Cambridge IGCSE Science - Combined 0653 — 2012 May/June Paper 2 · Variant 2

This document consists of 18 printed pages and 2 blank pages. IB12 06_0653_22/5RP © UCLES 2012 [Turn over *4522543892* 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 0653/22 Paper 2 (Core) May/June 2012 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 2012 0653/22/M/J/12 For Examiner's Use 1 (a) Most atoms of metallic elements found in the Earth’s crust exist in compounds called ores which are contained in rocks. The chemical formulae of some metal compounds found in ores, together with the names of the ores, are shown below. argentite Ag2S chromite FeCr2O4 galena PbS scheelite CaWO4 (i) A binary compound is one that contains only two different elements. State which of the compounds in the list above are binary compounds. [1] (ii) State the ore from which the metallic element tungsten could be extracted. [1] (b) Fig. 1.1 shows a diagram of an atom of the element lithium. This atom has a nucleon number (mass number) of seven. + + + – – – … … Fig. 1.1 Complete Fig. 1.1 by labelling the particles that exist in the nucleus. [2]

3 © UCLES 2012 0653/22/M/J/12 [Turn over For Examiner's Use (c) (i) A teacher dropped a small piece of sodium into a beaker containing cold water and a thermometer. She stirred the mixture until all of the sodium had reacted. thermometer sodium Predict two observations that could be made as the sodium reacts with the water. 1 2 [2] (ii) Potassium is another element in the same group of the Periodic Table as sodium. State one way in which the reaction of potassium with cold water would be different from that of sodium. [1] (iii) Complete the word chemical equation for the reaction between potassium and water. potassium water + + [2]

4 © UCLES 2012 0653/22/M/J/12 For Examiner's Use 2 An athlete warms up by running along a race track. (a) He accelerates from rest and after 10 seconds reaches a maximum speed of 7 m / s. He continues at this speed for another 10 seconds. During the next 5 seconds, he steadily slows down and stops. Draw a speed-time graph to show the motion of the athlete. [4] (b) During a race the athlete cools down by sweating. (i) Explain how evaporation cools down the athlete. [2] (ii) State two factors which would increase the rate of evaporation. and [2]

5 © UCLES 2012 0653/22/M/J/12 [Turn over For Examiner's Use 3 (a) Define the term respiration. [2] (b) Table 3.1 shows the percentages of three gases in inspired air and in expired air. Write the name of each gas in Table 3.1. Table 3.1 gas percentage in inspired air percentage in expired air 21 17 0.04 4 78 78 [3] (c) Outline how oxygen is transported to a respiring cell in a muscle. [2] (d) When adrenaline is secreted, oxygen is transported more quickly to the muscles. (i) How does adrenaline have this effect? [1] (ii) State one situation in which adrenaline secretion increases. [1] (iii) Name the body organ that destroys adrenaline after it has been secreted. [1]

6 © UCLES 2012 0653/22/M/J/12 For Examiner's Use 4 (a) Radio waves are electromagnetic waves. Sound waves are not. State one other way in which radio waves differ from sound waves. [1] (b) Fig. 4.1 shows two lists. The first is a list of different types of electromagnetic wave. The second is a list of some of their uses. Draw lines to connect each type of radiation to its use. [3] radiation gamma microwave infra-red X-rays use examining bones and teeth remote controls for television sets satellite communications sterilising surgical instruments Fig. 4.1 (c) A student carried out an experiment to find the speed of sound in air by watching and listening to a bell being rung. He stood 500 m from the bell. bell tower student 500 m

7 © UCLES 2012 0653/22/M/J/12 [Turn over For Examiner's Use The sound took 1.5 s to travel from the bell to the student. (i) Calculate the speed of sound. State the formula that you use and show your working. formula used working m / s [2] (ii) The sound wave produced by the bell had a frequency of 400 Hz. State the approximate frequency range which humans can hear. Hz to Hz [1] (iii) The mass of the bell is 10 000 kg and it has a volume of 1.1 m3. Calculate the density of the bell. State the formula that you use and show your working. formula used working kg / m3 [2]

8 © UCLES 2012 0653/22/M/J/12 For Examiner's Use 5 Water supplies are often impure and have to be purified to make them safe for humans to drink. (a) State one process that is used to make water safe for humans to drink. Explain, for the process you have chosen, how this process purifies the water. process how it purifies [2] (b) Water is a compound which contains the elements hydrogen and oxygen. Describe one difference, other than physical state, between the compound water and a mixture of the elements hydrogen and oxygen. [2] (c) Table 5.1 shows information about water and two compounds that can form mixtures with water. Table 5.1 compound melting point / °C boiling point / °C solubility in water water 0 100 – sodium chloride 801 1413 soluble hexane –95 69 insoluble (i) Describe briefly how a sample of sodium chloride could be obtained from a solution of sodium chloride. [2]

9 © UCLES 2012 0653/22/M/J/12 [Turn over For Examiner's Use (ii) Use the information in Table 5.1 to predict and explain whether or not a mixture of hexane and water could be separated at room temperature (20 °C) by the method of filtration. [2] (d) A student burned a small piece of magnesium, using the apparatus shown in Fig. 5.1. air magnesium burning gas jar water Fig. 5.1 When the reaction finished, the magnesium oxide was mixed with the water in the bottom of the gas jar. (i) Magnesium oxide is made of positive ions and negative ions. Describe briefly what happens to an atom when it is converted into a negative ion. [1] (ii) The student added a few drops of full range indicator solution (Universal Indicator) to the mixture of water and magnesium oxide. The indicator changed from green to blue. Explain why this happens. [2]

10 © UCLES 2012 0653/22/M/J/12 For Examiner's Use 6 A car is travelling along a road. (a) Many forces act on the car. (i) State two effects that forces can have on an object. 1 2 [2] (ii) State the unit used to measure force. [1] (b) Fig. 6.1 shows a car travelling in a straight line. The car is decelerating (slowing down). F B Fig. 6.1 The total forward force on the car is F and the total backward force is B. Which force is greater, F or B? Explain your answer. [1]

11 © UCLES 2012 0653/22/M/J/12 [Turn over For Examiner's Use (c) Using some of the words below, complete the sentences to explain the energy changes which take place in a car when petrol (gasoline) is used to power the car. boiled burned cooled chemical heat kinetic nuclear sound Petrol (gasoline) contains energy. The petrol is in the engine to produce heat energy. The heat energy is changed into energy which moves the car. This process is not very efficient and much energy is wasted as energy and energy. [5] (d) Petrol (gasoline) is a mixture of hydrocarbons. Explain why the mixture of waste gases (exhaust gases) from a car contains carbon dioxide and water vapour. [2]

12 © UCLES 2012 0653/22/M/J/12 For Examiner's Use 7 Hawksbill turtles are an endangered species. They lay their eggs in nests in the sand on a beach. sand sea The sex of hawksbill turtles is determined by the temperature of the sand in which the eggs develop. • At 29 °C, equal numbers of males and females develop. • Higher temperatures produce more females. • Lower temperatures produce more males. (a) Researchers measured the temperature, at a depth of 30 cm, in two different parts of a beach, on Antigua, where hawksbill turtles lay their eggs. The results are shown in Fig. 7.1. The tops of the bars represent the mean temperature. 30.0 29.0 28.0 27.0 open sand part of beach forest mean temperature / °C Fig. 7.1

13 © UCLES 2012 0653/22/M/J/12 [Turn over For Examiner's Use With reference to Fig. 7.1, describe the effect of the forest on the temperature of the sand. [2] (b) The researchers counted the proportion of male and female turtles hatching from nests in the two different parts of the beach. The results are shown in Table 7.1. Table 7.1 part of beach nests producing more males than females nests producing more females than males nests producing equal numbers of females and males open sand 0 16 0 in forest 36 0 0 Use the information in Fig. 7.1 to explain the results for nests in open sand and in forest, shown in Table 7.1. [2] (c) Suggest why hawksbill turtles might become extinct if all the forest by the beaches is cut down. [2] (d) State two harmful effects to the environment, other than extinction of species, that can result from deforestation. 1 2 [2]

14 © UCLES 2012 0653/22/M/J/12 For Examiner's Use 8 Fig. 8.1 shows apparatus a student used to investigate temperature changes that occurred during chemical reactions. insulated beaker thermometer reaction mixture Fig. 8.1 The student added reactants to the insulated beaker and stirred the mixture. She recorded the final temperature of each mixture. At the start of each experiment, the temperature of the reactants was 22 °C. Table 8.1 contains the results the student obtained. Table 8.1 experiment reactant A reactant B final temperature / °C 1 dilute hydrochloric acid sodium hydrogencarbonate 16 2 dilute hydrochloric acid potassium hydroxide solution 26 3 magnesium copper sulfate solution 43 4 copper magnesium sulfate solution 22 (a) (i) Explain which experiment, 1, 2, 3 or 4, was a neutralisation reaction between an acid and an alkali. experiment explanation [1]

15 © UCLES 2012 0653/22/M/J/12 [Turn over For Examiner's Use (ii) State and explain which experiment, 1, 2, 3 or 4, was an endothermic reaction. experiment explanation [1] (iii) Suggest why the temperature did not change when copper was added to magnesium sulfate solution. [1] (b) The student used the apparatus in Fig. 8.1 to carry out two further experiments, 5 and 6, to investigate the exothermic reaction between zinc and copper sulfate solution. In experiment 5 the student used zinc powder and in experiment 6 she used a single piece of zinc. The mass of zinc in both experiments was the same. Suggest and explain briefly in which experiment, 5 or 6, the temperature increased more quickly. experiment explanation [2]

16 © UCLES 2012 0653/22/M/J/12 For Examiner's Use 9 (a) Explain what is meant by the term enzyme. [2] (b) Fig. 9.1 shows the effect of pH on the activity of an enzyme. rate of reaction 1 2 3 4 5 pH 6 7 8 9 10 11 12 0 Fig. 9.1 Describe the effect of pH on the activity of this enzyme. [2] (c) An enzyme works in the human stomach, where hydrochloric acid is secreted. This enzyme is adapted to work best in these conditions. (i) On Fig. 9.1, sketch a curve to show how pH affects the activity of this stomach enzyme. [1] (ii) After the food has been in the stomach for a while, it passes into the duodenum. Pancreatic juice, which contains sodium hydrogencarbonate, is mixed with the food in the duodenum. Explain why the stomach enzyme stops working when it enters the duodenum. [2]

17 © UCLES 2012 0653/22/M/J/12 For Examiner's Use (d) Enzymes in the human digestive system help to break down large food molecules into smaller molecules. Explain why this is important. [2]

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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 2012 0653/22/M/J/12 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 May/June 2012 question paper for the guidance of teachers 0653 COMBINED SCIENCE 0653/22 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 May/June 2012 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 – May/June 2012 0653 22 © University of Cambridge International Examinations 2012 1 (a) (i) argentite and galena (or formulae) ; [1] (ii) scheelite (or formula) ; [1] (b) each particle correctly labelled ;; [2] (c) (i) heat given off / exothermic / temperature increases ; effervescence / fizzing / gas given off ; sodium (reacts and) dissolves ; [max 2] (ii) faster / more violent / greater temperature rise / reference to (lilac) flame ; [1] (iii) → potassium hydroxide + hydrogen ;; [2] [Total: 9] 2 (a) suitable units ; suitable labelled axes ; all points plotted correctly ; 3 correct lines drawn ; [4] (b) (i) water / sweat turns to gas / (water) vapour ; heat is needed / used to cause evaporation ; heat is obtained / taken / comes from (athlete’s) body / so heat in (athlete’s) body is reduced ; accept answers based on particle theory. [max 2] (ii) (higher) temperature ; (lower) humidity ; (greater) wind speed ; (greater) surface area ; [max 2] [Total: 8] 3 (a) (chemical reactions that) break down nutrient (molecules) / glucose ; to release energy ; [2] (b) gas percentage in inspired air percentage in expired air oxygen ; 21 17 carbon dioxide ; 0.04 4 nitrogen ; 78 78 [3]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0653 22 © University of Cambridge International Examinations 2012 (c) diffusion in the lungs ; in red blood cells ; combined with / attached to, haemoglobin ; [max 2] (d) (i) increases pulse rate / makes heart beat faster ; [1] (ii) anything related to fear or excitement ; [1] (iii) liver ; [1] [Total: 10] 4 (a) transverse / longitudinal / difference frequency / wavelength / different speed ; [1] (b) radiation gamma microwave infra-red x-rays uses examining bones and teeth remote controls for television sets satellite communications sterilising surgical instruments all correct 3 marks / three or two correct 2 marks / one correct 1 mark ;;; [3] (c) (i) (speed =) distance / time ; = 500 / 1.5 = 333 (m / s) ; [2] (ii) between 10 and 20 (Hz) to between 20 000 and 25 000 (Hz) ; [1] (iii) (density =) mass / volume ; = 10 000 / 1.1 = 9091 (kg / m3) ; [2] [Total: 9]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0653 22 © University of Cambridge International Examinations 2012 5 (a) use of chlorine / ozone / ultrafiltration / boiling ; removes / kills harmful microorganisms ; OR filtration ; removes insolubles ; [max 2] (b) in water (molecules) hydrogen (atoms) are bonded to oxygen (atoms) ; in the mixture only like atoms are bonded ; OR in water the H:O ratio is 2:1 ; in the mixture no fixed ratio ; OR (chemical) properties of compound are different from those of the elements it contains ; mixture retains properties of elements it contains ; [max 2] (c) (i) heat / boil / leave ; water evaporates / leaving crystals ; [2] (ii) (no) hexane is a liquid (at room temperature) ; so also passes through filter ; [2] (d) (i) it gains electrons ; [1] (ii) magnesium oxide reacted with the water ; and formed, an alkaline solution / product / magnesium hydroxide ; [2] [Total: 11] 6 (a) (i) change shape ; change speed / start object moving / stop object moving / acceleration etc ; change direction (of motion) of object ; [max 2] (ii) newton ; [1] (b) B (no mark) ; car is decelerating, (force) B as is greater than (force) F ; [1] (c) chemical ; burned ; kinetic ; heat ; sound ; [5]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0653 22 © University of Cambridge International Examinations 2012 (d) reaction between the fuel / gasoline and oxygen / air / complete combustion ; carbon reacts with oxygen to give carbon dioxide ; hydrogen reacts with oxygen to give water ; carbon dioxide and water are (combustion) products / products of burning ; [max 2] [Total: 11] 7 (a) trees shade sand ; reduces the temperature ; reference to figures from the graph / quantitative comparison ; [max 2] (b) open sand is hotter and so produced more females ; forest cooler and so produced more males ; [2] (c) deforestation will result in hotter / more open sand ; so more female turtles produced ; which might make breeding difficult / might reduce number of young born ; [max 2] (d) increased carbon dioxide / effects of increased carbon dioxide ; less oxygen (in the atmosphere) ; (more soil) erosion / landslides ; (more) flooding ; [max 2] [Total: 8] 8 (a) (i) (expt. 2) potassium hydroxide is an alkali ; [1] (ii) (expt 1) temperature decreased ; [1] (iii) no reaction occurred / no energy was transferred ; copper is less reactive than magnesium (so no reaction) ; [max 1] (b) (expt 5) the rate of reaction was greater ; so energy was transferred more quickly / temperature increases more quickly ; because powder has greater surface area ; [max 2] [Total: 5]

Page 6 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0653 22 © University of Cambridge International Examinations 2012 9 (a) catalyst ; biological / that works in living organisms ; protein ; [max 2] (b) greatest activity at pH 6.5 ; no activity at below pH 4 / above pH 9 ; [2] (c) (i) curve of similar shape with peak at pH 4 or below ; [1] (ii) sodium hydrogencarbonate neutralises / reacts with the acid / sodium hydrogencarbonate is a base ; so pH rises (above optimum for enzyme) / becomes too alkaline / pH too high ; [2] (d) so they can be absorbed ; into cells / into the blood / to be carried round the body ; [2] [Total: 9]