Cambridge IGCSE Science - Combined 0653 — 2006 Oct/Nov Paper 6 · Variant 1

Centre Number Candidate Number Name UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/06 CO-ORDINATED SCIENCES 0654/06 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, graphs or rough working. 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 18 printed pages and 2 blank pages. IB06 11_0653_06/3RP  UCLES 2006 [Turn over www.XtremePapers.com

2 © UCLES 2006 0653/06/O/N/06 For Examiner's Use 1 Mammals have fur to insulate them against heat loss. A student did an experiment to find out what difference it made to an animal’s heat loss with both dry and wet body covering. The test-tube of hot water represented the mammal and the cotton wool represented the fur. The apparatus is shown in Fig. 1.1. tube A tube B elastic band test-tube rack cotton wool Fig. 1.1 Method • The student wrapped cotton wool around two identical test-tubes and placed them in a rack. • He wet the cotton wool of tube B with water then replaced it in the rack. • He poured the same amount of boiling water into both tubes leaving a space at the top. • He placed thermometers into the test-tubes. • He then took a reading from both thermometers at the same time and recorded the temperatures in Fig. 1.2. • He continued to take readings from both thermometers and recorded them every minute for 5 minutes. time / minutes temperature of tube A / oC temperature of tube B / oC 0 77 77 1 74 55 2 70 49 3 46 4 64 5 62 42 Fig. 1.2 (a) Read the thermometers in Fig. 1.3 below to complete Fig. 1.2. [2] 80 70 60 50 °C tube A 60 50 40 30 °C tube B Fig. 1.3

3 © UCLES 2006 0653/06/O/N/06 [Turn over For Examiner's Use (b) (i) Plot temperature (vertical axis) against time for tube A. Draw a smooth curve and label it tube A. On the same axes plot the results for tube B. Draw a smooth curve and label it tube B. [4] (ii) Which test-tube, A or B, cooled faster? Explain your answer. [3] (c) List three ways in which the student ensured it was a fair test. 1. 2. 3. [3] (d) The skin of mammals produces oil that coats the fur. This makes it water-resistant, so that rain will run off the fur, preventing it from becoming wet. Suggest how washing a mammal’s fur with strong detergent may interfere with its ability to retain heat. [2]

4 © UCLES 2006 0653/06/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 0653/06/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 © UCLES 2006 0653/06/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 0653/06/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) Explain why the card would not balance on point N. [1]

8 © UCLES 2006 0653/06/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 0653/06/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 0653/06/O/N/06 [Turn over For Examiner's Use 4 The photographs, Fig. 4.1, are of sections through two different fruits, A and B. A B Fig. 4.1 (a) Make a drawing of the section through fruit A in the space provided below. [2] (b) (i) The seeds from both of these fruits are dispersed in a similar way. Describe how they are dispersed. [2] (ii) Describe one feature, visible in the photographs, that adapts the fruits to dispersal in this way and explain why it is successful. [2]

12 © UCLES 2006 0653/06/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

13 © UCLES 2006 0653/06/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

14 © UCLES 2006 0653/06/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]

15 © UCLES 2006 0653/06/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]

16 © UCLES 2006 0653/06/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]

17 © UCLES 2006 0653/06/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]

18 © UCLES 2006 0653/06/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]

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 University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. 0653/06/O/N/06 BLANK PAGE

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2006 question paper 0653 and 0654 COMBINED SCIENCE AND CO-ORDINATED SCIENCES 0653/06 and 0654/06 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 0653 and 0654 06 © UCLES 2006 1 (a) 67, 44 +/- 0.5o [2] (b) (i) suitable scale chosen and axes labelled correctly (1) points plotted correctly (2) (allow 1 mistake in each curve) suitable curves drawn (not joined by straight lines) (1) [4] (ii) tube B (1) air trapped round A (1) cotton wool is a poor conductor of heat (1) B is wet therefore heat is lost (faster) (1) [3] (c) identical test-tubes/same volume of water/same temperature /thermometers read at same times/same surroundings for the tubes (any three points) [3] (d) oil is removed so water wets fur (1) AND therefore heat is lost (1) OR (air not trapped) no insulation (1) [2] [Total: 14] 2 (a) 12 mm, 63 mm: 17 mm, 60 mm (+/- 1 mm) [4] (b) (i) axes correct and labelled (1) points plotted (+/- 1 mm) (1) straight line drawn cutting y-axis (1) [3] (ii) 72 mm +/- 2 mm (or answer checked with candidate’s graph) (allow answer derived from any line cutting y-axis on graph) no marks for answers in cm [1] (iii) line correctly drawn (ecf) and point M labelled [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]

Page 3 Mark Scheme Syllabus Paper IGCSE - OCT/NOV 2006 0653 and 0654 06 © 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 correct (0) (score is decreased by excess of ticks greater than 5) [2] (b) solid B is an acid/carbon dioxide is given off by reaction with B/solid C contains a metal/A is not an acid/other suitable conclusion [1] (c) (i) litmus (Universal Indicator)(paper) (1) is turned from red to blue(purple) (1) other suitable test for ammonia [2] (ii) solid A is a base (alkali) [1] (d) (i) neutralisation/ammonia is neutralised/exothermic [1] (ii) (zinc or aluminium)(metal) hydroxide(essential) (metal need not be named for the mark) [1] (e) (i) add barium chloride (nitrate) (or lead nitrate) [1] (ii) white solid/white precipitate seen [1] [Total: 10] 4 (a) Clear outline of shapes and internal structure (1) seeds clearly shown (1) [2] (b) (i) eaten by animals (1) not digested/pass through gut and deposited in faeces (1) (accept other descriptions) [2] (ii) animals are attracted (1) by juicy(fleshy) fruit (NOT colour) (allow 1 mark for mention of large number of seeds) (mark parts (b)(i) and (ii) together) [2] [Total: 6]

Page 4 Mark Scheme Syllabus Paper IGCSE - OCT/NOV 2006 0653 and 0654 06 © UCLES 2006 5 (a) 73, 97o C, (2) 67, 73 cm3 (2) no tolerance [4] (b) sensible scale chosen and axes labelled (1) points plotted (1) (+/- 1oC and 1 cm) straight line drawn (1) [3] (c) when heated molecules have more energy (1) molecules collide with walls (with each other) OWTTE with greater force (1) (reject "vibrate") pressure (volume) is raised (1) any 2 points [2] (do not accept "molecules move faster therefore occupy more space") (d) gas becomes liquid/gas condenses/sublimation/solid formed/change of state/phase change (do not accept "molecules are frozen") [1] [Total: 10] 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 part (a) [1] (d) hydrocarbon will burn in air with a yellow(smoky) flame alcohol burns with a blue flame alcohol will react with conc. sulphuric acid alcohol will form an ester other suitable suggestion (any 1) [1] (e) add silver nitrate solution (1), gives a white precipitate (1) OR yellow (orange) (1) flame test (1) [2] [Total: 10]