Cambridge IGCSE Science - Combined 0653 — 2010 Oct/Nov Paper 2 · Variant 3

This document consists of 21 printed pages and 3 blank pages. IB10 11_0653_23/FP © UCLES 2010 [Turn over *6978631146* For Examiner's Use 1 2 3 4 5 6 7 8 9 10 Total UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/23 Paper 2 (Core) October/November 2010 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, graphs, tables or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. 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. www.XtremePapers.com

2 © UCLES 2010 0653/23/O/N/10 BLANK PAGE

3 © UCLES 2010 0653/23/O/N/10 [Turn over For Examiner's Use 1 (a) Polar bears live in the cold, arctic region. They have thick, white fur. Describe how fur keeps a polar bear warm. [2] (b) (i) Above the arctic region the ozone layer is decreasing, allowing more ultraviolet radiation, which can cause chemical changes, to reach the surface of the Earth. State one danger to human beings of being exposed to large quantities of ultraviolet radiation. [1] (ii) Ultraviolet radiation is part of the electromagnetic spectrum. Name one other radiation which is part of the electromagnetic spectrum and state a use of this radiation. name use [2]

4 © UCLES 2010 0653/23/O/N/10 For Examiner's Use 2 (a) The apparatus shown in Fig. 2.1 can be used to react lead oxide and carbon. strong heat mixture of lead oxide and powdered carbon glass rod drop of limewater Fig. 2.1 When the mixture is heated, molten metal is formed in the container and the drop of lime water on the end of the glass rod becomes cloudy. (i) Suggest the word equation for the reaction between lead oxide and carbon. Do not write a symbolic equation. [2] (ii) State one substance, shown in your equation in (i), which is a compound. Explain why this substance is described as a compound and not as an element. substance explanation [3]

5 © UCLES 2010 0653/23/O/N/10 [Turn over For Examiner's Use (b) Fig. 2.2 shows some of the apparatus used in the electrolysis of copper chloride solution. copper chloride solution Z test-tube electrolysis cell X Y Fig. 2.2 (i) What is missing from position Z in Fig. 2.2? [1] (ii) Name the gas which collects in the test-tube, and explain whether electrode X is the anode or the cathode. gas Electrode X is the because [2]

6 © UCLES 2010 0653/23/O/N/10 For Examiner's Use 3 A healthy plant growing in a pot was watered and placed in a sunny window. A transparent plastic bag was placed over the plant, as shown in Fig. 3.1. soil pot transparent plastic bag Fig. 3.1 (a) The temperature near the window fell overnight. The next morning, small droplets of liquid water were visible on the inside of the plastic bag. (i) Name the process by which plant leaves lose water vapour. [1] (ii) Name the small holes in the leaf through which the water vapour is lost. [1] (iii) Explain why the water formed droplets of liquid on the plastic bag. [2]

7 © UCLES 2010 0653/23/O/N/10 [Turn over For Examiner's Use (b) Fig. 3.2 shows a cell from the plant leaf. Fig. 3.2 (i) On the diagram of the cell in Fig. 3.2, label and name two structures that would not be present in an animal cell. [2] (ii) Name the part of the leaf in which this cell could be found. [1] (iii) The cell in Fig. 3.2 can photosynthesise. Write the word equation for photosynthesis. + + [2]

8 © UCLES 2010 0653/23/O/N/10 For Examiner's Use 4 (a) Fig. 4.1 shows the speed-time graph for a train. 7 6 5 4 3 2 1 0 A B C D 0 20 40 60 time / s 80 100 120 speed m / s A B C D Fig. 4.1 The brakes are applied at C. Calculate how long it takes the train to stop. s [1] (b) Another train, on a journey lasting 10 minutes, travelled at a constant speed of 9 m / s. (i) Show that the distance travelled by the train during this journey was 5400 m. State the formula that you use and show your working. formula used working [2]

9 © UCLES 2010 0653/23/O/N/10 [Turn over For Examiner's Use (ii) The average force needed for the train to maintain the speed of 9 m / s was 10 000 N. Calculate the work done by the train over 10 minutes. State the formula that you use and show your working. formula used working J [2]

10 © UCLES 2010 0653/23/O/N/10 For Examiner's Use 5 Fig. 5.1 shows some stages in the formation of a human fetus. ball of cells fetus zygote egg cell sperm cell amnion amniotic fluid Fig. 5.1 (a) Most human cells contain 46 chromosomes, but egg cells and sperm cells contain only 23 chromosomes each. Suggest a reason for this. [1] (b) Name the part of the reproductive system in which each of these events takes place. (i) Eggs are produced. [1] (ii) Fertilisation. [1] (c) Describe the function of the amnion. [2]

11 © UCLES 2010 0653/23/O/N/10 [Turn over For Examiner's Use (d) The fetus develops in the uterus. It is attached to the uterus by the umbilical cord and placenta. It obtains nutrients from its mother's blood, through the placenta. Suggest why a pregnant woman should have more iron and calcium in her diet than when she is not pregnant. iron calcium [3]

12 © UCLES 2010 0653/23/O/N/10 For Examiner's Use 6 (a) Electrical equipment can be dangerous, especially when it is handled with wet hands. Explain why you are quite likely to be electrocuted if you handle an electrical device with wet hands rather than dry hands. [1] (b) Fig. 6.1 shows a simple electric circuit. lamp cell ammeter voltmeter Fig. 6.1 Draw the circuit diagram for the circuit in Fig. 6.1 using the correct symbols. [3]

13 © UCLES 2010 0653/23/O/N/10 [Turn over For Examiner's Use (c) Fig. 6.2 shows a circuit built by a student. J K L A B two-way switch Fig. 6.2 (i) The switch is at position B. Which lamps will be lit? [1] (ii) The switch is then moved to position A. What happens to lamps J, K and L? lamp J lamp K lamp L [2] (d) The student has six resistors as shown in Fig.6.3. 4 Ω 8 Ω 12 Ω 4 Ω 8 Ω 12 Ω Fig.6.3 Describe how he can combine two of these resistors to get a total resistance of 20 ohms. [1]

14 © UCLES 2010 0653/23/O/N/10 For Examiner's Use (e) Power stations produce electricity. Six stages in the production of electricity at a coal-fired power station are shown below. A electricity produced B coal burned C steam produced D turbine driven by steam E turbine turns generator F water boils Using the letters A to F, list the stages in the correct order in the boxes below. Two have been done for you. C A [2]

15 © UCLES 2010 0653/23/O/N/10 [Turn over BLANK PAGE Please turn over for Question 7.

16 © UCLES 2010 0653/23/O/N/10 For Examiner's Use 7 (a) The chemical symbols for the atoms shown below include proton (atomic) numbers and nucleon (mass) numbers. O 16 8 P 31 15 S 32 16 Ga 70 31 (i) State which of these symbols represent atoms of elements in the same group of the Periodic Table [1] (ii) Complete Table 7.1 which shows the names and the numbers of protons and neutrons in two of the atoms shown above. Table 7.1 element name protons neutrons oxygen 15 16 [2] (b) Chlorine and hydrogen combine to form hydrogen chloride which dissolves in water to produce hydrochloric acid. (i) Suggest a substance which reacts with hydrochloric acid to form the salt, copper chloride. [1] (ii) Suggest an element from the third period of the Periodic Table which reacts safely with hydrochloric acid to produce hydrogen gas. [1]

17 © UCLES 2010 0653/23/O/N/10 [Turn over For Examiner's Use (c) Ethene is a gaseous compound of carbon and hydrogen. Fig. 7.2 shows two different chemical reactions, 1 and 2, involving ethene. ethene reaction 1 reaction 2 carbon dioxide + water poly(ethene), a type of polymer Fig.7.2 (i) For reactions 1 and 2, deduce the type of chemical reaction which occurs. reaction 1 reaction 2 [2] (ii) For reaction 2, describe briefly what happens to the molecules of ethene during the reaction. [1]

18 © UCLES 2010 0653/23/O/N/10 For Examiner's Use 8 Soya beans are an important crop in many tropical and subtropical countries, because they contain a lot of protein. (a) Fig. 8.1 shows how the yield of soya beans is affected by the pH of the soil in which they are grown. 4.0 4.5 5.0 5.5 6.0 pH 6.5 7.0 7.5 8.0 2500 2000 1500 1000 500 0 yield / kg per hectare Fig. 8.1 A farmer grows soya beans in a field where the soil has a pH of 5.5. (i) What yield of beans could he get from his crop? kg per hectare [1] (ii) State the pH range in which soya beans grow best. between and [1] (iii) The farmer decides to add calcium carbonate to the soil in his field. Explain why this would help him to achieve a higher yield of soya beans. [2]

19 © UCLES 2010 0653/23/O/N/10 [Turn over For Examiner's Use (b) The field is on a steep slope. Describe two things the farmer could do to reduce the risk of soil erosion. 1 2 [2] (c) Soya beans are seeds. They grow after the flowers on the soya plants have been pollinated. (i) Soya flowers often have violet-coloured petals. Suggest how soya flowers are pollinated. [1] (ii) Explain why soya beans only grow after the flowers have been pollinated. [2] (iii) Describe how you would test a soya bean seed for protein. State the result you would expect. test result [2]

20 © UCLES 2010 0653/23/O/N/10 For Examiner's Use 9 (a) Complete Table 9.1 to show the properties of alpha, beta and gamma radiations. Table 9.1 description charge range in air ionising ability alpha positive 5 cm very strong beta electron 50 cm gamma wave many kilometres weak [4] (b) Many people have smoke detectors in their houses. Smoke detectors contain a radioactive source which emits alpha radiation. Explain why the alpha radiation from the smoke detector is not dangerous to people living in the house. [1]

21 © UCLES 2010 0653/23/O/N/10 [Turn over For Examiner's Use 10 In many countries, river water is collected and treated to make it safe for humans to drink. (a) State and explain which two of the processes shown below are used to treat river water so that it becomes safe to drink. adding chlorine chromatography evaporation filtration first process explanation second process explanation [4] (b) Sulfur dioxide is a gaseous compound which is released into the air when fossil fuels containing sulfur compounds are burned. (i) Describe how sulfur dioxide gas could cause pollution of water in rivers and lakes. [3] (ii) Suggest one way in which sulfur dioxide emissions into the atmosphere are being reduced. [1]

22 © UCLES 2010 0653/23/O/N/10 For Examiner's Use (c) Fig. 10.1 shows a diagram of a water molecule, H2O. Choose words or phrases from the following list to complete the labelling of the diagram. covalent bond hydrogen atom ionic bond nucleus oxygen atom proton … … … Fig. 10.1 [3]

23 © UCLES 2010 0653/23/O/N/10 BLANK PAGE

24 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 2010 0653/23/O/N/10 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

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2010 question paper for the guidance of teachers 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 must be read in conjunction with the question papers and the report on the examination. • CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses. www.XtremePapers.com

Page 2 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2010 0653 23 © UCLES 2010 1 (a) 1. traps (layer of) air ; 2. acts as insulator / reduces conduction / reduces convection ; [2] (b) (i) increased risk of skin cancer / eye damage / sun burn ; [1] (ii) 1. wave ; 2. use ; [2] [Total: 5] 2 (a) (i) lead oxide + carbon → lead + carbon dioxide LHS ; RHS ; [2] (ii) 1. lead oxide / carbon dioxide ; ecf 2. compounds contain more than one type of element / atom ; 3. reference to (different) elements / atoms in compounds being joined / bonded ; [3] (b) (i) (dc) power supply / battery / cell ; [1] (ii) 1. chlorine ; 2. anode, non-metals form at the anode / chlorine is a non-metal / chloride ions are negative (and anode is positive) ; [2] [Total: 8] 3 (a) (i) transpiration / evapotranspiration / diffusion ; [1] (ii) stomata ; [1] (iii) 1. condensation ; 2. water vapour cooled / temperature fell ; 3. gas changed to, liquid / water ; 4. ref. to particles and (kinetic) energy ; [max 2]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2010 0653 23 © UCLES 2010 cell wall vacuole chloroplast (b) (i) cell sap / [max 2] (ii) palisade (mesophyll) ; 1 (iii) 1. carbon dioxide + water ; 2. glucose / carbohydrate / starch / sugar + oxygen ; [2] [Total: 9] 4 (a) 28 (s) ; [1] (b) (i) 1. distance = speed × time ; 2. = 10 × 60 × 9 = 5400 m ; [2] (ii) 1. work done = force × distance ; 2. = 10 000 × 5400 = 54 000 000 J ; [2] [Total: 5] 5 (a) idea of restoring full number of chromosomes in the zygote ; [1] (b) (i) ovary ; [1] (ii) oviduct / Fallopian tube ; [1] (c) 1. produces / contains, (amniotic) fluid ; 2. protects / supports, embryo ; [2] (d) 1. idea that mother’s body needs to make substances for both herself and the fetus ; 2. iron for haemoglobin ; 3. calcium for, bones / teeth ; [3] [Total: 8]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2010 0653 23 © UCLES 2010 6 (a) water conducts electricity ; [1] (b) all symbols in correct circuit ;;; all four correct for 3 marks any three correct for 2 marks all two correct for 1 mark [3] (c) (i) K and L ; [1] (ii) 1. J lights up ; 2. K & L go off ; [2] (d) add one 12 Ω to one 8 Ω (in series) ; [1] (e) B F C D E A B F ; D E ; [2] [Total: 10] 7 (a) (i) O and S ; [1] (ii) element name protons neutrons (oxygen) 8 8 phosphorus (15) (16) one mark for each row ;; [2] (b) (i) copper oxide / copper carbonate / other correct ; [1] (ii) magnesium ; [1] (allow aluminium) (c) (i) reaction 1 combustion / oxidation ; reaction 2 polymerisation ; [2] (ii) (molecules) join together / form chains ; [1] [Total: 8]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2010 0653 23 © UCLES 2010 8 (a) (i) 2000 (kg per hectare) ; [1] (ii) any two values with a range between 6 and 7.25 ; [1] (iii) 1. calcium carbonate is a base ; 2. neutralise (acid in the soil) ; 3. raise pH ; 4. above 5.5 / closer to 6.0 ; [2 max] (b) 1. terracing / walls (qualified) ; 2. bunds / embankment / ditch ; 3. plough along slope (not up and down) ; 4. keep crop cover (at all times) / plant trees ; 5. other valid points ; ; [2 max] (c) (i) insects ; allow self-pollination [1] (ii) 1. pollen contains male gamete ; 2. fertilisation must take place ; 3. male gamete (in pollen grain) fuses with female gamete ; 4. seed develops from (fertilised) ovule ; [2 max] (iii) 1. biuret test / add biuret reagent / add copper sulfate and KOH solution ; 2. purple / lilac / mauve ; [2] [Total: 11] 9 (a) description charge range in air ionising ability alpha helium nucleus positive 5 cm very strong beta electron negative 50 cm medium gamma wave none many kilometres weak ;;;; [4] (b) alpha particles have low penetration in air / will not reach people living in house / smoke detectors are a long way from people ; [1] [Total: 5]

Page 6 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2010 0653 23 © UCLES 2010 10 (a) 1. adding chlorine ; 2. kills (harmful) bacteria / microorganisms / germs ; 3. filtration ; 4. removes solid / insoluble materials / dirt ; 4 (b) (i) 1. dissolves in / reacts with rain water ; 2. produces acidic solution / acid rain ; 3. ref. to sulfurous / sulfuric acid ; 4. acidic rain collects in rivers / lakes ; 5. reference to harmful effects of acidity, e.g. kills organisms ; max 3 (ii) removal of sulfur compounds from fuel / removal of sulfur dioxide from waste gases / reduce demand for energy / burn less fuel ; max 1 (c) … covalent bond … hydrogen atom … oxygen atom 3 [Total: 11]