph when the camera is moving at constant speed. [1] (iii) On Fig. 3.2, use the letter R to label a point on the graph when the camera is accelerating. [1]

7 0653/21/M/J/16 © UCLES 2016 [Turn over (b) The winning athlete recorded a time of 9.8 s. Calculate the average speed of this athlete during the 100 m race. Show your working. average speed = … m / s [1] (c) The camera uses a thin converging lens to focus light rays coming from the athlete onto the light sensor inside the camera. (i) Complete the ray diagram in Fig. 3.3 to show how this happens. 15 cm camera light sensor light rays from athlete Fig. 3.3 [1] (ii) The distance from the lens to the light sensor is 15 cm. State the focal length of the lens. …[1] (d) The camera is moved along the rails by an electric motor powered by a battery. Complete the energy transfers that take place while the camera is moving. chemical From … energy stored in the battery to … energy supplied to the motor to … energy of the moving camera. [2]

8 0653/21/M/J/16 © UCLES 2016 4 (a) Fig. 4.1 is a diagram of the internal structure of the heart. septum D C B A Fig. 4.1 (i) State which of the vessels labelled A, B, C and D are arteries. …[1] (ii) On Fig. 4.1 label and name the chamber of the heart that receives blood from the lungs. [2] (iii) State the function of the septum in the heart. … … …[1] (b) Fig. 4.2 shows cross sections of an artery and a vein. The diagrams are not drawn to the same scale. E F Fig. 4.2 State which diagram shows an artery. Explain your answer. diagram … explanation … …[1]

9 0653/21/M/J/16 © UCLES 2016 [Turn over (c) Table 4.1 shows the effect of exercise on an athlete’s heart. The volume of blood pumped by the left ventricle in one minute is called the cardiac output. Table 4.1 activity volume of one heart beat / cm3 pulse rate / beats per minute cardiac output / cm3 per minute resting 65 70 4550 exercising 105 18690 (i) Calculate the pulse rate of the athlete during exercise. Show your working. answer = … beats per minute [2] (ii) The increased cardiac output means that the blood is travelling more quickly around the body. This carries more oxygen to the exercising muscles. Describe other changes in the athlete’s body that enable more oxygen to be taken in at the lungs. … … …[2]

10 0653/21/M/J/16 © UCLES 2016 5 (a) Five substances are to be separated from mixtures. Fig. 5.1 shows the five mixtures and five methods of separation. Draw a straight line from each mixture to the method that is used to obtain the underlined substance from the mixture. One has been done for you. mixture method a red dye from a mixture of dyes chromatography gasoline from petroleum crystallisation solids from river water distillation salt from sea-water filtration water from sea-water fractional distillation Fig. 5.1 [3] (b) An atom of iron has proton number 26 and nucleon number 56. Calculate the number of electrons and the number of neutrons in this atom. number of electrons … number of neutrons … [2]

11 0653/21/M/J/16 © UCLES 2016 [Turn over (c) (i) Predict the type of bonding that occurs when the following pairs of elements react to form compounds. rubidium, a Group I metal + iodine, a Group VII non-metal bonding type … sulfur, a Group VI non-metal + fluorine, a Group VII non-metal bonding type … [2] (ii) During the reaction between rubidium and oxygen the rubidium melts due to a change in the temperature. State the type of chemical reaction that causes this temperature change. …[1] (d) (i) Iron reacts with oxygen. The equation for this reaction is iron + oxygen iron oxide. State whether the iron is oxidised or reduced in this reaction. Explain your answer. iron is … explanation … …[1] (ii) Another substance is involved in the formation of rust. Name this substance. … [1] (iii) Describe one method of rust prevention. Explain how this method prevents rust from forming. method … explanation … … …[2]

12 0653/21/M/J/16 © UCLES 2016 6 Fig. 6.1 shows a thermometer containing a liquid at 20 °C and at 60 °C. 100 80 60 40 20 0 –20 20 °C 60 °C 100 80 60 40 20 0 –20 Fig. 6.1 (a) Complete the sentences below by choosing the correct words from this list: density force mass power volume work When the liquid is heated, the … of the liquid remains the same. The … of the liquid increases on heating, which means that the … of the liquid decreases. [3] (b) Water freezes at 0 °C. Explain why the scale on the thermometer in Fig 6.1 shows that the liquid in the thermometer cannot be water. … … …[1]

13 0653/21/M/J/16 © UCLES 2016 [Turn over (c) Fig. 6.2 shows the bulb of the thermometer placed in hot water at 80 °C. 100 80 60 40 20 0 –20 heat Fig. 6.2 The bulb and stem of the thermometer are made of glass. When the thermometer is placed in the hot water, the top of the stem of the thermometer remains cold to touch, but the liquid level rises to the 80 °C mark. (i) Name the method of thermal energy transfer that takes place in the liquid. …[1] (ii) Suggest why the top of the thermometer stem remains cold to the touch. … …[1]

14 0653/21/M/J/16 © UCLES 2016 (d) Fig. 6.3 shows simple diagrams of the arrangements of molecules in a solid, a liquid and a gas. diagram 1 diagram 2 diagram 3 Fig. 6.3 Complete the statement. Diagram 2 shows a liquid because … … … …[2]

15 0653/21/M/J/16 © UCLES 2016 [Turn over 7 Sometimes humans add untreated sewage to rivers. Fig. 7.1 shows how the concentration of dissolved oxygen and number of bacteria in the river is affected after some sewage is added at point X on the river. W X sewage added here distance moved by water along the river bacteria dissolved oxygen concentration of dissolved oxygen number of bacteria Y Fig. 7.1 After the sewage is added to the water at point X, the water continues to move along the river. (a) Describe and explain how the concentration of dissolved oxygen changes immediately after the sewage is added to the water. … … …[2] (b) The numbers of fish change after the sewage is added to the water. Suggest why there are fewer fish when the water is at point Y, compared with point W. … … …[2] (c) Explain why it is unsafe for humans to drink water containing untreated sewage. … …[1]

16 0653/21/M/J/16 © UCLES 2016 8 (a) Coal is a fuel that is used to heat homes. Fig. 8.1 shows a coal fire. Fig. 8.1 Name the main substance produced during the complete combustion of coal. …[1] (b) Natural gas and petroleum are two other fuels. (i) Coal, natural gas and petroleum are all examples of one type of non-renewable fuel. Name this type of fuel. …[1] (ii) Name the main constituent of natural gas. … [1] (c) Ethene is a hydrocarbon. (i) State the meaning of the term hydrocarbon. … …[2] (ii) Complete the structure of one molecule of ethene. H C [2]

17 0653/21/M/J/16 © UCLES 2016 [Turn over 9 A student investigates the current through a lamp as she varies the potential difference (p.d.) across the lamp. She designs the circuit in Fig. 9.1 to use in her investigation. A Fig. 9.1 (a) (i) Name the component represented by this symbol …[1] (ii) The student has left out an important component from her design. This component is needed to make some of her measurements. On Fig. 9.1 draw the symbol for this missing component in its correct place. [2]

18 0653/21/M/J/16 © UCLES 2016 (b) The student uses the correct circuit to carry out her experiment. Fig. 9.2 shows her results plotted as a graph. 0 0 1 2 3 current / A p.d. / V 4 4 8 12 16 Fig. 9.2 The resistance of the lamp is given by the formula resistance = potential difference (p.d.) current The student says that the resistance of the lamp is higher when the p.d. is 12 V than when the p.d. is 6 V. The resistance at 6 V is 2 Ω. Use the graph in Fig. 9.2 to calculate the resistance at 12 V to show that the student was correct. resistance at 12 V = … Ω [2]

19 0653/21/M/J/16 © UCLES 2016 (c) The current through the metal filament in the lamp is a flow of electric charges. Name the charged particles that carry these charges. …[1] (d) The lamp, when lit, emits radiation in the form of visible light and infra-red radiation. Infra-red radiation has a longer wavelength than visible light. (i) In Fig 9.3 below, write visible light and infra-red in their correct positions in the electromagnetic spectrum. gamma radiation ultraviolet radio waves Fig. 9.3 [2] (ii) State which type of radiation in the electromagnetic spectrum has the highest frequency. …[1]

20 0653/21/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 117 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 Cr 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 6 printed pages. © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education COMBINED SCIENCES 0653/21 Paper 2 Core Theory May/June 2016 MARK SCHEME Maximum Mark: 80 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 0653 21 © Cambridge International Examinations 2016 1 (a) xylem; [4] phloem; upwards and downwards; transpiration; (b) (i) E cytoplasm; [2] F cell wall; (ii) no chloroplasts (present) / no chlorophyll; [1] (iii) iodine solution; [2] starch grains turn blue / black; (c) one mark for each correct row;;;; [4] disc starch present yes(
) or no(X) explanation P
light and chlorophyll are both present Q X no chlorophyll is present R X no light is present S X no light / chlorophyll are present 2 (a) (i) gas syringe / measuring cylinder of water inverted over water; [2] delivery tube with bung from conical flask to gas syringe / measuring cylinder; (ii) limewater; [2] (turns) milky; (iii) decreases / goes more slowly / slower; [1] (b) LHS: hydrochloric acid + calcium carbonate; [2] RHS: carbon dioxide + water; (c) sodium nitrate; [1]

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0653 21 © Cambridge International Examinations 2016 3 (a) (i) graph drawn of the following shape [2] horizontal section (must be straight line, constant speed); steep line (straight or curved) at start (initial acceleration) and final line (straight or curved) to zero (need not be steep); (ii) P placed to label the horizontal section; [1] (iii) R placed to label either sloping sections; [1] (b) average speed (= distance / time) = 100 / 9.8 = 10.2 (m / s); (mark given for 100 / 9.8 or for 10.2) [1] (c) (i) two rays converging to a point on light sensor; [1] (ii) 15 cm (unit required); [1] (d) electrical; [2] kinetic; 4 (a) (i) B and C; [1] (ii) correctly labelled [2] left; atrium; (iii) keeps oxygenated blood separate from deoxygenated blood / stops the blood mixing between the two sides of the heart; [1] (b) diagram E (no mark) [1] has a thick(er) wall; (c) (i) 18 690 / 105; [2] = 178; (ii) breathing more deeply; breathing more quickly; [2]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0653 21 © Cambridge International Examinations 2016 5 (a) [3] 4 correct (3 marks) ;;; 2 or 3 correct (2 marks) 1 correct (1 mark) (b) 26; [2] 30; (c) (i) ionic; [2] covalent; (ii) exothermic; [1] (d) (i) oxidised and (iron) gains oxygen / loses electrons; [1] (ii) water / water vapour / steam; [1] (iii) paint / oil / grease / zinc plate / galvanise; [2] barrier (to oxygen / water); (accept explanation of sacrificial protection)

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0653 21 © Cambridge International Examinations 2016 6 (a) …mass; [3] …volume; …density; (in that order) (b) thermometer scale goes down to –20° / water is not a liquid / will be frozen at this [1] temperature; (c) (i) convection; [1] (ii) glass is a poor / bad conductor; [1] (d) random / not regular arrangement; owtte [Max2] most of the molecules are touching; owtte 7 (a) oxygen level decreased; [Max 2] due to bacteria / micro-organisms; used for respiration; (b) may have died / swum away; [2] due to lack of oxygen / toxins / foul water / disease-causing organisms; (c) idea of [1] may contain pathogenic organisms / toxins / poisons / chemical waste; 8 (a) carbon dioxide; [1] (b) (i) fossil (fuel); [1] (ii) methane; [1] (c) (i) compound / molecule / containing carbon and hydrogen; [2] only; (ii) double bond shown between the two carbon atoms; [2] correct number and positioning of hydrogen atoms;

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0653 21 © Cambridge International Examinations 2016 9 (a) (i) variable resistor / accept variable resistance / rheostat; [1] (ii) [2] correct symbol for voltmeter; voltmeter correctly connected in parallel with lamp; (b) correct reading of current 4A; [2] resistance = 12 / 4 = 3 (Ω); (c) electrons; [1] (d) (i) [2] gamma radiation ultra- violet visible light infrared radio waves visible light in correct box; infrared in correct box; (ii) gamma (waves / radiation); [1]