Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2014 Oct/Nov Paper 5 · Variant 2

This document consists of 12 printed pages. IB14 11_0654_52/5RP © UCLES 2014 [Turn over *9445251805* For Examiner's Use 1 2 3 Total Cambridge International Examinations Cambridge International General Certificate of Secondary Education CO-ORDINATED SCIENCES 0654/52 Paper 5 Practical Test October/November 2014 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 an HB 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. Notes for Use in Qualitative Analysis 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 2014 0654/52/O/N/14 1 You are going to investigate the action of the enzyme amylase on starch. • Label two test-tubes A and B. • Measure 10 cm3 starch solution into each of tubes A and B and place them in a water-bath at 30 °C. • Place tube C, which contains amylase solution, into the water-bath. • Place tube D, which contains boiled amylase solution, into the water-bath. • Start the stopclock. • Wait five minutes. During this time, add two drops of iodine solution to each of ten wells in the spotting tile. Label five of the wells ‘A’ and five of the wells ‘B’ as shown in Fig. 1.1. B B B B B A A A A A pipette spotting tile iodine Fig. 1.1 • When at least five minutes have elapsed on your stopclock, stop and zero the stopclock. • Pour the contents of tube C into tube A. • Pour the contents of tube D into tube B. • Start the stopclock. (a) Immediately, using a clean dropping pipette, place two drops from tube A into one of the wells containing iodine solution labelled A in the spotting tile. Record in Table 1.1 the colour obtained. Using a second clean dropping pipette, repeat with tube B into one of the wells containing iodine solution labelled B in the spotting tile. Record in Table 1.1 the colour obtained. Repeat this procedure for tube A and tube B at one minute intervals for a further four minutes. Continue to keep the samples from tube A and tube B separate. [4]

3 © UCLES 2014 0654/52/O/N/14 [Turn over Table 1.1 time / minutes colour of solution from tube A when added to iodine solution colour of solution from tube B when added to iodine solution 0 1 2 3 4 (b) Explain why you left the tubes in the water-bath for five minutes at the start. [1] (c) By referring to the colours recorded in Table 1.1, state and explain what happens to the starch in tube A during the experiment and what can be concluded about the action of the amylase on the starch in tube A by the end of the experiment. [3] (d) (i) State what can be concluded about the presence of starch in tube B at the end of the experiment. [1] (ii) Explain your answer to (i). [2]

4 © UCLES 2014 0654/52/O/N/14 (e) Suggest one source of error for this experiment. [1] (f) Suggest how you could change this method to investigate the effect of different temperatures on amylase activity. [3]

5 © UCLES 2014 0654/52/O/N/14 [Turn over Please turn over for Question 2.

6 © UCLES 2014 0654/52/O/N/14 2 You are provided with 1 g of each of three salts P, Q and R. You are going to investigate the temperature changes when these salts are dissolved in water. You will also identify some of the ions in salts P, Q and R. (a) (i) Measure 25 cm3 distilled water into a beaker. Use a thermometer to measure the initial temperature of the distilled water. Record this value as the initial temperature for salt P, to the nearest 0.5 °C, in the appropriate space in Table 2.1. [1] (ii) Add the sample of salt P to the distilled water in the beaker and stir well. Observe the highest temperature if the temperature rises or the lowest temperature if the temperature falls. Record this temperature, to the nearest 0.5 °C, in the appropriate space in Table 2.1. Transfer the resulting solution of P to a labelled test-tube for use in (c)(i). [1] (iii) Wash out the beaker thoroughly. Repeat (a)(i) and (a)(ii) using salt Q instead of salt P. Transfer the resulting solution of Q to a labelled test-tube for use in (c)(ii). [1] (iv) Wash out the beaker thoroughly. Repeat (a)(i) and (a)(ii) using salt R instead of salt P. Transfer the resulting solution of R to a labelled test-tube for use in (c)(iii). [1] Table 2.1 salt P salt Q salt R initial temperature / °C final temperature / °C change in temperature / °C (b) (i) Using the initial and final temperatures in Table 2.1, calculate any temperature change for each of salts P, Q and R dissolving in water. Record any changes in Table 2.1. Place a plus (+) sign in front of a temperature rise and a minus (-) sign in front of a temperature fall. [2] (ii) Name the type of heat energy change you observed when salt P dissolved in water. [1]

7 © UCLES 2014 0654/52/O/N/14 [Turn over (c) (i) Pour about 5 cm3 of the solution of salt P into a clean test-tube. Add dilute sodium hydroxide until there is no further change. Record your observations below and identify the cation in salt P. observations identity of the cation in P [2] (ii) Pour about 4 cm3 of the solution of salt Q into a clean test-tube. Add an equal volume of dilute sodium hydroxide. Gently warm the test-tube and hold a piece of damp red litmus above the mouth of the test-tube. Record your observations below. Identify any gas produced and the cation in salt Q. observations name of gas identity of the cation in Q [3] (iii) Divide the test-tube of the solution of salt R into two test-tubes. To one portion add aqueous barium chloride and to the other add aqueous silver nitrate. Construct a suitable table with headings in the space below and record your observations and conclusions for salt R in the table. [3]

8 © UCLES 2014 0654/52/O/N/14 3 You are going to measure the extension of a spring when different masses m are added to it, and plot a graph. You will then use the spring to measure the density of a stone. A spring has been set up in a clamp for you, as shown in Fig. 3.1. spring clamp stand Fig 3.1 (a) (i) Measure and record the length l0 of the unstretched spring to the nearest millimetre. l0 = mm [1] (ii) Draw an arrow on Fig. 3.1 to show the length l0 you measured. [1] (iii) Hang a mass m of 100 g on the spring. Measure the new length l of the spring to the nearest millimetre. Record the mass m and the length l in Table 3.1. [1] (iv) Calculate the extension e of the spring, using the equation e = l – l0 Record the value of e in Table 3.1. [1]

9 © UCLES 2014 0654/52/O/N/14 [Turn over (v) Repeat steps (iii) and (iv) using masses of 200 g, 300 g, 400 g and 500 g and complete Table 3.1. [3] Table 3.1 mass m / g spring length l / mm extension e / mm (b) On the grid provided, plot a graph of m against e. Start both axes from the origin (0,0). Draw the best fit straight line. [3] m / g e / mm

10 © UCLES 2014 0654/52/O/N/14 (c) (i) Remove the masses from the spring. Attach the stone provided to the spring. Measure the length lA of the spring and calculate the extension eA of the spring caused by the stone. Record your answers in the spaces below. length lA of spring = mm extension eA of spring = mm [1] (ii) Use your answer to (c)(i) and the graph in (b) to determine the mass of the stone. Show on the graph how you obtained your answer. mass of stone = g [1] (d) Place the beaker of water under the stone. Slowly lower the clamp until the stone is completely immersed in the water, as shown in Fig. 3.2. spring water stone clamp stand Fig 3.2 (i) Measure the length lW of the spring and calculate the extension eW of the spring. Record your answers in the spaces below. length lW of spring = mm extension eW of spring = mm [1] (ii) Use your answers to (c)(i) and (d)(i) to calculate the density, d of the stone, using the equation d = A A w e (e - e ) density of stone d = g / cm3 [1]

11 © UCLES 2014 0654/52/O/N/14 (e) Suggest one possible improvement to the experiment to obtain a more accurate result. improvement [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. 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 2014 0654/52/O/N/14 NOTES FOR USE IN QUALITATIVE ANALYSIS 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

® IGCSE is the registered trademark of Cambridge International Examinations. CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International General Certificate of Secondary Education MARK SCHEME for the October/November 2014 series 0654 CO-ORDINATED SCIENCES 0654/52 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 2014 series for most Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level components.

Page 2 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0654 52 © Cambridge International Examinations 2014 1 (a) full set of results (colours) recorded for tube A ; full set of results (colours) for tube B ; correct trend for tube A (later samples are brown / orange) ; (check Supervisors results) correct trend for tube B (all blue-black) ; [4] (b) to reach 30 °C / give time to get to temperature ; [1] (c) amount of starch reduces / no starch by end of experiment ; brown colour appears when no more starch present ; starch is digested / starch is broken down by the amylase ; [3] (d) (i) starch is still present ; [1] (ii) amylase is, denatured / not working / inactive ; starch is not broken down ; [2] (e) difficulty in distinguishing colours by eye ; drops not all the same size ; both tubes not tested at the same time ; [max 1] (f) several water-baths at different temperatures ; compare time for samples to become brown / orange; keeping other factors constant ; [3] Total: [15] 2 (a) (i) initial temperature of P recorded to nearest 0.5 °C ; [1] (ii) sensible final temperature of P (expect: increase of 2 – 4 °C) ; [1] (iii) sensible final temperature of Q (expect: decrease of 1 – 2 °C) ; [1] (iv) sensible final temperature of R (expect: slight or no change) ; [1] (b) (i) all temperature changes correct (ignoring signs) ; all signs correct ; [2] (ii) exothermic ; [1] (c) (i) blue ppt. ; copper / Cu2+ / copper(II) ; (depends on observation of blue) (not Cu) [2] (ii) red litmus goes blue ; ammonia / NH3 ; ammonium / NH4 + ; [3]

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0654 52 © Cambridge International Examinations 2014 (iii) OR observation conclusion aqueous barium chloride no reaction not sulfate aqueous silver nitrate white ppt. chloride present labelled table ; both observations ; both conclusions ; [max 3] [Total: 15] 3 (a) (i) sensible l0 (check Supervisors values), recorded to the nearest millimetre ; [1] (ii) sensible distance, carefully marked on Fig. 3.1 ; [1] (iii) values of m (100 g) and l present in the table ; [1] (iv) extension calculated correctly (for 100 g) ; [1] (v) all readings present of mass and length present ; all lengths increasing down the table ; all extensions correct ; [3] (b) suitable choice of linear scales ; 4 points plotted correctly to ± ½ small square ; good best fit straight line judgement and through origin ; [3] (c) (i) length recorded AND extension eA correct ; [1] (ii) mass correctly read from graph ; [1] aqueous barium chloride aqueous silver nitrate observation no reaction white ppt. conclusion not sulfate chloride present

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0654 52 © Cambridge International Examinations 2014 (d) (i) length recorded AND correct extension eW less than eA ; [1] (ii) value of d calculated correctly AND between 2.0 and 3.5 (g / cm3) ; [1] (e) use of set square / fiducial aid / other sensible suggestion (e.g. clamp rule vertically) ; [1] [Total: 15]