Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2013 Oct/Nov Paper 5 · Variant 3

This document consists of 12 printed pages. IB13 11_0654_53/FP © UCLES 2013 [Turn over *6079430015* For Examiner's Use 1 2 3 Total UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education CO-ORDINATED SCIENCES 0654/53 Paper 5 Practical Test October/November 2013 2 hours 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.

2 © UCLES 2013 0654/53/O/N/13 For Examiner's Use 1 You are provided with four Petri dishes, A, B, C and D, 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 four dishes, and left for a few days. • In dishes A and B, the barley grains are living. • In dishes C and D, 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 C, and make drawings in Table 1.1 to show the positions of the barley grains in each dish. Table 1.1 dish A dish C [1]

3 © UCLES 2013 0654/53/O/N/13 [Turn over For Examiner's Use (ii) Remove the barley grains from each of the dishes A and C. 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 C [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 C, dead barley grains were used. What is the purpose of dish C? [1]

4 © UCLES 2013 0654/53/O/N/13 For Examiner's Use (b) Now test the gel in dishes B and D for the presence of reducing sugar. • Label two test-tubes, B and D. • From dish B, use a knife or a spatula to take a small piece of starch-agar gel from underneath each of the groups of barley grains. Put these two pieces of gel into the test-tube labelled B. • Repeat the procedure for Petri dish D, putting your pieces of starch-agar gel into the test-tube labelled D. • Add five drops of Benedict’s solution to each test-tube. • Place both test-tubes into a hot water bath for three minutes. (i) Record your results in Table 1.3. Table 1.3 test-tube B test-tube D colour of Benedict’s solution before heating colour of Benedict’s solution after heating [2] (ii) Explain the results you obtained in tube B, tube D. [4] (c) Explain why several barley grains were used in each Petri dish, rather than just one. [1]

5 © UCLES 2013 0654/53/O/N/13 [Turn over For Examiner's Use (d) Suggest how the results of the iodine experiment would have been different if (i) the barley grains in the Petri dishes had been left for a longer period of time, [1] (ii) the Petri dishes had been kept at a lower temperature. [1]

6 © UCLES 2013 0654/53/O/N/13 For Examiner's Use 2 You are going to find the mass and volume of a metre rule, and hence determine the density of the material from which the rule is made. (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 (vertical axis) against x (horizontal axis). You do not need to start both axes from the origin. Draw the best fit straight line. [4]

7 © UCLES 2013 0654/53/O/N/13 [Turn over For Examiner's Use (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 0654/53/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] (d) w t width w thickness t Fig. 2.2 (i) Measure the thickness t and the width w of the rule. Record your answers in the spaces below. t = cm w = cm [2] (ii) Calculate the density of the material from which the rule is made using the formula density = t w m × × 100 density = g / cm3 [2]

9 © UCLES 2013 0654/53/O/N/13 [Turn over Please turn over for Question 3.

10 © UCLES 2013 0654/53/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. (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 and conclusion about any ions present. (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 conclusion 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 conclusion about any ions present. Table 3.1 test observations conclusion (i) dilute nitric acid [1] [1] (ii) barium chloride solution [1] [1] (iii) silver nitrate solution [1] [1]

11 © UCLES 2013 0654/53/O/N/13 For Examiner's Use (b) (i) Place about 1 cm3 of solution X in a test-tube and add sodium hydroxide solution until the test-tube is three quarters full. Filter the mixture. Record in Table 3.2 your observations and conclusion about any ions present. (ii) 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 conclusion about any ions present. (iii) Place about 1 cm3 of solution X in a test-tube and add sodium carbonate solution until the test-tube is three quarters full. Record in Table 3.2 your observations. Table 3.2 test observations conclusion (i) sodium hydroxide solution [2] [1] (ii) ammonia solution [2] [2] (iii) sodium carbonate solution [1] (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 0654/53/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 0654 CO-ORDINATED SCIENCES 0654/53 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.

Page 2 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 53 © Cambridge International Examinations 2013 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) (i) all four sections of the table filled in ; first row shows Benedict’s solution blue ; [2] (ii) tube B: (reducing) sugar present / not present ; (conclusion must match observation) because starch digested to sugar / sugar absorbed by seed / other good explanation ; (reason must match conclusion) [2] tube D: (reducing) sugar not present ; because seeds are dead / starch not digested ; [2] (c) improved reliability / because one seed might not be active / owtte ; [1] (d) (i) larger brown areas / less starch present ; [1] (ii) smaller brown areas / more starch present ; [1] [Total: 15]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 53 © Cambridge International Examinations 2013 2 (a) (i) reading for x when d = 55 cm to nearest mm ; [1] (ii) note reading on either side of mass and find the mean value / measure mass and divide by 2 to find centre mark ; [1] (iii) complete set of x values ; x values increasing down the table ; [2] (b) (i) axes labelled with units ; 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 straight line judgement ; [4] (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, to 2 / 3 significant figures) AND correct rounding required ; [1] (d) (i) both values present, and realistic ; both values to nearest millimetre ; [2] (ii) correct calculation of density (from candidate’s values and at least 2 significant figures) ; accuracy mark: value within ± 0.1 of Supervisor’s value ; [2] [Total: 15]

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0654 53 © Cambridge International Examinations 2013 3 Table 3.1 test observation conclusion (a) (i) dilute nitric acid no reaction / nothing / paler solution ; no carbonate / no CO3 2– ; (ii) barium chloride solution ppt of stated colour ; sulfate / SO4 2– ; (iii) silver nitrate solution white ppt ; chloride / Cl – ; [6] Table 3.2 test observation conclusion (b) (i) sodium hydroxide solution brown / orange / red-brown / yellow-brown AND ppt / residue ; colourless filtrate ; iron(III) / Fe3+ ; (ii) ammonia solution brown / orange / red-brown / yellow-brown AND ppt residue ; dark blue filtrate ; iron(III) / Fe3+ ; copper(II) / Cu2+ ; (iii) sodium carbonate solution brown ppt ; [8] (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: 15]