Cambridge IGCSE Science - Combined 0653 — 2013 Oct/Nov Paper 5 · Variant 1

This document consists of 10 printed pages and 2 blank pages. IB13 11_0653_51/3RP © UCLES 2013 [Turn over *4715197697* For Examiner's Use 1 2 3 Total UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/51 Paper 5 Practical Test October/November 2013 1 hour 30 minutes Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions 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 pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units. Chemistry practical notes for this paper are printed on page 12. 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 2013 0653/51/O/N/13 For Examiner's Use 1 You are going to carry out tests on two experiments to investigate the digestion of starch in the alimentary canal. One of these experiments is set up for you and you will set up the other yourself. When it has been set up, you will then carry out the tests and answer the questions. 1st experiment An experiment has been set up for you as in Fig. 1.1. This is a model of the digestion and absorption of starch in the alimentary canal. glass rod visking tubing water starch and amylase Fig. 1.1 The piece of “visking tubing” represents the alimentary canal. It was set up one hour ago, with a mixture of starch and amylase inside it. The visking tubing forms a selectively permeable membrane – it allows smaller molecules to pass through it, but not larger molecules. Setting up the 2nd experiment • Label two test-tubes P and Q. • Stir the starch solution provided and then transfer some of it into the two test-tubes, so that each test-tube is about one-third full. • Add about the same amount of amylase solution to test-tube P, and mix the contents with a clean glass rod. • Add an equivalent volume of distilled water to test-tube Q and mix the contents with a clean glass rod. • Keep test-tubes P and Q for later.

3 © UCLES 2013 0653/51/O/N/13 [Turn over For Examiner's Use (a) Tests and questions about the 1st experiment (i) • Use a pipette to remove two samples of water from the beaker in the apparatus that was set up for you. • Place each sample in a clean test-tube. You will need 1-2 cm depth of liquid in each test-tube. • Label these test-tubes R1 and R2. • Test the liquid in test-tube R1 for starch by adding iodine solution. Record the results in Table 1.1 and in the last column say whether or not starch is present. • Test the liquid in test-tube R2 for reducing sugar by adding Benedict’s solution and placing the test-tube in a hot water bath for about three minutes. Record the result in Table 1.1 and in the last column say whether or not sugar is present. Table 1.1 test-tube result conclusion R1 R2 [3] (ii) Explain what the results and conclusions from test-tubes R1 and R2 in Table 1.1 suggest about the ability of sugar molecules to pass through the visking tubing. [1]

4 © UCLES 2013 0653/51/O/N/13 For Examiner's Use (b) Tests and questions about the 2nd experiment (i) • Divide the liquid in test-tube P approximately equally between two test-tubes, and label these P1 and P2. • Test the liquid in test-tube P1 for starch, and the liquid in P2 for reducing sugar, using the same method as in part (a). Record your results in Table 1.2 and in the last column say whether or not starch or sugar is present. • In the same way, divide the liquid in test-tube Q approximately equally between two test-tubes, Q1 and Q2. • Test the liquid in test-tube Q1 for starch and the liquid in Q2 for reducing sugar. Complete the remainder of Table 1.2. Table 1.2 test-tube result conclusion P1 P2 Q1 Q2 [4] (ii) Amylase digests starch. Explain what the results and conclusions in Table 1.2 tell you about the effect of amylase on starch solution. [1] (c) With reference to the results of these experiments, explain why starch needs to be digested in the alimentary canal. [1]

5 © UCLES 2013 0653/51/O/N/13 [Turn over Please turn over for Question 2.

6 © UCLES 2013 0653/51/O/N/13 For Examiner's Use 2 You will follow a series of instructions to investigate the formation of an image by a converging lens using the experimental set-up shown in Fig. 2.1. u v screen illuminated object converging lens Fig. 2.1 A converging lens is thicker in the middle and refracts light so that an image is formed on a screen some distance away. You will move the lens to vary the object distance u and move the screen to vary the image distance v. (a) (i) • Place the lens a distance u = 35.0 cm from the illuminated object (the triangular hole in the card). • Switch on the lamp so that an image of the illuminated object can be seen on the screen. • Adjust the position of the screen by moving it backwards and forwards along the bench, until a sharp image of the illuminated object is formed on the screen. • Measure, to the nearest 0.1 cm, the distance v from the screen to the lens. • Record the distance v in Table 2.1. [1] Table 2.1 object distance u / cm image distance v / cm image distance / object distance = v / u 35.0 30.0 25.0 20.0 (ii) Repeat the procedure described in (i) for values of u = 30.0 cm, 25.0 cm, and 20.0 cm. [2] (iii) Complete the remaining boxes in the table by filling in the values of the ratio v / u, the ratio of image distance to object distance. [1]

7 © UCLES 2013 0653/51/O/N/13 [Turn over For Examiner's Use (b) (i) On the grid provided, plot a graph of v against v / u. Draw the best fit straight line. [3] v / cm v / u (ii) Calculate the gradient of your line. Show all working and indicate on your graph the values you chose to enable the gradient to be calculated. gradient = [2] (c) This experiment is unsuitable for values of u close to 15.0 cm. Use your observations from the experiment to suggest why this is so. [1]

8 © UCLES 2013 0653/51/O/N/13 For Examiner's Use 3 You are going to carry out a series of tests to identify compound X. You may wish to refer to the Chemistry Practical Notes on page 12 to help you with your interpretations of the results of the tests. (a) Heat the hard glass test-tube containing X until there is no further visible change. Record your observation below and leave this test-tube to cool. You will be using the contents of this test-tube in (c). observation [1] (b) (i) Place two spatula loads of X into a test-tube and add about 4 cm3 of dilute hydrochloric acid. Pass the gas produced through limewater in another test-tube. Keep the mixture of X and acid for (b)(ii). Record your observations, identify the gas produced, and the anion in X. observations name of gas name of anion [4] (ii) Transfer the contents of the test-tube from (b)(i) to the small beaker and add excess dilute sodium hydroxide. Record your observations and suggest the name of the metal cation in X. observations name of metal cation [2]

9 © UCLES 2013 0653/51/O/N/13 For Examiner's Use (c) The hard glass test-tube and its contents from (a) should now have cooled. Add about 4 cm3 dilute nitric acid, stir and wait for 2 minutes. Then filter the mixture into a test-tube. To the test-tube containing the filtrate, slowly add ammonia solution until there is no further change. Record your observations. observations [2] (d) Using your observations for (a), (b) and (c), identify compound X. compound X is [1]

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12 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 2013 0653/51/O/N/13 CHEMISTRY PRACTICAL NOTES Test for anions anion test test result carbonate (CO3 2-) add dilute acid effervescence, carbon dioxide produced chloride (Cl -) [in solution] acidify with dilute nitric acid, then add aqueous silver nitrate white ppt. nitrate (NO3 -) [in solution] add aqueous sodium hydroxide then aluminium foil; warm carefully ammonia produced sulfate (SO4 2-) [in solution] acidify then add aqueous barium chloride or aqueous barium nitrate white ppt. Test for aqueous cations cation effect of aqueous sodium hydroxide effect of aqueous ammonia ammonium (NH4 +) ammonia produced on warming - copper(II) (Cu2+) light blue ppt., insoluble in excess light blue ppt., soluble in excess giving a dark blue solution iron(II) (Fe2+) green ppt., insoluble in excess green ppt., insoluble in excess iron(III) (Fe3+) red-brown ppt., insoluble in excess red-brown ppt., insoluble in excess zinc (Zn2+) white ppt., soluble in excess giving a colourless solution white ppt., soluble in excess giving a colourless solution Test for gases gas test and test results ammonia (NH3) turns damp red litmus paper blue carbon dioxide (CO2) turns limewater milky chlorine (Cl2) bleaches damp litmus paper hydrogen (H2) “pops” with a lighted splint oxygen (O2) relights a glowing splint

CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2013 series 0653 COMBINED SCIENCE 0653/51 Paper 5 (Practical), maximum raw mark 45 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 should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the October/November 2013 series for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level components and some Ordinary Level components. www.XtremePapers.com

Page 2 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0653 51 © Cambridge International Examinations 2013 1 (a) (i) test-tube result conclusion R1 orange / brown / red / yellow / no change ; no starch / not present / no AND R2 orange / red / yellow / green / brown (ppt) ; sugar / present / yes ; [3] Both conclusions required and both must match correct observations for third mark. (ii) (sugar molecules) can pass through (visking tubing because found in beaker) ; [1] (b) (i) test-tube result conclusion P1 orange / brown / red / yellow / no change AND... no starch / not present / no ; P2 orange / red / yellow / green / brown (ppt) AND... sugar / present / yes ; Q1 blue-black / black / blue AND... starch / present / yes ; Q2 blue / no change AND... no sugar / not present / no ; [4] (ii) amylase converts starch to sugar ; [1] (c) because (starch) molecules are too big / so that it can be absorbed / can pass through the gut wall / sugar can pass through wall / only sugar absorbed / sugar molecules are small enough ; [1] [Total: 10]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0653 51 © Cambridge International Examinations 2013 2 (a) (i) all recorded v values are to the nearest 0.1 cm ; [1] (ii) at least three v values present ; v values increasing down the table for all recorded readings ; [2] (iii) v / u values correct to at least 2 sig fig ; [1] (b) (i) suitable choice of scales (points should be in an area at least 6 cm × 6 cm) ; at least 3 points plotted correctly to half a small square ; good best fit straight line judgement ; [3] (ii) indication on graph of how data obtained AND use of at least half of line drawn ; correct calculation to at least 2 sig fig using data from the graph ; [2] (c) image will not fit on the screen / is too far away from the object / not formed / not sharp; (allow any reasonable interpretation of results from graph) [1] [Total: 10]

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0653 51 © Cambridge International Examinations 2013 3 (a) (green to) black / brown-black (powder) ; [1] (b) (i) observations: green / green-blue (solution) ; limewater turns milky / chalky / white ppt (not cloudy) ; name of gas = carbon dioxide / CO2 ; (dependant on limewater or effervescence observation) name of anion = carbonate / CO3 2– ; [4] (ii) observations: blue ppt ; name of metal cation: copper / Cu2+ (dependant on ‘blue’ observation) ; [2] (c) observations: blue ppt (not dark blue ppt) ; deep blue solution / dark blue solution ; [2] (d) copper carbonate / copper(II) carbonate / CuCO3 ; [1] [Total: 10]