Cambridge IGCSE Science - Combined 0653 — 2004 May/June Paper 3 · Variant 1

This document consists of 20 printed pages. SP (KN) S63769/3 © UCLES 2004 [Turn over UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/03 Paper 3 May/June 2004 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 in the spaces provided on the Question Paper. 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. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. A copy of the Periodic Table is printed on page 20. Centre Number Candidate Number Name If you have been given a label, look at the details. If any details are incorrect or missing, please fill in your correct details in the space given at the top of this page. Stick your personal label here, if provided. For Examiner’s Use 1 2 3 4 5 6 7 8 9 Total www.XtremePapers.com

2 0653/03/M/J/04 1 Gasoline is a liquid hydrocarbon fuel. Fig. 1.1 shows a gasoline fire. Fig. 1.1 (a) (i) State the meaning of the term hydrocarbon. … …[2] (ii) In a plentiful supply of air many hydrocarbons burn with an almost invisible flame. Suggest why the fire in Fig. 1.1 produced clouds of black smoke. … … …[2] (iii) A fire-fighter sprays foam containing carbon dioxide over the fire in order to put it out. Explain why the fire goes out. … … …[2] foam containing carbon dioxide For Examiner’s Use © UCLES 2004

3 0653/03/M/J/04 [Turn over (b) The balanced equation in Fig. 1.2 shows the complete combustion of ethene. The substances involved are shown as displayed (graphical) formulae. Fig. 1.2 (i) Rewrite the equation as a normal balanced equation using molecular formulae. …[2] (ii) Explain why this equation is said to be balanced. … …[1] (iii) On Fig. 1.2 indicate with the letter B and a labelling line one of the chemical bonds which is broken in the reaction. [1] (iv) On Fig. 1.2 indicate with the letter M and a labelling line one of the chemical bonds which is formed in the reaction. [1] H C H H C O O O O O C O O C O H O H H O H O O + + H For Examiner’s Use © UCLES 2004

4 0653/03/M/J/04 2 A student measured the pH of the water in two lakes, lake X and lake Y. The water in lake X had a pH of 5.4, while the water in lake Y had a pH of 6.8. The student made a survey of the animals living in each lake. He took the same number and size of water samples from each lake, and identified every species of animal which he found. He then counted how many individual animals he found that belonged to each species. Table 2.1 summarises his results. Table 2.1 (a) Which lake had the higher species diversity? Explain your answer. … …[1] For Examiner’s Use © UCLES 2004 species number of number of individuals in individuals in lake X lake Y A 58 12 B 0 6 C 93 15 D 0 2 E 6 22 F 1 0 G 0 3 H 0 1 I 61 6 J 0 2

5 0653/03/M/J/04 [Turn over (b) Both lakes were in areas where acid rain of pH3 regularly fell. However, lake Y was in an area where the rocks were mostly limestone. (i) What evidence did the student find which suggests that the acid rain had less effect on the water in lake Y than in lake X? … …[1] (ii) Suggest why the acid rain had less effect on the water in lake Y than in lake X. … …[1] (c) Explain why removing sulphur from fossil fuels can help to reduce the problems caused by acid rain. … … …[2] (d) Soil erosion is another problem which can harm communities of organisms living in lakes. Soil washed off the land into a lake can form a suspension in the water, preventing light from passing through. Explain how this would disrupt the food web in the lake. … … … …[3] For Examiner’s Use © UCLES 2004

6 0653/03/M/J/04 3 Fig. 3.1 shows a weightlifter. Fig. 3.1 (a) The total weight lifted by the weightlifter is 1600 newtons, which he lifts through 2 metres in 0.5 seconds. (i) Calculate the work done on the bar and weights. Show your working and state the formula that you use. formula working …[2] bar weights For Examiner’s Use © UCLES 2004

7 0653/03/M/J/04 [Turn over (ii) Calculate the power developed by the weightlifter while lifting the bar and weights. Show your working and state the formula that you use. formula working …[2] (b) (i) What form of energy has been gained by the bar and weights as a result of lifting them? …[1] (ii) The weightlifter suddenly drops the bar and weights, and the energy gained in (i) is now transferred to another form. Name this form of energy. …[1] For Examiner’s Use © UCLES 2004

8 0653/03/M/J/04 4 The element chlorine is an important substance used in the manufacture of many products, including bleaches and sterilising agents. (a) Explain why experiments involving chlorine must always be carried out in a fume cupboard. … …[1] (b) Two bleaches, STAINAWAY and SUPERWHITE contain chlorine that is easily released from solution. They are tested in a laboratory to find out which contains the greater amount of chlorine. A chemist carries out the test shown in Fig. 4.1. She adds 1.0 cm3 of bleach to 10.0 cm3 of excess sodium iodide solution. Fig. 4.1 The observations made by the chemist are shown in Table 4.1. In both tests, the mixture changes colour from colourless to brown because iodine is formed. Table 4.1 1.0 cm3 SUPERWHITE 1.0 cm3 STAINAWAY 10.0 cm3 of sodium iodide solution For Examiner’s Use © UCLES 2004 bleach colour of mixture STAINAWAY dark brown SUPERWHITE light brown

9 0653/03/M/J/04 [Turn over (i) Explain briefly why iodine is formed in these reactions. … …[1] (ii) Explain how the observations allow the chemist to decide which bleach contains the greater amount of chlorine. … … … …[2] (c) (i) Draw a diagram of a chlorine molecule, showing how all of the outer shell electrons are arranged. [2] (ii) Name the type of chemical bond you have drawn in (i). …[1] For Examiner’s Use © UCLES 2004

10 0653/03/M/J/04 5 A farmer grows fruit that he sells to a supermarket. The supermarket wants the fruit to contain high concentrations of vitamin C. The supermarket buyer has a simple test kit which she uses to test the vitamin C content of the fruit. She tells the farmer that fruit from trees with the genotype AA or Aa is high in vitamin C. Fruit from trees with the genotype aa is low in vitamin C. The farmer decides to breed from some of his trees, to produce a large number of trees which all produce fruit high in vitamin C. (a) (i) State the genotype of the trees which the farmer should use for breeding, in order to be sure that all of the offspring have fruit which is high in vitamin C. …[1] (ii) Using genetic diagrams, explain how he can carry out a test cross to find out whether the genotype of a tree is AA or Aa. [4] For Examiner’s Use © UCLES 2004

11 0653/03/M/J/04 [Turn over (b) The buyer from the supermarket suggests that it would be better if the farmer propagated the trees asexually, rather than sexually. Is she correct? Explain your answer. … … … …[2] (c) Explain why it is good for people to eat fruit that is high in vitamin C. … … …[2] For Examiner’s Use © UCLES 2004

12 0653/03/M/J/04 6 (a) There are three states of matter – solid, liquid and gas. Fig. 6.1 shows the arrangement of particles in a liquid. Fig. 6.1 Draw similar diagrams for a solid and a gas. [2] (b) A long bridge is made in sections, with gaps between each section. The gaps are filled with rubber. (i) Suggest why these gaps are left. … … …[2] road road rubber solid gas For Examiner’s Use © UCLES 2004

13 0653/03/M/J/04 [Turn over (ii) The gaps are left every 50 m. A car travels over the bridge at 20 m / s. Calculate how long the car will take to travel from one gap to the next. Show your working and state the formula that you use. formula working …[2] (c) Answer the following in terms of conduction, convection and radiation. (i) Cooking pans often have handles made of plastic or wood. Why do these help to prevent you burning your hand when using the pan? … …[1] (ii) On a sunny day your body gets hotter when wearing a black shirt than when wearing a white shirt. Explain why this happens. … … … …[2] For Examiner’s Use © UCLES 2004

14 0653/03/M/J/04 (iii) In a refrigerator, the freezer compartment is usually placed at the top. Why does this help the working of the refrigerator? … …[2] freezer compartment For Examiner’s Use © UCLES 2004

15 0653/03/M/J/04 [Turn over 7 The air is a mixture of many substances. (a) Complete Table 7.1 which shows information about substances in unpolluted air. Table 7.1 [3] (b) Fig. 7.1 shows apparatus which can be used to measure the percentage of oxygen in 100 cm3 of air. Fig. 7.1 When the plunger of gas syringe A is pushed into the syringe, the air flows through the tube containing the heated copper and fills gas syringe B. During the experiment oxygen reacts with the hot copper forming copper(II) oxide. (i) Describe how the apparatus is used to measure the percentage of oxygen in air. … … … … … …[3] 100 100 50 50 air plunger copper heat gas syringe A gas syringe B For Examiner’s Use © UCLES 2004 substance chemical formula of approximate % in air molecules nitrogen oxygen

16 0653/03/M/J/04 (ii) During the reaction oxygen atoms are reduced to oxide ions. In the boxes below draw an oxygen atom and an oxide ion, showing all of the electrons in each particle. [2] (iii) State the electrical charge of the oxide ion you have drawn in (ii). …[1] (iv) State, in terms of electrons, why the change of an oxygen atom into an oxide ion is called reduction. … …[1] For Examiner’s Use © UCLES 2004 oxygen atom oxide ion

17 0653/03/M/J/04 [Turn over 8 (a) Fig. 8.1 shows some red blood cells in a concentrated glucose (sugar) solution. Fig. 8.1 Using your knowledge of osmosis, explain what will happen to the red blood cells. … … …[2] (b) In the body, red blood cells are surrounded by blood plasma. The glucose concentration in the plasma is kept constant. (i) Explain how the blood glucose concentration is brought down to normal if it rises too high. … … … …[3] (ii) State the term which is used to describe the maintenance of constant internal conditions in the body. …[1] red blood cell cytoplasm - a less concentrated solution cell surface membrane concentrated solution For Examiner’s Use © UCLES 2004

18 0653/03/M/J/04 (c) Blood glucose concentration usually rises a few hours after we eat food containing starch. Explain how this happens. … … … …[3] For Examiner’s Use © UCLES 2004

19 0653/03/M/J/04 9 (a) Fig. 9.1 shows a circuit containing three identical resistors. Fig. 9.1 A voltmeter connected across AB reads 6 V. State the voltmeter reading when connected across CD … , FG … . [2] (b) Draw a circuit diagram, using correct symbols, for a circuit with a cell, a switch, a lamp, a motor and a variable resistor that controls the speed of the motor but does not affect the brightness of the lamp. [3] (c) A student is given 3 resistors 2 Ω, 2 Ωand 4 Ω. Explain how he could connect 2 or 3 of these resistors to produce a combined resistance of (i) 6 Ω, … [2] (ii) 1 Ω. … [2] A C D B F G E For Examiner’s Use © UCLES 2004

20 0653/03/M/J/04 © UCLES 2004 Group DATA SHEET 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 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 Sulphur 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