Cambridge IGCSE Science - Combined 0653 — 2012 May/June Paper 2 · Variant 3

This document consists of 22 printed pages and 2 blank pages. IB12 06_0653_23/FP © UCLES 2012 [Turn over * 8777286815* 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 0653/23 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 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 2012 0653/23/M/J/12 For Examiner's Use 1 Sugar cane is a food crop grown in Australia. It is harvested and then transported on small trains to the processing plant. Fig. 1.1 shows one of the trains carrying sugar cane. Fig. 1.1 (a) The train travels a distance of 25 kilometres in 2 hours. Calculate the average speed of the train. State the formula that you use and show your working. formula used working km / h [2] (b) The train engine is powered by oil. The oil is burned to change water into steam. The steam is used to make parts of the engine move. (i) What kind of energy is stored in the oil? [1] (ii) The engine is 30 % efficient in converting the energy stored in the oil into movement energy. The rest of the stored energy is lost in different ways. State one of these ways. [1]

3 © UCLES 2012 0653/23/M/J/12 [Turn over For Examiner's Use (c) The track for the train is composed of short lengths of steel rails with small gaps left between them as shown in Fig. 1.2. gap steel rail Fig. 1.2 Suggest a reason for leaving these small gaps. [2] (d) Sugar can be fermented and turned into ethanol. Ethanol is now used as a fuel for cars. Give one reason, other than cost, why people might use ethanol rather than petrol in their cars. [1]

4 © UCLES 2012 0653/23/M/J/12 For Examiner's Use (e) The farm on which the sugar cane is grown uses a wind turbine to produce electrical power. Table 1.1 shows the electrical power generated for different wind speeds. Table 1.1 wind speed / km per hour 0 3 5 8 10 12 15 20 power generated / W 0 0 150 500 1000 1100 1200 1200 (i) Suggest the lowest wind speed needed to generate power. km / h [1] (ii) State the maximum power that this wind turbine can produce. W [1] (iii) State one disadvantage of using only a wind turbine as the source of electrical power. [1]

5 © UCLES 2012 0653/23/M/J/12 [Turn over For Examiner's Use 2 An element is a substance that is made of atoms which have the same proton number. Most atoms contain protons, neutrons and electrons. The elements are shown in the Periodic Table. (a) The chemical symbol of an atom of the element chlorine is shown below. Cl 35 17 The nucleon number of this atom is 35. (i) Name the part of an atom that contains the protons and neutrons. [1] (ii) State the number of neutrons in this chlorine atom. Explain your answer. number of neutrons explanation [2] (iii) Name the element whose atoms do not usually contain any neutrons. [1] (b) Table 2.1 shows Period 2 of the Periodic Table. Table 2.1 X Period 2 I II III IV V VI Y VII Z 0 The element represented by X is a solid at room temperature and the elements represented by Y and Z are gases. (i) Suggest one difference, other than physical state at room temperature, between the properties of elements X and Y. [1] (ii) Suggest one difference between the chemical properties of elements Y and Z. [1]

6 © UCLES 2012 0653/23/M/J/12 For Examiner's Use (c) Fig. 2.1 shows a simple lime kiln which is used to produce lime (calcium oxide) from limestone (calcium carbonate). waste gases air calcium carbonate carbon burns to provide heat energy Fig. 2.1 In the lime kiln, the pieces of carbon are burnt to provide heat energy. (i) Explain why the burning of carbon is described as an oxidation reaction. [2] (ii) Both calcium oxide and calcium carbonate are sometimes added to the soil by farmers. Suggest and explain why this is done. [2]

7 © UCLES 2012 0653/23/M/J/12 [Turn over For Examiner's Use 3 Marmots are herbivorous mammals. Fig. 3.1 shows a marmot. Fig. 3.1 (a) Define the term herbivore. [2] (b) A study has been carried out on the marmots living in Colorado, USA. The winters in this part of Colorado are very cold. The marmots hibernate (sleep) in burrows in winter. They do not eat while they are hibernating. They wake up in spring. Before they hibernate, marmots build up large fat stores beneath their skin. Suggest and explain what marmots must do in order to build up large fat stores in their bodies. [2]

8 © UCLES 2012 0653/23/M/J/12 For Examiner's Use (c) Fig. 3.2 shows the percentage of marmots with different body masses that survive through the winter. 100 80 60 40 percentage of marmots surviving body mass / kg 2 3 4 5 Fig. 3.2 (i) Describe the relationship between a marmot's body mass and its chance of surviving the winter. [2] (ii) Suggest how a layer of fat beneath the skin can help a marmot to keep warm during cold weather. [1] (d) In the last twenty years, spring has been arriving earlier in the year in Colorado. This is a result of global warming. Name two gases that contribute to global warming. 1 2 [2]

9 © UCLES 2012 0653/23/M/J/12 [Turn over For Examiner's Use (e) Fig. 3.3 shows the mean body mass of the marmots on the first day of August (during summer) between 1976 and 2006. 3.5 3.0 2.5 2.0 mean body mass / kg 1976 1986 1996 2006 Fig. 3.3 (i) Describe the general trend shown in Fig. 3.3. [1] (ii) Suggest how the earlier arrival of spring could be responsible for this trend. [1]

10 © UCLES 2012 0653/23/M/J/12 For Examiner's Use 4 Fig. 4.1 shows some of the apparatus and substances a student used to investigate the rate of reaction between magnesium and dilute hydrochloric acid. In this reaction a gas is given off and bubbles up into the measuring cylinder. water measuring cylinder dilute hydrochloric acid stopwatch bung magnesium Fig. 4.1 (a) Fig. 4.1 shows the apparatus just before the student started his experiment to measure the rate of reaction. Describe briefly the method the student should use and the measurements he should make. [3]

11 © UCLES 2012 0653/23/M/J/12 [Turn over For Examiner's Use (b) The student carried out a second experiment using hydrochloric acid which had a higher concentration. All of the other variables which could affect the rate were kept the same as in the first experiment. (i) State one of the other variables that the student kept constant. [1] (ii) Predict and explain briefly how the results the student obtained in the second experiment would be different from the first experiment. [2] (c) The reaction between magnesium and dilute hydrochloric acid also produces the ionic compound magnesium chloride. In crystals of this compound, two chloride ions combine with one magnesium ion. (i) State one difference between a magnesium atom and a magnesium ion. [1] (ii) State the chemical formula of magnesium chloride. [1] (iii) Complete the word chemical equation for the reaction between magnesium and hydrochloric acid. magnesium + + hydrochloric acid magnesium chloride [1]

12 © UCLES 2012 0653/23/M/J/12 For Examiner's Use 5 (a) A bat produces a sound wave with a frequency of 212 kHz and a wavelength of 0.0016 m. (i) This sound is outside the audible frequency range for humans. State the approximate audible frequency range for humans. Hz [1] (ii) State the meaning of the terms frequency and wavelength, when describing a wave. You may use a diagram if it helps your explanation. frequency wavelength [2]

13 © UCLES 2012 0653/23/M/J/12 [Turn over For Examiner's Use (b) A girl shouts and waves to another girl in the school playground as shown in Fig. 5.1. Fig. 5.1 The sound energy and the light energy both travel from one girl to the other by wave motion. (i) Explain why sound waves will not travel through a vacuum. [1] (ii) If the first girl now makes another sound with a smaller amplitude, what change would the second girl notice? [1] (iii) The girls could have communicated with each other using their mobile phones (cell phones). Name the type of electromagnetic wave used to communicate between mobile phones. [1]

14 © UCLES 2012 0653/23/M/J/12 For Examiner's Use (c) Fig. 5.2 shows a ray of light passing through a rectangular glass block. normal normal Fig. 5.2 On Fig. 5.2, label an angle of incidence, i, and an angle of refraction, r. [2]

15 © UCLES 2012 0653/23/M/J/12 [Turn over BLANK PAGE Please turn over for Question 6.

16 © UCLES 2012 0653/23/M/J/12 For Examiner's Use 6 Fig. 6.1 shows part of a section across a root from a radish plant, photographed through a microscope. Fig. 6.1 (a) On Fig. 6.1, use a label line to label a root hair cell. [1] (b) Root hair cells absorb substances from the soil. Name two substances that root hair cells absorb from the soil. 1 2 [2] (c) A complete radish plant was placed with the lower part of the root standing in water. A soluble red dye was added to the water. After a while, the veins in the leaves of the radish plant became red. (i) Name the tissue in the radish plant through which the coloured water was transported from the roots to the leaves. [1] (ii) On Fig. 6.1, write the letter A to show the position of this tissue in the root. [1]

17 © UCLES 2012 0653/23/M/J/12 [Turn over For Examiner's Use (d) (i) The cells in the radish root are plant cells. Complete Table 6.1 to show which structures are present in plant cells and which are present in animal cells. Use a tick ( ) to show that the structure is present. Use a cross ( ) to show that the structure is not present. You should place either a tick or a cross in every space in the table. Table 6.1 structure plant cells animal cells cell membrane cell wall nucleus vacuole containing sap [4] (ii) Would you expect the cells in the radish root to contain chloroplasts? Explain your answer. [1]

18 © UCLES 2012 0653/23/M/J/12 For Examiner's Use 7 (a) A student investigated how the change in potential difference across a lamp affected the current flowing through it. She used wires to connect the components shown in Fig. 7.1 to make a suitable circuit. A V Fig. 7.1 (i) Using the correct symbols from Fig. 7.1, draw a diagram to show the circuit she made. [3] (ii) Explain why a variable resistor is used in this circuit. [1]

19 © UCLES 2012 0653/23/M/J/12 [Turn over For Examiner's Use (b) A plastic rod is rubbed with a cloth. The rod becomes charged. There are two types of electric charge. (i) State the names of these types of charge. 1 2 [1] (ii) Charged particles are transferred between the rod and cloth. Name the charged particles transferred. [1] (iii) Plastic is an example of an electrical insulator. Name one material which is an electrical conductor. [1]

20 © UCLES 2012 0653/23/M/J/12 For Examiner's Use 8 The bar chart in Fig. 8.1 shows the approximate composition of unpolluted air. nitrogen … % oxygen … % other gases … % percentage in unpolluted air Fig. 8.1 (a) (i) Complete the bar chart in Fig. 8.1 by labelling the percentages of nitrogen, oxygen and other gases. [2] (ii) Name one of the other gases in Fig. 8.1 that exists in unpolluted air. [1] (b) Nitrogen and oxygen exist in the air in the form of the diatomic molecules, N2 and O2. When lightning passes through the air, the gaseous compounds nitric oxide, NO, and nitrogen dioxide, NO2, are formed. NO NO NO NO2 NO NO2 NO NO NO NO2 NO2 NO (i) Explain why nitrogen and oxygen are described as chemical elements, but nitric oxide and nitrogen dioxide are described as compounds. [2]

21 © UCLES 2012 0653/23/M/J/12 For Examiner's Use (ii) Suggest the type of chemical bonding in nitric oxide and nitrogen dioxide. Explain your answer briefly. type of bonding explanation [2] (iii) Nitrogen dioxide dissolves and reacts with rainwater. A student carried out an experiment to investigate what happened to the acidity of rainwater during a thunderstorm. His results are shown in Table 8.1. Table 8.1 description of sample pH pure water obtained in a science laboratory 7 rainwater collected when no thunderstorm was occurring 5 rainwater collected during a thunderstorm 4 What conclusions can the student make from these results? [2]

22 © UCLES 2012 0653/23/M/J/12 For Examiner's Use 9 (a) One of the characteristics of living organisms is sensitivity. This is the ability to respond to changes in the environment. List four other characteristics of all living things. 1 2 3 4 [2] (b) Hormones help organisms to respond to changes in their environment. (i) Name the hormone that is produced when a person is frightened. [1] (ii) State two effects of this hormone. 1 2 [2] (c) How are hormones transported around the body? [1]

23 Copyright Acknowledgements: Question 6 Photograph © B23WP8 cross section of a radish root; Biodisc/Visuals Unlimited/Alamy. 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 0653/23/M/J/12 BLANK PAGE

24 © UCLES 2012 0653/23/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 0653/23 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. • 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 23 © University of Cambridge International Examinations 2012 1 (a) (speed =) distance / time ; = 25 / 2 = 12.5 (km / h) ; [2] (b) (i) chemical ; [1] (ii) heating engine / heating surroundings / light / sound ; [1] (c) metal track expands in summer / hot weather ; metal can expand into gap ; prevents damage to tracks ; [max 2] (d) ethanol is renewable source / no sulfur dioxide produced ; [1] (e) (i) 5 (km / h) ; (accept 4 / reference to greater than 3 but equal to and less than 5) [1] (ii) 1200 (W) ; [1] (iii) wind speed variable / wind unreliable / owtte ; [1] [Total: 10] 2 (a) (i) nucleus ; [1] (ii) 18 ; evidence of neutrons = nucleon number minus proton number ; [2] (iii) hydrogen ; [1] (b) (i) any typical metal property for X and corresponding non-metal for Y ; [1] e.g. X conductor Y insulator X malleable Y not malleable (ii) Y is reactive / specific example, Z is unreactive ; [1] (c) (i) reference to oxygen (not air) ; which joins / reacts with carbon ; [2] (ii) soil (too) acidic ; lime, reacts with / neutralises acid / reduces acidity ; to increase fertility ; [max 2] [Total: 10]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0653 23 © University of Cambridge International Examinations 2012 3 (a) an animal that eats plants ; only eats plants / does not eat meat ; reference to getting energy from, its food / plants ; [max 2] (b) eat a lot ; eat / take in, more energy than they use ; excess, carbohydrate / protein, converted to fat ; [max 2] (c) (i) the greater the body mass, the greater the chance of survival ; idea that effect is greater at lower body masses / levels off at higher body masses ; use of figures ; [max 2] (ii) insulator / poor conductor / reduces conduction ; [1] (d) carbon dioxide ; methane ; [2] (e) (i) (mean) body mass is increasing ; [1] (ii) marmots have more time to feed (from spring onwards) / marmots lose less weight during hibernation (as winters are shorter) ; as spring arrives earlier, plants grow faster and as marmots are herbivores they have more plants to eat, therefore increasing mass ; [max 1] [Total: 11] 4 (a) add magnesium to acid ; insert bung ; measure time for known volume of gas to collect / measure volume of gas at fixed time intervals / measure how long reaction lasts ; [3] (b) (i) temperature / surface area of magnesium ; [1] (ii) time for (same volume) of gas to collect is shorter ; because rate of reaction is greater ; [2] (c) (i) ion is charged, atom is neutral / proton and electron numbers are the same in atom, but differ in the ion / the atom is reactive, the ion is stable / ion has all electron shells full, while atom outer shell is not full ; [1] (ii) MgCl2 ; [1] (iii) hydrogen ; [1] [Total: 9]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0653 23 © University of Cambridge International Examinations 2012 5 (a) (i) between 10 and 20 (Hz) to between 20 000 and 25 000 (Hz) ; [1] (ii) frequency – number of waves produced / passing a point per second ; wavelength – distance between consecutive, peaks / troughs ; [2] (b) (i) needs, air / particles / a medium ; [1] (ii) quieter / lower volume ; [1] (iii) microwaves ; [1] (c) angle of incidence labelled ; angle of refraction labelled ; [2] [Total: 8] 6 (a) label to root hair cell ; [1] (b) water ; minerals / ions / named mineral ion ; [2] (allow two different mineral ions for 2 marks) (c) (i) xylem ; [1] (ii) A in central area of root ; [1] (d) (i) structure plant cells animal cells cell membrane

cell wall
 nucleus

vacuole containing sap
 1 mark for any row correct ;;;; [4] (ii) no, as they do not get light / as they are underground ; [1] [Total: 10]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0653 23 © University of Cambridge International Examinations 2012 7 (a) (i) ammeter in series with lamp ; voltmeter in parallel with lamp ; variable resistor in series with lamp and all else correct ; [3] (ii) to change, voltage across / current through, lamp / in circuit ; [1] (b) (i) positive and negative ; [1] (ii) electrons ; [1] (iii) metal / named metal / graphite ; [1] [Total: 7] 8 (a) (i) nitrogen 78% oxygen 21% others 1% ;; [2] (all correct 2, two correct 1) (ii) carbon dioxide / water (vapour) / any noble gas ; [1] (b) (i) elements all atoms have same proton number / are found in Periodic Table / cannot be broken down into anything simpler ; compounds contain different types of atom / elements (bonded) ; [2] (ii) covalent ; bonded elements are both non-metals / compounds are gases ; [2] (iii) pure water is neutral ; rain water (generally) is (more) acidic (than pure water) ; rainwater during thunderstorm is the most acidic / owtte ; likely to be caused by nitrogen oxides ; which have reacted with the rain to form an acid ; [max 2] [Total: 9] 9 (a) nutrition excretion respiration reproduction growth movement (1 mark for any two correct) ;; [max 2] (b) (i) adrenaline ; [1] (ii) increases pulse rate ; increases blood pressure ; increases glucose in blood ; [max 2] (c) in the blood / blood vessels ; [1] [Total: 6]