Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2016 Oct/Nov Paper 5 · Variant 3

This document consists of 11 printed pages and 1 blank page. DC (LK/SW) 119209/4 © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 4 4 3 8 0 9 3 1 6 5 * CO-ORDINATED SCIENCES 0654/53 Paper 5 Practical Test October/November 2016 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. For Examiner’s Use 1 2 3 Total

2 0654/53/O/N/16 © UCLES 2016 1 You are going to investigate the nutrient content of soft cheese and apples. You are provided with three testing solutions. Benedict’s solution biuret solution iodine solution • Add a small amount of distilled water to the soft cheese and stir with the stirring rod so that it loosens and can be poured. • Label the three test-tubes A, B and C. • Pour the soft cheese into each of the test-tubes to a depth of about 1 cm. • A hot water-bath is available if required. (a) Complete Table 1.1 to show which solution you are going to use for each test and whether heat is needed for the test. Table 1.1 nutrient tested for testing solution heat needed (yes / no) protein reducing sugar starch [3] (b) Test your samples of soft cheese as follows. • In test-tube A use Benedict’s solution and record in Table 1.2 your observation. • In test-tube B use biuret solution and record in Table 1.2 your observation. • In test-tube C use iodine solution and record in Table 1.2 your observation. Complete Table 1.2 by stating for each observation if the result is positive or negative for each of the tests carried out on the soft cheese. Table 1.2 testing solution used observation result Benedict’s biuret iodine [3]

3 0654/53/O/N/16 © UCLES 2016 [Turn over (c) From the piece of apple provided, remove the skin and any brown parts on the outside of the flesh. Chop the flesh of the apple into very small pieces and place about 2 cm depth into each of three clean test-tubes, labelled D, E and F. Repeat the procedure in (b) using the apple flesh instead of soft cheese. Complete Table 1.3 by stating for each observation if the result is positive or negative for each of the tests carried out on the apple. Table 1.3 testing solution used observation result Benedict’s biuret iodine [3] (d) (i) Plan an investigation to compare the reducing sugar content of lemon juice and lemonade (lemon soda). In your answer you should suggest the observations that would enable you to state which liquid has the higher concentration of reducing sugar. … … … … … …[3] (ii) Suggest why it would be difficult to compare the reducing sugar contents if orange juice is used instead of lemon juice in (d)(i). …[1] (e) Describe how you could test the apple flesh for the presence of fat. procedure … … observation for positive result … … [2]

4 0654/53/O/N/16 © UCLES 2016 2 You are going to investigate how the concentration of hydrochloric acid affects the speed of reaction between calcium carbonate and hydrochloric acid. You are provided with marble chips (calcium carbonate) and solution H which is hydrochloric acid of concentration 1.00 Q where Q is a unit of concentration. (a) (i) • Place limewater in test-tube J up to the mark. • Place solution H in test-tube K up to the mark. • Place a delivery tube in the limewater in test-tube J. • Zero the stopwatch. • Add ten marble chips to test-tube K and quickly attach the bung of the delivery tube so that the gas produced passes into the limewater in test-tube J. Start the stopwatch. • Stop the stopwatch at the first appearance of a white precipitate or milkiness in the limewater. • Record to the nearest second in Table 2.1 this time t1 for concentration 1.00 Q. [1] Table 2.1 concentration of hydrochloric acid time t1 for white ppt. to appear / s time t2 for white ppt. to appear / s average time ta for white ppt. to appear / s speed of reaction 1 ta 1.00 Q 0.75 Q 0.50 Q (ii) Rinse out the test-tubes and the delivery tube with water, placing the used marble chips in the container labelled used chips. Repeat (a)(i) and record to the nearest second in Table 2.1 the time t2 for concentration 1.00 Q. [1]

5 0654/53/O/N/16 © UCLES 2016 [Turn over (iii) You are going to make up solutions of hydrochloric acid which are less concentrated than solution H. Table 2.2 shows how to make different concentrations of hydrochloric acid. Table 2.2 volume of H / cm3 volume of water / cm3 resulting concentration of hydrochloric acid 20 0 1.00 Q 15 5 0.75 Q 10 10 0.50 Q • You will begin by making a solution of concentration 0.75 Q. • Using a 25 cm3 measuring cylinder, place 15 cm3 of solution H in a small beaker. • Add 5 cm3 of water to the small beaker and stir the mixture well. Repeat (a)(i) and (a)(ii) using this more dilute hydrochloric acid and record to the nearest second in Table 2.1 the times t1 and t2 for concentration 0.75 Q. [1] (iv) Repeat the procedure in (a)(iii), using the information in Table 2.2, to make hydrochloric acid of concentration 0.50 Q. Then repeat (a)(i) and (a)(ii) using hydrochloric acid of concentration 0.50 Q. Record your results in Table 2.1. [1] (b) (i) Calculate the average time ta for each concentration of hydrochloric acid. Record the values in Table 2.1. [1] (ii) For each concentration of hydrochloric acid, calculate 1 ta . 1 ta is a measure of the speed of reaction. Record in Table 2.1 these values to three decimal places. [1]

6 0654/53/O/N/16 © UCLES 2016 (c) (i) On the grid provided, plot a graph of the speed of reaction, 1 ta , against the concentration of hydrochloric acid used. Draw the most appropriate line through the origin. 0 0 speed of reaction 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 concentration of acid / Q 1 ta [3]

7 0654/53/O/N/16 © UCLES 2016 [Turn over (ii) Using your graph, state the relationship between the speed of the reaction and the concentration of hydrochloric acid. … …[1] (d) Explain why it is important to replace the marble chips for each experiment. … … …[1] (e) A student suggests that another experiment should be carried out using hydrochloric acid of concentration 0.25 Q. (i) Explain how this would improve the investigation. … … …[1] (ii) State the volumes of H and water required to make a solution of hydrochloric acid of concentration 0.25 Q. volume of H … cm3 volume of water … cm3 [1] (f) Temperature affects the speed of reaction. The reaction between calcium carbonate and hydrochloric acid is exothermic. Consider this information and suggest how temperature affects the speed of reaction. Explain your answer. … … …[2]

8 0654/53/O/N/16 © UCLES 2016 3 You are going to investigate the effective resistance of different combinations of identical resistors. The circuit shown in Fig. 3.1 has been set up for you. A X Y R R R power source switch Fig. 3.1 (a) (i) Switch on the circuit by closing the switch. Use the voltmeter provided to measure the potential difference V between points X and Y. Record V and switch off the circuit by opening the switch. V = … V [1] (ii) Complete Fig. 3.1, to show how the voltmeter is connected to measure V in (a)(i). [2] (iii) Close the switch. Record the current I shown on the ammeter and then open the switch. I = … A [1] (iv) Calculate the total resistance RT between points X and Y using the equation shown. RT = Include the unit of resistance in your answer. RT = … unit = … [2] V I

9 0654/53/O/N/16 © UCLES 2016 [Turn over (b) Disconnect the resistors from the circuit. Reconnect the resistors in the circuit so that all three resistors are in series between points X and Y. (i) Complete the circuit diagram in Fig. 3.2 to show the resistors connected in series between points X and Y. A X Y power source switch [1] Fig. 3.2 (ii) Close the switch. Use the voltmeter to measure the potential difference VS between points X and Y. Record VS and then open the switch. VS = … V [1] (iii) Close the switch. Record the current IS shown on the ammeter and then open the switch. IS = … A [2] (iv) Calculate the resistance RS of the series combination of the three resistors using the equation shown. RS = RS = …[2] VS IS

10 0654/53/O/N/16 © UCLES 2016 (c) Theory suggests that, because the resistors are identical the following relationship exists. RT = 0.5 RS State whether your results support the theory. Justify your statement by reference to your results. statement … justification … … [1] (d) Explain why it is important to open the switch between taking readings. … …[1] (e) Predict how the reading on the ammeter changes if the three resistors are replaced by just one of the resistors connected between points X and Y. Assume that the potential difference between points X and Y stays the same. …[1]

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12 0654/53/O/N/16 © UCLES 2016 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. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series. 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. 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 with dilute nitric acid, then add 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 result ammonia (NH3) turns damp red litmus paper blue carbon dioxide (CO2) turns limewater milky chlorine (Cl 2) 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. This document consists of 6 printed pages. © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education CO-ORDINATED SCIENCES 0654/53 Paper 5 Practical Test October/November 2016 MARK SCHEME Maximum Mark: 45 Published 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 2016 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 2016 0654 53 © UCLES 2016 Question Answer Marks 1(a) nutrient tested for testing solution heat needed (yes / no) Protein biuret no Reducing sugar Benedict’s yes Starch iodine no 3 one testing solution correct ; three testing solutions correct ; heat for reducing sugar only ; 1(b) testing solution observation result Benedict’s blue negative biuret purple / lilac positive iodine orange negative 3 1 mark per row ;;;

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0654 53 © UCLES 2016 Question Answer Marks 1(c) test solution used observation result Benedict’s yellow / green / orange / red positive biuret blue negative iodine orange negative 3 1 mark per row ;;; 1(d)(i) same volume of juice ; same volume of Benedict’s solution ; yellow / green for small amount of reducing sugar OR orange / red for higher amount of reducing sugar ; 3 1(d)(ii) colour of orange juice masks colour of results / orange is one of Benedict’s possible colours ; 1 1(e) dissolve in alcohol AND add water ; milky / cloudy / emulsion ; 2 Total: 15

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0654 53 © UCLES 2016 Question Answer Marks 2(a)(i) value for t1 for 1.00 Q ; 1 2(a)(ii) value for t2 for 1.00 Q AND (a)(i) and (ii) to nearest second ; 1 2(a)(iii) values for t1 and t2 for 0.75 Q AND values of t greater than those for 1.00 Q (on average) ; 1 2(a)(iv) values for t1 and t2 for 0.50 Q AND values of t greater than those for 0.75 Q (on average) ; 1 2(b)(i) all average times ta correct ; 1 2(b)(ii) all 1/ta values correct AND to 3dp ; 1 2(c)(i) linear vertical scale from zero using at least half of the grid ; all three points plotted correctly to within half a small square ; best appropriate line through the origin ; 3 2(c)(ii) statement of relationship between rate and concentration appropriate for line ; 1 2(d) reacted chips will have a smaller surface area / already reacted chips will react slower ; 1 2(e)(i) relationship more reliable / easier to decide position or type of line ; 1 2(e)(ii) (volume of H)….……5……..AND (volume of water)……15 ; 1

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0654 53 © UCLES 2016 Question Answer Marks 2(f) speed was increased / rate was increased ; by increase in temperature / by more energetic collisions ; 2 Total: 15 Question Answer Marks 3(a)(i) V recorded ; 1 3(a)(ii) correct symbol for voltmeter ; correct parallel voltmeter connection ; 2 3(a)(iii) I recorded ; 1 3(a)(iv) RT calculation correct ; ohm / Ω ; 2 3(b)(i) correct series circuit ; 1 3(b)(ii) Vs recorded to at least 1 decimal place AND less than 3 V ; 1 3(b)(iii) Is recorded to at least 2 decimal places AND less than 1 A ; Is less than I ; 2 3(b)(iv) Rs calculation correct ; 2 / 3 significant figures ; 2 3(c) (statement) – yes AND (justification) – values of RT and 0.5 R2 are close enough / difference can be attributed to experimental error ; 1 3(d) resistors become hot / resistor values may change ; 1

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0654 53 © UCLES 2016 Question Answer Marks 3(e) reading increases / current is greater ; 1 Total: 15