Cambridge IGCSE Science - Combined 0653 — 2013 Oct/Nov Paper 5 · Variant 2

This document consists of 12 printed pages. IB13 11_0653_52/3RP © UCLES 2013 [Turn over *3007014303* For Examiner's Use 1 2 3 Total UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/52 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 0653/52/O/N/13 For Examiner's Use 1 You are provided with two Petri dishes, A and B, each set up as shown in Fig. 1.1. The dishes contain a starch-agar mixture. This is a gel to which starch solution has been added. This experiment uses barley grains that have been germinated. Some of the barley grains have been killed by being placed in boiling water. Barley grains have been placed on the starch-agar mixture in each of the two dishes, and left for a few days. • In dish A, the barley grains are living. • In dish B, the barley grains are dead. Petri dish starch-agar gel barley grains Fig. 1.1 (a) You are going to look for evidence of starch-digesting enzymes being produced by the barley grains. (i) Remove the lids from Petri dishes A and B, and make drawings in Table 1.1 to show the positions of the barley grains in each dish. Table 1.1 dish A dish B [1]

3 © UCLES 2013 0653/52/O/N/13 [Turn over For Examiner's Use (ii) Remove the barley grains from each of the dishes A and B. Test the gel in the Petri dishes for starch, by covering the gel with iodine solution, and then waiting for a minute to let any colour changes happen. Pour away the excess iodine solution, and then place the dishes onto two white tiles. Make drawings in Table 1.2 to show the distribution of the colours in each dish. Label the colours. Table 1.2 dish A dish B [2] (iii) Compare the two drawings that you made of dish A. [1] (iv) Write a conclusion based on this comparison. [1] (v) In dish B, dead barley grains were used. What is the purpose of dish B? [1] (b) Explain why several barley grains were used in each Petri dish, rather than just one. [1]

4 © UCLES 2013 0653/52/O/N/13 For Examiner's Use (c) Suggest how the results of the iodine experiment would have been different if the Petri dishes had been kept at a lower temperature. [1] (d) Outline an experiment that you could do to compare the effect on starch-agar gel of two different varieties of seeds. [2]

5 © UCLES 2013 0653/52/O/N/13 [Turn over Please turn over for Question 2.

6 © UCLES 2013 0653/52/O/N/13 For Examiner's Use 2 You are going to find the mass of a metre rule by a balancing method. (a) (i) Place the knife edge directly under the 55.0 cm mark of the metre rule so that the distance d = 55.0 cm. Place the load M on the metre rule and adjust its position carefully until the rule is just balanced, as shown in Fig. 2.1. load M knife edge bench d = 55.0 cm x Fig. 2.1 Measure the distance x from the centre of the load to the knife edge. Record this distance in Table 2.1. [1] Table 2.1 distance d / cm x / cm 55.0 60.0 65.0 70.0 75.0 (ii) Describe how you located the position of the centre of the load M before you measured the distance x. [1] (iii) Repeat the procedure to balance the load when the knife edge is placed at distances d of 60.0 cm, 65.0 cm, 70.0 cm and 75.0 cm from the end of the metre rule. Record the corresponding distances x in Table 2.1. [2] (b) (i) On the grid provided on page 7, plot a graph of d against x. You do not need to start both axes from the origin. Draw the best fit straight line. [3]

7 © UCLES 2013 0653/52/O/N/13 [Turn over d / cm x / cm (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]

8 © UCLES 2013 0653/52/O/N/13 For Examiner's Use (c) The gradient of your line is related to the mass m in grams of the metre rule by the equation m = gradient 150 Determine the mass of the metre rule. m = g [1]

9 © UCLES 2013 0653/52/O/N/13 [Turn over Please turn over for Question 3.

10 © UCLES 2013 0653/52/O/N/13 For Examiner's Use 3 Solution X is a mixture containing two cations and two anions. You are going to carry out the tests below to help you identify these ions. You may wish to use the Chemistry Practical Notes on page 12 to help you interpret the results of your tests. (a) (i) Place about 2 cm3 of solution X in a test-tube and add an equal volume of dilute nitric acid. Retain this mixture for (a)(ii) and (a)(iii). Record in Table 3.1 your observations. (ii) To half of the mixture from (a)(i) add an equal volume of barium chloride solution. Record in Table 3.1 your observations and conclusions about any ions present. (iii) To the other half of the mixture from (a)(i) add an equal volume of silver nitrate solution. Record in Table 3.1 your observations and conclusions about any ions present. Table 3.1 test observations conclusions (i) dilute nitric acid [1] (ii) barium chloride solution [1] [1] (iii) silver nitrate solution [1] [1]

11 © UCLES 2013 0653/52/O/N/13 For Examiner's Use (b) Place about 1 cm3 of solution X in a test-tube and add ammonia solution until the test-tube is three-quarters full. Filter the mixture. Record in Table 3.2 your observations and conclusions about any ions present. Table 3.2 test observations conclusions ammonia solution [2] [2] (c) Use the observations and conclusions that you have recorded in Tables 3.1 and 3.2 to suggest names for the compounds that might be contained in mixture X. compounds in X [1]

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 0653/52/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 0653/52 Paper 5 (Practical Test), maximum raw mark 30 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 52 1 (a) (i) barley grains drawn in both dishes ; [1] (ii) drawings of both dishes ; dish A shows brown / orange / yellow and blue / black areas labelled AND no brown in dish B ; [2] (iii) brown / orange / yellow colour around where the barley grains were ; (allow no starch where grains were) [1] (iv) (enzyme from the) barley grains breaking down / digesting the starch ; (allow area below grains no longer contains starch) [1] (v) control / shows that breakdown depends on living barley grains ; [1] (b) improved reliability / because one seed might not be active / owtte ; [1] (c) smaller brown areas / more starch ; [1] (d) use different varieties on different dishes or on different parts of the same dish ; keep (named) conditions constant ; compare diameters or sizes of brown areas ; [max 2] [Total: 10]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2012 0653 52 2 (a) (i) reading for x when d = 55 cm ; [1] (ii) note reading on either side of mass and find the mean value ; [1] (iii) complete set of x values ; x values increasing down the table ; [2] (b) (i) suitable choice of scales (points use at least 8 cm × 8 cm of grid) ; at least 4 points correct to half a small square ; good best fit line judgement ; [3] (ii) indication on graph of how data obtained AND at least half of line used ; correct calculation from triangle method using data from graph (at least 2 significant figures) ; [2] (c) correct calculation of m (from candidate’s gradient value) 2 / 3 significant figures AND correct rounding required ; [1] [Total: 10]

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2012 0653 52 3 test observation conclusion (a) (i) dilute nitric acid no reaction / nothing / paler solution ; (ii) barium chloride solution ppt of stated colour ; sulfate / SO4 2– ; (iii) silver nitrate solution white ppt ; chloride / Cl – ; [5] (b) test observation conclusion ammonia solution brown / orange / red-brown / yellow-brown AND ppt / residue ; dark blue filtrate ; iron(III) / Fe3+ ; copper(II) / Cu2+ ; [4] (c) iron(III) chloride AND copper(II) sulfate / iron(III) sulfate AND copper(II) chloride ; (allow any three or all four compounds but not a list of the ions) [1] [Total: 10]