Cambridge IGCSE Physical Science 0652 — 2006 Oct/Nov Paper 6 · Variant 1

Centre Number Candidate Number Name UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education PHYSICAL SCIENCE 0652/06 Paper 6 Alternative to Practical October/November 2006 1 hour 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 or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer all questions. 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. For Examiner’s Use 1 2 3 4 5 6 Total This document consists of 19 printed pages and 1 blank page. IB06 11_0652_06/5RP © UCLES 2006 [Turn over www.XtremePapers.com

2 0652/06/O/N/06 For Examiner's Use 1 A student is given a sample of powdered limestone. The student is asked to find out the amount of calcium carbonate in the sample, which also has sand in it as an impurity. He is given some dilute hydrochloric acid. He is told that 1 g of calcium carbonate will react exactly with 10.0 cm3 of the hydrochloric acid. (a) (i) A gas is given off when calcium carbonate reacts with hydrochloric acid. Name this gas. [1] (ii) State a test for this gas and the result that you would expect. [1] The student weighs out a sample of the limestone into a beaker. Fig. 1.1 shows the balance readings. 36 35 g mass of beaker Fig. 1.1 40 39 g mass of beaker + limestone (b) (i) Read the balance windows and record the readings in the spaces below. mass of beaker + limestone = g mass of beaker = g [2] (ii) Calculate the mass of limestone. mass of limestone = g [1]

3 © UCLES 2006 0652/06/O/N/06 [Turn over For Examiner's Use The student carefully adds hydrochloric acid from a burette, a few drops at a time, to the powdered limestone. (c) How can the student decide when he has added enough acid to dissolve all the calcium carbonate in the sample of limestone? [1] Fig. 1.2 shows the scale of the burette before and after the addition of the hydrochloric acid. 0 1 2 3 24 25 26 27 Fig. 1.2 (d) (i) Record the burette readings in the spaces below. second reading cm3 first reading cm3 [2] (ii) Calculate the volume of hydrochloric acid added. volume of acid added = cm3 [1] The volume of the hydrochloric acid that reacts with 1 g of calcium carbonate is 10 cm3. (e) Use the result from (d)(ii) to calculate the mass of calcium carbonate in the sample of limestone. mass of calcium carbonate = g [1]

4 0652/06/O/N/06 For Examiner's Use 2 A student did an experiment with an L-shaped piece of card. He wanted to find its centre of mass. You do not need to know the meaning of the term centre of mass. • The card was suspended on a pin pushed through a hole 5 mm from point A (distance x). A plumb-line was also hung on the pin. A B C D E F x y pin plumb-line Fig. 2.1 • When he was sure that the card was hanging freely, he marked the point at which the plumb-line crossed line FE (distance y from F). • He recorded the distances x and y in Fig. 2.2. • He moved the position of the pin towards B and repeated the experiment until he had obtained 5 sets of readings. reading number 1 2 3 4 5 x/mm 5 20 25 y/mm 67 57 53 Fig. 2.2 (a) Figs. 2.3 and 2.4 show distances x and y for the two missing readings. Measure the distances x and y and record them in Fig. 2.2. [4] B A F E reading 2 x y Fig. 2.3

5 © UCLES 2006 0652/06/O/N/06 [Turn over For Examiner's Use B A F E reading 3 x y Fig. 2.4 (b) (i) Plot a graph of y (vertical axis) against x and draw the best fit straight line. Extend the line to cut the vertical axis. [3] (ii) From the graph determine y0, the value of y when x = 0. y0 = mm [1]

6 0652/06/O/N/06 For Examiner's Use A B C D E F yo plumb-line G N M Fig. 2.5 (iii) Use the value of y0 from (ii) to mark, on Fig. 2.6, the position of the plumb-line AG. (See Fig. 2.5) Label point M, where AG crosses FC. [1] A F B C D E Fig. 2.6

7 © UCLES 2006 0652/06/O/N/06 [Turn over For Examiner's Use (c) The student thought that the centre of mass of the card was at M. He pushed the pin through the card at point M. He turned the card upside down so the pin was underneath it. The card balanced on the pin. He tried to make the card balance on point N. (See Fig. 2.5) (ii) Explain why the card would not balance on point N. [1]

8 0652/06/O/N/06 For Examiner's Use 3 The teacher gives the student samples of three solids, A, B and C. One solid is an acid, one is a base and the other is a salt. The student does three sets of experiments. He reacts A, B and C with three chemicals. He tests for any gases that are given off. (a) The three chemicals are shown in Fig. 3.1. Mark with a tick (
) where you expect a reaction to take place if they are added to an acid, to a base and to a salt. You should mark four boxes. Leave the other boxes blank. [2] chemical added sodium carbonate ammonium chloride aqueous ammonia acid base metal salt Fig. 3.1 (b) The student reacts the solids A, B and C with sodium carbonate. Fig. 3.2 shows the results. solid A with sodium carbonate in water solid B with sodium carbonate in water solid C with sodium carbonate in water No reaction is seen. The mixture bubbles and a gas is given off. The gas turns lime- water cloudy. A white precipitate is seen. Fig. 3.2 Suggest one conclusion that the student can make from these results. [1] (c) The student adds the solids A, B and C to solid ammonium chloride. He warms the mixture. Fig. 3.3 shows the results. solid A with solid ammonium chloride solid B with solid ammonium chloride solid C with solid ammonium chloride A gas is given off. The gas has a strong smell. No apparent reaction. No apparent reaction. Fig. 3.3

9 © UCLES 2006 0652/06/O/N/06 [Turn over For Examiner's Use (i) The student thinks that the strong smelling gas is ammonia. Suggest a test to confirm the presence of ammonia and give the result you expect. [2] (ii) What does this tell you about solid A? [1] (d) The student adds aqueous ammonia to solutions of A, B and C, until no further reaction is seen. Fig. 3.4 shows the results. solution of A with aqueous ammonia. solution of B with aqueous ammonia solution of C with aqueous ammonia. No apparent reaction. A clear solution is left. There is a rise in temperature. A white precipitate forms. It dissolves when excess ammonia is added. Fig. 3.4 (i) Name the kind of reaction that takes place between aqueous ammonia and the solution of B. [1] (ii) Suggest the identity of the white precipitate formed when solution C reacts with aqueous ammonia. [1] (e) The student decides which of the solids, A, B and C is a salt. He thinks that the salt is a sulphate. Describe a test that he can use to confirm the presence of a sulphate in the solution of the salt and give the result that you expect. test result [2]

11 © UCLES 2006 0652/06/O/N/06 [Turn over For Examiner's Use 4 A student does an experiment to find out how long it takes for 100 cm3 of a gas to flow out of a small hole. He uses a syringe fitted with a tap and a tube ending in a very small hole. The gas will flow out of the hole as the piston of the syringe descends. The apparatus is shown in Fig. 4.1. 100 cm3 W weight piston moves down syringe containing gas very small hole gas out Fig. 4.1 tap T gas in under pressure The student follows the list of instructions below. One of the instruction lines is missing. (a) Study Fig. 4.1 and the instructions, then fill in the missing line. List of Instructions • Make sure the stopclock is set at 0 seconds. • Open tap T to allow gas to enter the syringe • When the syringe contains about 110 cm3 of gas, close tap T. • • When the syringe is empty, stop the clock. • Record the time taken in Fig. 4.2. [1]

12 © UCLES 2006 0652/06/O/N/06 For Examiner's Use (b) The student performed the experiment using four different gases. Two of his results are shown in Fig. 4.2. gas contained in syringe oxygen O2 hydrogen H2 methane CH4 chlorine Cl2 time for 100 cm3 of gas to flow out/s 30 7 relative molecular mass of the gas 32 2 Fig. 4.2 The stopclock dials in Fig. 4.3 show the times taken by 100 cm3 of each of the other gases to flow out of the syringe. Read the dials and record the times in Fig. 4.2. [2] 0 time for methane Fig. 4.3 45 15 30 s 0 time for chlorine 45 15 30 s (c) Calculate the relative molecular masses of methane and chlorine. Record the answers in Fig. 4.2. [Ar: H, 1; C, 12; Cl, 35.5] [1] (d) Suggest a way of making the hydrogen to use in the experiment. [1]

13 © UCLES 2006 0652/06/O/N/06 [Turn over For Examiner's Use The teacher asks the student to explain why the times for the gases to flow out were all different. He makes four suggestions. A Gases that have larger molecules flow more slowly. B Gas molecules with greater mass flow more slowly. C Attraction between molecules causes gases to flow more slowly. D Gravity attracts heavier molecules so they flow out more quickly. (e) (i) Use your knowledge of the kinetic theory of gases to help you to choose the letter of the best explanation for the observations made in this experiment. The best explanation is suggestion [1] (ii) Choose data from Fig. 4.2 and use it to support the explanation you have chosen in (i). [2] (f) Suggest one safety precaution that should be taken when performing the experiments described in this question. Give a reason for the safety precaution. safety precaution reason [2]

14 © UCLES 2006 0652/06/O/N/06 For Examiner's Use 5 When air is heated, it expands. An experiment was done to investigate this expansion. Air was drawn into a 100 cm3 glass syringe and then the nozzle was sealed. The syringe was placed in a tall beaker of cold water. stirrer thermometer water heat 100 cm3 Fig. 5.1 The water was slowly warmed and gently stirred. At intervals, a thermometer was used to find the temperature of the water. The temperature reading and the volume of air in the syringe were recorded in Fig. 5.2. reading number 1 2 3 4 5 temperature / oC 2 25 50 volume / cm3 53 59 64 Fig. 5.2

15 © UCLES 2006 0652/06/O/N/06 [Turn over For Examiner's Use (a) The scales of the thermometer and the syringe for the two missing readings are shown in Fig. 5.3. Read the temperatures and the volumes and record the values in Fig. 5.2. [4] 80 75 70 65 60 reading 4 100 95 90 85 80 reading 5 thermometer syringe 80 70 60 50 cm3 90 80 70 60 cm3 Fig. 5.3

16 © UCLES 2006 0652/06/O/N/06 For Examiner's Use (b) On the grid provided, plot the volume of air (vertical axis) against the temperature. Draw the best fit straight line. [3] (c) Use your knowledge of the behaviour of gas molecules to explain why the air in the syringe expanded when it was heated. [2]

17 © UCLES 2006 0652/06/O/N/06 [Turn over For Examiner's Use (d) In a different experiment, the sealed syringe containing a hydrocarbon gas was placed in water at room temperature. Then the beaker of water was surrounded by ice at 0 oC. The graph shows how the volume of the gas changed as the temperature drops towards 0 °C. 60 40 20 0 0 10 20 30 40 temperature / °C volume / cm3 temperature at the start of the experiment Fig. 5.4 Explain why there was a sudden large decrease in the volume of the gas. [1]

18 © UCLES 2006 0652/06/O/N/06 For Examiner's Use 6 The teacher gave the class four liquids labelled A, B, C and D. She asked them to identify the liquids by doing two experiments and using a key, shown in Fig. 6.2. First experiment. Finding the density of the liquids. • A 50 cm3 measuring cylinder was placed on a balance. • The balance was adjusted so that it read 0.0 g with the measuring cylinder on the pan. • 50 cm3 of each liquid was placed in the cylinder. Fig. 6.1 shows the balance window for each liquid in turn. liquid A g 53 52 liquid B g 49 48 liquid C g 48 47 liquid D g Fig. 6.1 (a) Read the balance windows and record the masses in the spaces provided. mass of 50 cm3 of liquid A g mass of 50 cm3 of liquid B g mass of 50 cm3 of liquid C g mass of 50 cm3 of liquid D g [4]

19 © UCLES 2006 0652/06/O/N/06 [Turn over For Examiner's Use (b) Use the data from (a) to help you to write the letters of the four liquids in the correct spaces in boxes 1, 2 and 3 of the key, Fig. 6.2. Do not attempt to complete boxes 4 and 5 until you answer part (c). [2] Key for identifying four liquids, A, B, C and D liquid has a density less than 1 g / cm3 liquid has a density of 1 g / cm3 liquid has a density greater than 1 g / cm3 1. liquids … and … 2. liquid … 4. liquid … 5. liquid … 3. liquid … liquid does not mix with water liquid mixes with water in all proportions WATER SODIUM CHLORIDE (SALT) SOLUTION A HYDROCARBON ALCOHOL Fig. 6.2 Second experiment. Mixing the liquids with water. Fig. 6.3. shows the effect of placing 10 cm3 of each of the liquids with 10 cm3 of water in a test-tube. (c) Use information from Fig. 6.3 to help you to complete boxes 4 and 5 in the key, Fig. 6.2. [1] liquid A + water liquid B + water liquid C + water liquid D + water Fig. 6.3 (d) Suggest a different test you can carry out to distinguish between the alcohol and the hydrocarbon. [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 2006 0652/06/O/N/06 For Examiner's Use (e) Describe a chemical test you can carry out to confirm the identity of the salt solution. [2]

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2006 question paper 0652 PHYSICAL SCIENCE 0652/06 Paper 6 (Alternative to Practical), maximum raw mark 60 This mark scheme is published as an aid to teachers and students, 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. The grade thresholds for various grades are published in the report on the examination for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses. • CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2006 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 - OCT/NOV 2006 0652 6 © UCLES 2006 1 (a) (i) carbon dioxide or CO2 [1] (ii) lime-water, goes cloudy/white (precipitate) if an incorrect gas is named in (a)(i) a correct test for that gas must be given [1] (b) (i) 35.8 g, 39.2 g (no tolerance)(if given in wrong order 1 mark only) [2] (ii) 3.4g (ecf) [1] (c) bubbling stops OWTTE (reject, all the solid has dissolved : any answers based on use of an indicator) [1] (d) (i) 26.2 g, 1.7 g (no tolerance) (if written in the wrong spaces 1 mark only) [2] (ii) 24.5 g (ecf) [1] (e) 24.5 / 10 = 2.45g calcium carbonate (ecf) (1) [1] Total 10 marks 2 (a) 12 mm, 63 mm: 17 mm, 60 mm (+/- 1 mm) [4] (b) (i) axes correct & labelled (1) all points plotted accurately (+/- 1 mm)(1) straight line drawn cutting the y-axis (1) (no marks for graph of y (or x) against reading number) [3] (ii) 72 mm +/- 2 mm (answer checked with candidate’s graph) (no marks for answers given in centimetres) [1] (iii) line correctly drawn (+/- 1 mm) and point M labelled (ecf) [1] (c) the weight of the card is not acting at point N/ N is not the centre of mass/ one side of the card is heavier than the other OWTTE [1] Total 10 marks

Page 3 Mark Scheme Syllabus Paper IGCSE - OCT/NOV 2006 0652 6 © UCLES 2006 3 (a) sodium carbonate ammonium chloride aqueous ammonia acid √ √ base √ salt √ √ 4 (or 5) correct (2) 2 or 3 correct (1) 1 or 0 (0) [2] (note that if more than 4 ticks are shown, the number of wrong answers is subtracted from the number of correct answers) (b) solid B is an acid/solid C contains a metal/solid A is not an acid/solid B produces carbon dioxide/other suitable conclusion [1] (c) (i) (moist) (red) litmus (Universal Indicator)(paper) (1) is turned blue(purple)/other suitable test for ammonia (1) [2] (ii) solid A is a base (alkali) [1] (d) (i) neutralisation/ammonia is neutralised/exothermic/salt formation [1] (ii) metal (zinc) hydroxide (zinc need not be named for the mark) (accept aluminium)(reject metals giving a coloured hydroxide) [1] (e) (i) add barium chloride (nitrate) (and hydrochloric (nitric) acid) (the addition of acid need not be mentioned) [1] (ii) white solid/white precipitate seen [1] Total 10 marks

Page 4 Mark Scheme Syllabus Paper IGCSE - OCT/NOV 2006 0652 6 © UCLES 2006 4 (a) when the syringe reads a measured volume (100cm3), start the clock (both statements are required for the mark) [1] (b) 18, 43 cm3 (no tolerance) [2] (c) CH4 = 16, Cl2 = 71 (both correct) [1] (d) suitable named metal + hydrochloric or sulphuric acid /electrolysis of suitable named electrolyte (reject "metal + acid") [1] (e) (i) B [1] (ii) the lower the rmm the faster the flow or the higher the rmm the slower the flow (1) names and/or figures from the table used (1) [2] (f) no naked flame (1) hydrogen (methane) is flammable/explodes (1) or ventilate laboratory/use fume cupboard/do not inhale chlorine (1) chlorine is poisonous (1) reason must match safety precaution do not award mark for use of laboratory clothing, goggles, or other precaution not directly connected with the experiment [2] Total 10 marks 5 (a) 73, 97°C, (2) 67, 73 cm3 (2) no tolerance [4] (b) sensible scale chosen and axes labelled (1) points plotted (1) +/- 1°C and 1cm 3 best straight line drawn (1) [3] (c) when heated molecules have more energy (1) molecules collide (with walls) (bounce) (or with each other) with greater force (reject "vibrate")(1) collisions (between molecules) occur more often (1) volume or pressure is raised (1) any 2 points [2] (d) gas changes state/becomes liquid/solid (on cooling) [1] Total 10 marks

Page 5 Mark Scheme Syllabus Paper IGCSE - OCT/NOV 2006 0652 6 © UCLES 2006 6 (a) 52.5, 48.8, 47.3, 50.0 (must say 50.0) no tolerance [4] (b) B and C (1), D, A (in correct order) (1) [2] (c) C, B (in correct order) ecf from (b) [1] (d) hydrocarbon will burn in air with a yellow (smoky) flame alcohol burns with a blue flame alcohol reacts with (conc) sulphuric acid alcohol will form an ester alcohol will react with sodium/other suitable suggestion (any 1) [1] (e) add silver nitrate (solution) (1), white precipitate (1) OR yellow (orange) (1) flame test (1) [2] Total 10 marks