Cambridge IGCSE Science - Combined 0653 — 2011 Oct/Nov Paper 2 · Variant 1

This document consists of 20 printed pages. IB11 11_0653_21/3RP © UCLES 2011 [Turn over *7514372702* For Examiner's Use 1 2 3 4 5 6 7 8 9 Total UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/21 Paper 2 (Core) October/November 2011 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 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. www.XtremePapers.com

2 © UCLES 2011 0653/21/O/N/11 For Examiner's Use 1 The chemical reaction involved in the manufacture of ammonia requires an iron catalyst. Fig.1.1 shows a simplified diagram of the reaction vessel in which ammonia is made. nitrogen gas ammonia hydrogen gas catalyst Fig. 1.1 (a) (i) Explain the meaning of the term catalyst. [2] (ii) Iron is a member of the family of metals which lies between scandium and zinc in the Periodic Table. Name this family of metals. [1] (iii) The iron catalyst is prepared by reacting iron oxide with hydrogen gas. The balanced symbolic equation for this reaction is shown below. Fe3O4 + 4H2 3Fe + 4H2O State the total number of atoms shown on the left hand side of this equation. [1] (iv) State the number of hydrogen molecules shown in the equation in (iii). [1]

3 © UCLES 2011 0653/21/O/N/11 [Turn over For Examiner's Use (v) Explain why the reaction in (iii) is an example of a redox reaction. [2] (b) (i) Complete the displayed (graphical) chemical formula of an ammonia molecule, NH3, which has been started below. H — N [2] (ii) A student states that an ammonia molecule contains covalent chemical bonds between its atoms. Explain whether or not the student is correct. [1]

4 © UCLES 2011 0653/21/O/N/11 For Examiner's Use 2 (a) The arrows in Fig. 2.1 show the horizontal forces acting on a car moving forwards. In each case the length of the arrow indicates the size of the force. A B C D Fig. 2.1 (i) State which of the diagrams out of A, B, C and D show a car that is slowing down. [2] (ii) Explain how you decided on your answer to (i). [1] (iii) There are other forces acting on the cars that are not horizontal. Name one of these forces. [1] (b) The car has a radiator. This contains hot water that has been heated by passing it through the hot car engine. The purpose of the radiator is to cool down the water. The radiator is painted black. (i) State the method by which heat is transferred from the hot water to the radiator. [1] (ii) Explain why the radiator is painted black. [1]

5 © UCLES 2011 0653/21/O/N/11 [Turn over For Examiner's Use (c) Fig. 2.2 shows a racing car. Fig. 2.2 The car took 1.5 hours to complete a race of 330 kilometres. Calculate the average speed of the car in kilometres per hour. State the formula that you use and show your working. formula used working km / h [2] (d) Fig. 2.3 shows the speed–time graph for the racing car over a short period of time. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 speed m / s time / s 50 40 30 20 10 0 B A C Fig. 2.3 Describe the motion of the racing car during section B, section C. [2]

6 © UCLES 2011 0653/21/O/N/11 For Examiner's Use 3 Rice and cassava are important parts of a person's diet in some parts of the world. (a) Table 3.1 shows the main nutrients present in 100 g of white rice and 100 g of cassava. Table 3.1 nutrient white rice cassava protein / g 5.0 1.2 carbohydrate / g 58.6 34.7 fat / g 0.4 0.3 (i) Which of the nutrients listed in Table 3.1 can provide energy? [1] (ii) A diet that consists mostly of rice is better for a young child than a diet that consists mostly of cassava. Use the information in Table 3.1 to explain one reason why this is so. [2] (iii) Carbohydrates include sugars and starch. Describe how a student could test a sample of cooked rice to find out if it contains reducing sugar. [3]

7 © UCLES 2011 0653/21/O/N/11 [Turn over For Examiner's Use (b) Fig. 3.1 shows a cassava plant. Fig. 3.1 The cassava plant makes food in its leaves. (i) Describe how food is made by photosynthesis in a plant's leaves. [2] (ii) Suggest and explain one way, visible in Fig. 3.1, in which the structure of a cassava plant's leaves helps them to carry out photosynthesis. [2]

8 © UCLES 2011 0653/21/O/N/11 For Examiner's Use 4 (a) Fig. 4.1 shows an incomplete diagram of the electromagnetic spectrum. radio waves infra-red visible light X–rays Fig. 4.1 (i) Complete the diagram using terms from the list: gamma radiation microwaves ultraviolet [2] (ii) State one use for infra–red radiation, microwaves. [2] (b) Gamma radiation and X-rays are two examples of ionising radiation. (i) Explain the meaning of the term ionising radiation. [2] (ii) Explain why ionising radiation can be harmful to living things. [2]

9 © UCLES 2011 0653/21/O/N/11 [Turn over For Examiner's Use (c) Some types of food are treated with gamma radiation. The radiation kills the microbes that make food decay (i) Explain why gamma radiation can be used for this, even when the fruit is packed in boxes. [1] (ii) Fig. 4.2 shows how a conveyor belt can be used to move the boxes of fresh fruit past the radioactive source. gamma source fresh fruit in fresh fruit out concrete concrete fresh fruit fresh fruit view from above Fig. 4.2 Suggest why concrete is used to surround the radioactive source. [1]

10 © UCLES 2011 0653/21/O/N/11 For Examiner's Use 5 Fig. 5.1 shows a piece of magnesium ribbon which a student has just dropped into a container of dilute sulfuric acid. dilute sulfuric acid magnesium Fig. 5.1 (a) (i) Describe two observations about this reaction which the student could make. 1 2 [2] (ii) Complete the word chemical equation for the reaction in (i). sulfuric acid + + magnesium [2] (iii) State the name of the element which is present in both hydrochloric acid and sulfuric acid. [1]

11 © UCLES 2011 0653/21/O/N/11 [Turn over For Examiner's Use (b) Containers for dilute sulfuric acid are often made of poly(ethene). Poly(ethene) is a polymer which is formed from hydrocarbon monomers. (i) Suggest one property of poly(ethene) which makes it suitable for making sulfuric acid containers. [1] (ii) One method of dealing with waste poly(ethene) is to burn it. Predict two compounds which will be produced when poly(ethene) is burnt. 1 2 [2] (iii) Suggest one advantage of burning as a means of dealing with waste poly(ethene). [1]

12 © UCLES 2011 0653/21/O/N/11 For Examiner's Use 6 Fig. 6.1 shows part of the human nervous system. Fig. 6.1 (a) On Fig. 6.1, use label lines to indicate and name the two parts of the central nervous system. [2] (b) If a person touches a hot pan with his finger, signals pass from his hand, through the central nervous system, to a muscle in his arm. The muscle contracts and moves the arm away. State the correct biological term for each of the following descriptions. (i) the cells in the finger that detect the hot pan and send signals to the central nervous system [1] (ii) an organ such as a muscle that responds to the signals [1]

13 © UCLES 2011 0653/21/O/N/11 [Turn over For Examiner's Use (c) A nerve cell has a nucleus and a cell surface membrane. (i) Name one type of cell in the human body that does not contain a nucleus. [1] (ii) The nucleus contains DNA. State the function of DNA. [1] (iii) Outline one function of the cell surface membrane. [1]

14 © UCLES 2011 0653/21/O/N/11 For Examiner's Use 7 Fig. 7.1 shows some data about the percentage by mass of elements in the Earth’s crust. Al all other elements (18 %) Si (27 %) O (47 %) Fig. 7.1 (a) State the percentage by mass of aluminium in the Earth’s crust. [1] (b) Fig. 7.2 shows a diagram of an ion of element E. nucleus contains 12 protons and 12 neutrons Fig. 7.2 (i) Name element E and explain how the diagram shows that the ion has a positive electrical charge. name of element E [3]

15 © UCLES 2011 0653/21/O/N/11 [Turn over For Examiner's Use (ii) Name the noble gas whose atoms have the same number of electrons as the ion shown in Fig. 7.2 [1] (iii) Explain, in terms of electron configuration, why the atoms of all the noble gases are unreactive. [1] (c) Fig. 7.3 shows a simplified diagram of a process which could be used to produce the reactive metal, sodium. molten sodium chloride electric power supply + – Fig. 7.3 (i) Name the process shown in Fig. 7.3. [1] (ii) Name the element which forms at the anode. [1]

16 © UCLES 2011 0653/21/O/N/11 For Examiner's Use 8 The golden lion tamarin is a species of monkey that lives in forests in Brazil. Its diet includes fruits and nectar from trees. Its predators include snakes, bamboo rats and owls. (a) (i) In the space below, complete the food web, using the information above. trees (fruit and nectar) [3] (ii) On your food web, draw a circle around the producer. [1]

17 © UCLES 2011 0653/21/O/N/11 [Turn over For Examiner's Use (b) The nectar that the monkeys eat is made by flowers that grow on some of the trees in the forests. The fruits that the monkeys eat develop from the flowers. Fig. 8.1 shows a section through a flower. A B Fig. 8.1 (i) Name the parts labelled A and B. A B [2] (ii) On Fig. 8.1, label the part that produces pollen, using a label line and the letter P. [1] (iii) On Fig. 8.1, label the part that will develop into a fruit, using a label line and the letter F. [1] (iv) Explain why the flower produces nectar. [2]

18 © UCLES 2011 0653/21/O/N/11 For Examiner's Use 9 (a) Fig. 9.1 shows the circuit diagram of a circuit which a student set up. He measured the current passing through the 2 Ω resistor. The ammeter reading was 6 A. A X Y 2 Ω Fig. 9.1 (i) Show that the voltage across the resistor was 12 V. State the formula that you use and show your working. formula used working [2] (ii) A 4 Ω resistor is placed in series with the 2 Ω resistor between X and Y. Calculate the total resistance between X and Y. State the formula that you use and show your working. formula used working Ω [2]

19 © UCLES 2011 0653/21/O/N/11 [Turn over For Examiner's Use (b) Many countries are seeking alternatives to fossil fuels as energy sources for generating electricity. Explain why is it necessary to find alternative energy sources for generating electricity. [2]

20 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 2011 0653/21/O/N/11 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 2011 question paper for the guidance of teachers 0653 COMBINED SCIENCE 0653/21 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. • Cambridge will not enter into discussions or correspondence in connection with these mark schemes. Cambridge is publishing the mark schemes for the October/November 2011 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 2011 0653 21 © University of Cambridge International Examinations 2011 1 (a) (i) speeds up reactions ; provides lower activation energy route ; without being chemically altered / owtte ; [max 2] (ii) transition (elements) ; [1] (iii) 15 ; [1] (iv) 4 ; [1] (v) (redox means) oxidation and reduction ; iron oxide is reduced / loses oxygen ; hydrogen is oxidised / gains oxygen ; [max 2] (b) (i) H the only other symbol ; H × 3 shown bonded to central N, all single bonds ; [2] (ii) (correct) non-metallic elements bonded / it is a molecule / electrons are shared ; [1] [Total: 10] 2 (a) (i) C ; D ; [2] (ii) resultant force to right / greater force to right than left ; [1] (iii) gravity / weight / reaction (from ground) ; [1] (b) (i) conduction ; [1] (ii) black surfaces emit, heat / radiation, better ; [1] (c) speed = distance / time ; = 330 / 1.5 = 220 (km / h) ; [2] (d) B constant (speed) ; C decelerating ; [2] [Total: 10]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 21 © University of Cambridge International Examinations 2011 3 (a) (i) all of them / protein, carbohydrate and fat ; [1] (ii) (rice has) more protein ; needed for growth ; [2] (iii) add Benedict's solution / Fehlings solution ; heat ; orange / brick red, colour indicates sugar present ; [3] (b) (i) carbon dioxide combined with water ; using energy from light ; produces, carbohydrate / sugar / starch ; [max 2] (ii) broad / fingered / spreading ; large surface area ; for capturing light / for absorbing carbon dioxide ; [max 2] [Total: 10] 4 (a) (i) microwaves, ultraviolet, gamma ;; (all three correct for two marks, one or two correct for one mark) [2] (ii) thermal imaging cameras / grills / heat lamps ; cooking / communication / mobile phones ; [2] (b) (i) causes atoms to lose electrons ; form ions ; [2] (ii) cancer ; radiation burns ; radiation sickness ; damages DNA / causes mutations ; kills cells ; [max 2] (c) (i) able to penetrate, the food / packaging / have high penetrating power ; [1] (ii) to protect workforce / stop radiation escaping ; [1] [Total: 10]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 21 © University of Cambridge International Examinations 2011 5 (a) (i) gas given off / bubbling ; magnesium, reacts to form soluble products / gets smaller ; gets hotter / exothermic / heat given off ; [max 2] (ii) (magnesium + sulfuric acid) → magnesium sulfate ; + hydrogen ; [2] (iii) hydrogen ; [1] (b) (i) unreactive / not brittle ; [1] (ii) carbon dioxide ; carbon monoxide ; water ; [max 2] (iii) reference to useful heat energy / avoids (expensive) landfill ; [max 1] [Total: 9] 6 (a) label to brain ; label to spinal cord ; [2] (b) (i) receptor / sensory cells ; [1] (ii) effector ; [1] (c) (i) red blood cell ; [1] (ii) controls what the cell does / determines what proteins are made ; [1] (iii) controls what, enters / leaves, the cell ; [1] [Total: 7] 7 (a) 8 (%) ; [1] (b) (i) magnesium ; 12 protons and 10 electrons / (2) more protons than electrons ; protons are positive and electrons are negative ; [3] (ii) neon ; [1] (iii) completed outer shells / no tendency to bond in order to fill shell ; [1] (c) (i) electrolysis ; [1] (ii) chlorine ; [1] [Total: 8]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0653 21 © University of Cambridge International Examinations 2011 8 (a) (i) trees (fruit and nectar) golden lion tamarins bamboo rats snakes owls tamarins correct ; all three predators correct ; all arrows in right direction ; [3] (ii) circle drawn around trees ; [1] (b) (i) A – petal ; B – ovule ; [2] (ii) label P to anther ; [1] (iii) label F to ovary ; [1] (iv) to attract, insects / birds / monkeys ; for pollination ; [2] [Total: 10] 9 (a) (i) voltage = current × resistance ; = 6 × 2 (= 12 V) ; [2] (ii) R = R1 + R2 ; = 6 (Ω) ; [2] (b) finite amount of fossil fuels available / fossil fuels are running out ; burning of fossil fuels produces CO2 ; CO2 contributes to climate change / global warming ; burning fossil fuels produces acid rain / sulfur dioxide ; [max 2] [Total: 6]