Cambridge IGCSE Science - Combined 0653 — 2007 Oct/Nov Paper 2 · Variant 1

This document consists of 19 printed pages and 1 blank page. IB07 11_0653_02/2RP © UCLES 2007 [Turn over *6389050490* 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 0653/02 Paper 2 (Core) October/November 2007 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 2007 0653/02/O/N/07 For Examiner's Use 1 Fig. 1.1 shows a plant, and also a cell from part of the plant. A B C D Fig. 1.1 (a) From which part of the plant, A, B, C or D, does the cell come? [1] (b) On the diagram of the cell in Fig. 1.1, label the following structures. Use label lines and the appropriate letters. P a partially permeable membrane Q the part of the cell that contains DNA R a structure where energy from sunlight is absorbed [3]

3 © UCLES 2007 0653/02/O/N/07 [Turn over For Examiner's Use (c) Describe how you would test a leaf from the plant for starch. [3] (d) Complete these sentences about part A of the plant shown in Fig. 1.1. Use some of these words. anthers asexual ovules petals sepals sexual stigma Flowers are responsible for reproduction. The make pollen, which contains the male gametes. The female gametes are found inside the [3]

4 © UCLES 2007 0653/02/O/N/07 For Examiner's Use 2 Fig. 2.1 shows the inside of a refrigerator. freezing compartment Fig. 2.1 (a) (i) Draw arrows on Fig. 2.1 to show what happens to the air cooled by the freezing compartment. [1] (ii) Name this method of heat transfer. [1] (iii) Use the idea of density to explain why this happens. [2] (b) The refrigerator has a lamp inside. The supply voltage is 240 V and the current passing through the lamp when lit is 0.04 A. Calculate the resistance of the lamp. State the formula that you use and show your working. formula used working Ω [2]

5 © UCLES 2007 0653/02/O/N/07 [Turn over For Examiner's Use (c) The refrigerator walls are insulated using both expanded polystyrene and aluminium foil. inner wall outer wall aluminium foil expanded polystyrene Explain how the structure of the refrigerator wall will help to maintain a lower temperature inside the refrigerator. [3]

6 © UCLES 2007 0653/02/O/N/07 For Examiner's Use 3 Hydrogen peroxide, H2O2, is a colourless liquid. Hydrogen peroxide slowly decomposes into simpler substances. The equation for the decomposition reaction is shown below. hydrogen peroxide → water + oxygen (a) How many atoms are there in one molecule of hydrogen peroxide? [1] (b) (i) The decomposition of hydrogen peroxide is usually carried out in the presence of a catalyst. State the purpose of adding a catalyst to a reaction mixture. [1] (ii) The solid compound manganese dioxide, MnO2, is used as a catalyst in the reaction above. Manganese is a metal in the fourth period of the Periodic Table. What name is given to the family of metals which contains manganese? [1]

7 © UCLES 2007 0653/02/O/N/07 [Turn over For Examiner's Use (c) (i) Hydrogen peroxide contains two non-metallic elements bonded together. Name the type of chemical bonding in hydrogen peroxide molecules. [1] (ii) Oxygen molecules, O2, are made of two oxygen atoms joined by a double bond. Suggest the displayed formula of an oxygen molecule. [1] (iii) The symbolic equation for the decomposition of hydrogen peroxide is shown below. The equation is not balanced. Balance the equation. …H2O2 …H2O + O2 [1]

8 © UCLES 2007 0653/02/O/N/07 For Examiner's Use 4 Fig. 4.1 shows part of the carbon cycle. fossil fuels carbon dioxide in atmosphere X Fig. 4.1 (a) Name the process labelled X on Fig. 4.1. [1] (b) Explain how carbon dioxide is returned to the air from the bodies of dead organisms. [2] (c) Describe how fossil fuels are formed. [2]

9 © UCLES 2007 0653/02/O/N/07 [Turn over For Examiner's Use (d) Fig. 4.2 shows changes in the concentration of carbon dioxide in the atmosphere in the last 160 000 years. 400 350 300 250 200 150 160 000 120 000 80 000 40 000 0 carbon dioxide concentration / p.p.m. years before the present time Fig. 4.2 (i) Suggest one human activity that is causing the current increase in carbon dioxide concentration in the atmosphere. [1] (ii) Explain how the information in Fig. 4.2 suggests that human activities are not entirely to blame for increases in the concentration of carbon dioxide in the atmosphere. [1] (iii) Explain why many people are worried about this increase in carbon dioxide concentration. [2]

10 © UCLES 2007 0653/02/O/N/07 For Examiner's Use 5 A space rocket is launched to the Moon. (a) After launch, the empty fuel tanks are released and fall back to Earth. As a tank falls, two forces act on it as shown in Fig. 5.1. F1 F2 fuel tank Fig. 5.1 (i) Name forces F1 and F2. F1 F2 [2] (ii) As it falls, the tank accelerates. What does this tell you about the two forces? [1] (b) The rocket travels 400 000 km to the Moon in 80 hours. Calculate the average speed of the rocket. State the formula that you use and show your working. formula used working km / h [2]

11 © UCLES 2007 0653/02/O/N/07 [Turn over For Examiner's Use (c) One of the astronauts on the rocket has a mass of 90 kg. The gravitational field strength of the Moon is about one-sixth that of the Earth. State the differences, if any, between (i) the mass of the astronaut on the Earth and on the Moon, [1] (ii) the weight of the astronaut on the Earth and on the Moon. [1] (d) There is no atmosphere and there are no fossil fuel deposits on the Moon. To provide the energy needed to use his equipment on the Moon, the astronaut needs to use renewable energy resources. Suggest one renewable energy resource which is naturally available on the Moon. [1]

12 © UCLES 2007 0653/02/O/N/07 For Examiner's Use 6 The apparatus in Fig. 6.1 can be used to study the reaction between potassium and oxygen. flask potassium reacting with oxygen reaction products Fig. 6.1 (a) Suggest why the flask becomes warm during the reaction. [1] (b) One of the compounds formed in this reaction is potassium oxide. The chemical formula of potassium oxide is K2O. (i) Explain the meaning of this formula. [1] (ii) Potassium oxide is made of positive and negative ions. Explain, in terms of protons and electrons, the difference between a positive ion and a neutral atom. [2]

13 © UCLES 2007 0653/02/O/N/07 [Turn over For Examiner's Use (c) When the reaction in Fig. 6.1 had finished, a student added water containing Universal Indicator to the flask. Predict the colour change of the Universal Indicator. Explain your prediction. [2] (d) Potassium metal reacts with water to form a solution of potassium hydroxide. During the reaction a gas is given off. (i) Write the chemical formula of potassium hydroxide. [1] (ii) Name the gas which is given off and describe a test for this gas. name of gas test [3]

14 © UCLES 2007 0653/02/O/N/07 For Examiner's Use 7 Tuberculosis (TB) is an infectious disease caused by a bacterium. HIV/AIDS is caused by a virus. (a) Table 7.1 shows the percentage of people with TB and HIV/AIDS in four parts of the world in 2005. Table 7.1 part of the world percentage of people with TB percentage of people with HIV/AIDS sub-Saharan Africa 0.51 7.2 Southeast Asia 0.35 1.1 Americas 0.07 0.7 Europe 0.06 0.5 (i) In which of these four parts of the world was there the largest percentage of people with TB? [1] (ii) Describe any pattern that seems to link the percentages of people with TB and with HIV/AIDS. [1] (iii) The virus that causes AIDS infects white blood cells. Explain how this could be responsible for the pattern that you have described in (ii). [2] (b) The TB bacterium usually infects cells in the lungs. Many of the cells in the alveoli are destroyed. Explain how this can lead to a person feeling very tired and unable to carry out energetic exercise. [2]

15 © UCLES 2007 0653/02/O/N/07 [Turn over For Examiner's Use (c) (i) HIV/AIDS can be transmitted through sexual intercourse. Name two other diseases that can be transmitted in this way. 1. 2. [2] (ii) How can the spread of these diseases be reduced? [1]

16 © UCLES 2007 0653/02/O/N/07 For Examiner's Use 8 A student is having a medical examination. (a) A dentist checks the student’s teeth using a dental mirror. This is shown in Fig. 8.1. dentist’s eye mirror tooth A Fig. 8.1 Draw a ray of light from the back of tooth A to the dentist’s eye to show how the dentist is able to see the back of the tooth. On the ray, draw arrows showing the direction in which the light travels. [3] (b) A doctor tests the student’s hearing and confirms that the lowest and highest frequencies the student can hear are normal for a young person. (i) Suggest a value for each of these. lowest frequency Hz highest frequency Hz [2] (ii) What is meant by the frequency of a wave? [1] (iii) Sound is one form of energy. Name two other forms of energy. 1. 2. [1]

17 © UCLES 2007 0653/02/O/N/07 [Turn over For Examiner's Use (c) The doctor wants to use a small torch to look down the student’s throat. When he switches the torch on, it does not work. Fig. 8.2 shows the circuit diagram for the torch. Fig. 8.2 (i) Explain what is wrong with the torch. [1] (ii) Draw the correct circuit diagram. [1]

18 © UCLES 2007 0653/02/O/N/07 For Examiner's Use 9 Aluminium, iron, sodium and chlorine are important elements produced by the chemical industry. (a) Use the copy of the Periodic Table on page 20 to help you to answer this question. State which of the elements above (i) is not in the same period of the Periodic Table as the other three, [1] (ii) has atoms which contain 11 electrons. [1] (b) Aluminium is a metal which resists corrosion and has a relatively low density. The strength of aluminium can be improved by making it into an alloy. Explain why aluminium alloys are important materials for use in aircraft construction. [3] (c) Iron is produced when iron oxide reacts with carbon monoxide in a blast furnace. Most iron is converted into steel. (i) The equation for the reaction between iron oxide and carbon monoxide is shown below. iron oxide + carbon monoxide → iron + carbon dioxide Explain which substance has been reduced in this reaction. [2] (ii) State two advantages of steel compared to iron from a blast furnace. 1. 2. [2] (d) The chemical symbol for chlorine is Cl. Write the chemical formula of a chlorine molecule. [1]

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 2007 0653/02/O/N/07 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 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 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 2007 question paper 0653 COMBINED SCIENCE 0653/02 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. All Examiners are instructed that alternative correct answers and unexpected approaches in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and skills demonstrated. 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 2007 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 Syllabus Paper IGCSE – October/November 2007 0653 02 © UCLES 2007 1 (a) leaf / C ; [1] (b) P to cell membrane / vacuole membrane ; Q to nucleus ; R to chloroplast ; [3] (c) add to boiling water ; then to hot alcohol ; rinse in water ; add iodine (solution) ; blue/black colour produced; [max 3] (d) sexual ; anthers ; ovules ; [3] 2 (a) (i) arrows going down/convection current with cold air direction labeled; [1] (ii) convection; [1] (iii) (cold air) is denser/ has particles which are closer together; flows / drops to bottom of fridge; displaces warmer air; [2] (b) R = V ÷ I / resistance = volts ÷ current/amps; = 240 ÷ 0.04=6000 (Ω); [2] (c) aluminium reflects radiation back; polystyrene stops heat traveling through; by conduction /convection; (salvage mark, if none of above then one mark for saying that the structure is preventing heat from the outside entering the refrigerator) [3] 3 (a) 4; [1] (b) (i) speeds up the reaction; [1] (ii) transition metals; [1] (c) (i) covalent; [1] (ii) O=O / fully correct dot and cross diagram; [1] (iii) ..2. H2O2 → ..2. H2O + O2; [1]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0653 02 © UCLES 2007 4 (a) respiration ; [1] (b) by decomposition (of dead organisms / bodies); decay organisms / detritivores / decomposers ; example of decomposer e.g. bacteria/fungi; respire ; [max 2] (c) dead / once living organisms / plants / animals / bacteria ; do not decay fully ; in anaerobic / airless / absence of oxygen / waterlogged conditions ; idea that they are compressed and buried ; reference to long timescale [max 2] (d) (i) burning fossil fuels / named fossil fuel / other fuels e.g. wood; [1] (ii) carbon dioxide concentration rose before humans were burning fossil fuels / clear implication that carbon dioxide levels high in the past (before possibility of human activity); [1] (iii) global warming / temperature rise / worsening of greenhouse effect; one effect mentioned, e.g. sea level rise ; [2] 5 (a) (i) weight / gravity; friction/air resistance; [2] (ii) weight / gravity is greater than air resistance / F1 greater than F2; [1] allow ecf (b) (average) speed = distance/time; = 400 000/80= 5000 km/h; [2] (c) (i) there is no difference; [1] (ii) weight will be less on the moon / 900N on earth 150N on moon / different because gravity lower on moon; [1] (d) solar energy / sunlight; [1]

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0653 02 © UCLES 2007 6 (a) reaction is exothermic / gives out heat (energy) / because of the heat released; [1] (b) (i) the idea that there are two potassium atoms / ions for every one oxygen / two potassium particles are bonded to one oxygen/oxide; [1] (ii) atom has same number of protons as electrons; positive ion has more protons than electrons; [2] (c) (green) to purple / blue; (metal oxides produce) alkaline solutions; [2] (d) (i) KOH; [1] (ii) hydrogen; lighted splint; pops; [3] allow ecf for correct test /result on incorrect gas 7 (a) (i) sub-Saharan Africa ; [1] (ii) the more HIV/AIDS, the more TB ; [1] (iii) immune system cannot work properly / T cells do not work; unable to destroy TB bacterium ; [2] (b) less oxygen taken in ; oxygen needed for energy release by respiration ; [2] (c) (i) gonorrhoea ; syphilis ; (accept others e.g. chlamydia, genital warts, herpes) [2] (ii) use of condom / keeping to one partner / abstinence if a person has HIV / use of antibiotics; [1] also allow the term, preservative, protection

Page 5 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0653 02 © UCLES 2007 8 (a) arrows in right direction; ray of light from tooth to mirror and mirror to eye; approx correct angles; [3] (b) (i) a value in the range 10 to 20 Hz; a value in the range 20 000 to 25 000Hz; [2] (ii) number of waves produced/passing per second; [1] (iii) light/heat/thermal/nuclear/electrical/kinetic/potential/chemical; [1] (c) (i) one cell is back to front; ignore reference to blown bulb. [1] (ii) [1]

Page 6 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0653 02 © UCLES 2007 9 (a) (i) iron/Fe; [1] (ii) sodium/Na; [1] (b) alloy is a light material/ has a low density; low mass material need for planes; less fuel needed; alloy is stronger; alloy resists corrosion; (allow does not corrode but reject the word rust) aircraft does not break up in flight; [max 3] (c) (i) iron oxide; reduction is loss of oxygen / or strong implication; [2] (also allow description of electron gain by iron ions / Fe3+) (ii) steel is stronger; steel is less brittle; steel is more resistant to corrosion; (allow it does not rust) [max 2] (d) Cl2; [1]