Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2016 May/June Paper 6 · Variant 1

This document consists of 18 printed pages and 2 blank pages. DC (NH/FD) 111323/4 © UCLES 2016 [Turn over * 3 0 0 2 7 1 8 2 4 1 * CO-ORDINATED SCIENCES 0654/61 Paper 6 Alternative to Practical May/June 2016 1 hour Candidates answer on the Question Paper. No Additional Materials are required. 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. 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. Cambridge International Examinations Cambridge International General Certificate of Secondary Education

2 0654/61/M/J/16 © UCLES 2016 1 A student investigates the effectiveness of using an enzyme in the extraction of apple juice. He has two beakers of apple pulp warmed to a temperature of 35 °C. • He adds 2 cm3 of enzyme solution to beaker A and 2 cm3 of distilled water to beaker B and mixes the contents of each beaker. • He returns the beakers to the water-bath and immediately starts a stopclock. • After five minutes he empties the contents of both beakers into separate filter funnels as shown in Fig. 1.1. • He records in Table 1.1 the volume of the juice collected in each measuring cylinder every 2 minutes for a total of 10 minutes. 25 cm3 beaker A apple pulp and enzyme filter paper measuring cylinder A 25 cm3 beaker B apple pulp and water measuring cylinder B filter paper Fig. 1.1 (a) Insert headings, including units, in Table 1.1. [2] Table 1.1 … / … … / … cylinder A cylinder B 2 3.6 0.0 4 5.3 0.3 6 8 7.5 0.5 10 8.1 0.5

3 0654/61/M/J/16 © UCLES 2016 [Turn over (b) Fig. 1.2 shows the volume of juice in measuring cylinders A and B after 6 minutes. Read these volumes and enter the values in Table 1.1. [2] 6 7 8 9 1 0 2 3 4 measuring cylinder A measuring cylinder B Fig. 1.2 (c) On the grid provided, plot a graph of the results in measuring cylinder A only (vertical axis) against the values in column one of Table 1.1. Draw the best-fit line. [4] (d) Enzymes are used for juice extraction in the fruit juice industry. Use the results to suggest an advantage to manufacturers in using an enzyme in the production of fruit juice. …[1] (e) Explain how beaker B acts as a control. …[1]

4 0654/61/M/J/16 © UCLES 2016 2 A student is given three solutions C, D and E of acid X. He does not know the concentrations of the solutions. (a) The student carries out an investigation to find out the concentration of each solution. • Using a measuring cylinder he places 5 cm3 of solution C in a test-tube. • He adds a 1 cm piece of magnesium ribbon to this test-tube and starts the stopclock. • When the magnesium ribbon has completely reacted and disappeared he stops the stopclock. • If the magnesium ribbon is still present after 3 minutes, he records this time as >180 s. • He repeats the above procedure for solutions D and E. The time for solutions C and D have been entered in Table 2.1. The times are in seconds. Table 2.1 solution of acid X time taken for magnesium to disappear / s C 42 D >180 E (i) Fig. 2.1 shows the stopclock reading for solution E. Record the reading on the stopclock in Table 2.1. [1] Fig. 2.1

5 0654/61/M/J/16 © UCLES 2016 [Turn over (ii) Use the results in Table 2.1 to draw a line from each solution to its concentration. solution C solution D solution E 0.5 mol / dm3 1.0 mol / dm3 2.0 mol / dm3 least concentrated most concentrated [2] (b) Plan, in detail, another experiment that you could carry out to confirm the concentration of solutions C, D and E. The experiment must be different to the one in (a). You may use any of the chemicals in the following list but you do NOT have to use all of them. Choose a chemical or chemicals which you know will react with acids. barium chloride solution limewater magnesium ribbon marble chips silver nitrate solution sodium hydroxide solution Universal Indicator solution State clearly: • what you will do to carry out a fair test • what apparatus you will use • what observations and measurements you will make • how you will use your observations and measurements to make conclusions. … … … … … …[5]

6 0654/61/M/J/16 © UCLES 2016 (c) The student is told that acid X is hydrochloric acid. He carries out one test on X to confirm the identity of the negative ion in X. He uses only chemical reagents from the list in (b) to do this. Record in column one of Table 2.2 the chemical reagent he should use and in column two the expected observation. Table 2.2 chemical reagent observations [1] (d) The teacher suggests it would be difficult to carry out the experiment in (a) for concentrations of acid less than 0.001 mol / dm3. Explain why the teacher is correct. … …[1]

7 0654/61/M/J/16 © UCLES 2016 [Turn over 3 A student measures the mass of a metre rule using a balancing method. He uses a load L of 100 g, a metre rule and a pivot. L 0.0 cm 100.0 cm 50.0 cm mark d x y p Fig. 3.1 • He places the load on the rule so that its centre is at a distance d = 5.0 cm from the zero end of the rule, as shown in Fig. 3.1. • He adjusts the position of the pivot so that the rule balances on it. (a) Fig. 3.2 shows the position of the pivot at balance. Record in Table 3.1 on page 8, to the nearest 0.1 cm, the distance p from the pivot to the zero end of the rule. [1] 28 29 30 31 pivot Fig. 3.2

8 0654/61/M/J/16 © UCLES 2016 (b) The student repeats the procedure in (a) for values of d of 10.0 cm, 15.0 cm, 20.0 cm and 25.0 cm. His results are given in Table 3.1. Table 3.1 d / cm p / cm x = (p – d) / cm y = (50 – p) / cm 5.0 10.0 31.8 21.8 18.2 15.0 34.1 20.0 36.4 25.0 38.6 For each value of d, calculate the distances x and y as shown in Table 3.1 using the equations shown. One has been done for you. x = (p – d) y = (50 – p) Record in Table 3.1 your calculated values of x and y. [2]

9 0654/61/M/J/16 © UCLES 2016 [Turn over (c) (i) On the grid provided plot a graph of y against x. You do not need to start your axes from the origin (0, 0). Draw the best-fit straight line. y / cm x / cm [3] (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 of line = …[2]

10 0654/61/M/J/16 © UCLES 2016 (d) The mass in grams of the metre rule is given by the equation shown. mass = 100 gradient Use this equation to calculate the mass of the rule, giving your answer to an appropriate number of significant figures. mass of rule = …g [1] (e) The student now checks his result and measures the mass of the rule using a digital balance. Suggest one practical reason why, despite carrying out the experiment with care, the value for the mass calculated in (d) may be different from the value recorded by the digital balance. Assume that the digital balance used is accurate. … …[1]

11 0654/61/M/J/16 © UCLES 2016 [Turn over Please turn over for Question 4.

12 0654/61/M/J/16 © UCLES 2016 4 A student investigates whether plants need carbon dioxide for photosynthesis. He sets up two experiments, F and G, as shown in Fig. 4.1. The plants have previously been destarched. flask F substance S experiment F experiment G substance T flask G Fig. 4.1 (a) Describe how the plants are destarched. … … …[2] (b) The student needs to remove carbon dioxide from flask F. (i) Name a solid or a liquid that can be used for substance S that would remove carbon dioxide from flask F. …[1] (ii) Suggest a suitable substance T, to make experiment G a control. …[1]

13 0654/61/M/J/16 © UCLES 2016 [Turn over (c) After several hours, the student removes the leaves from the two flasks and tests them for starch. (i) Describe in detail the procedure for testing a leaf for starch. In your answer, include any safety precautions. … … … … … …[4] (ii) Describe and explain the appearance of each leaf after testing for starch. … … …[2]

14 0654/61/M/J/16 © UCLES 2016 5 (a) A student investigates solid M, which is a green powder. She places a portion of M in a beaker and adds some sulfuric acid. She observes bubbles and a gas is evolved. The teacher says the gas evolved is carbon dioxide. (i) State the test the student could use to show that the gas is carbon dioxide. Give the positive result. test … positive result …[2] (ii) The student separates the mixture produced in (a)(i) to give a blue solution. Draw a labelled diagram to show how she could produce the blue solution from the mixture. [2]

15 0654/61/M/J/16 © UCLES 2016 [Turn over (iii) The student pours the blue solution produced in (a)(ii) into three test-tubes. To one of the test-tubes she adds aqueous ammonia in small amounts until there is no further change. To the second test-tube she adds aqueous sodium hydroxide in small amounts until there is no further change. Complete Table 5.1 with the expected observations that show the blue solution contains copper(II) ions. Table 5.1 reagent aqueous ammonia aqueous sodium hydroxide observations on adding a small amount of reagent observations on adding an excess of reagent [3] (b) Use the information from part (a) to identify solid M. solid M is …[1] (c) The student uses the third test-tube of blue solution from (a)(iii) to show that the solution contains sulfate ions. Describe how she shows that the solution contains sulfate ions. State any chemicals she should use and the observations for a positive result. … … … …[2]

16 0654/61/M/J/16 © UCLES 2016 6 (a) A student investigates how much thermal energy is produced by an electric heater. She pours some water into a measuring cylinder. She records the volume of water and places the water into a beaker. Fig. 6.1 shows part of the measuring cylinder. 100 110 115 105 cm3 Fig. 6.1 (i) Read the volume of water and record the value to the nearest cm3. volume of water … cm3 [1] The student places an electric heater in the beaker of water as shown in Fig. 6.2. thermometer beaker water electric heater Fig. 6.2

17 0654/61/M/J/16 © UCLES 2016 [Turn over (ii) Draw a circuit diagram, using appropriate circuit symbols, in Fig. 6.3. Include the following: • an ammeter to measure the current in the heater • a voltmeter to measure the potential difference across the heater • a switch and a lamp in series with the heater. Fig. 6.3 [4]

18 0654/61/M/J/16 © UCLES 2016 (iii) The student measures the temperature of the water. She closes the switch to turn on the heater. After some time she opens the switch and measures the temperature of the hot water. Record the values shown on the thermometers in Fig. 6.4 in the spaces below, and calculate the temperature rise ΔT. 20 30 40 50 °C temperature before heating temperature after heating °C Fig. 6.4 temperature after heating …°C temperature before heating …°C ΔT …°C [2] (iv) Calculate the energy gained, in kJ, by the water using the equation shown. energy gained = M × ΔT × 4.2 1000 M is the mass of water used and 1 cm3 has a mass of 1 g. energy gained = … kJ [1] (b) The teacher says that not all the thermal energy produced by the heater results in a rise in the temperature of the water. Suggest two other places to which the energy could be transferred. 1 … 2 …[2]

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® IGCSE is the registered trademark of Cambridge International Examinations. This document consists of 4 printed pages. © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education CO-ORDINATED SCIENCES 0654/61 Paper 6 Alternative to Practical May/June 2016 MARK SCHEME Maximum Mark: 60 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 May/June 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 – May/June 2016 0654 61 © Cambridge International Examinations 2016 1 (a) time / minutes ; volume / cm3 ; [2] (b) 6.8 ; 0.5 ; [2] (c) both axes labelled at least one with units ; linear scale covering >1 / 2 paper ; at least 4 plots correct ± half square ; best fit line ; [4] (d) increases amount of juice produced / more juice per unit time ; [1] (e) keeps volume in each beaker constant / show that the water of enzyme solution does not have an effect / no effect without enzyme ; [1] [Total: 10] 2 (a) (i) 124 ; [1] (ii) C is 2.00 mol dm–3 D is 0.50 mol dm–3 E is 1.00 mol dm–3 ;; [2] one correct = 1 mark, three correct = 2 marks (b) add marble chip / add UI / add Mg ; (marble chips or magnesium) count bubbles / collect gas / measure volume of gas ; in a certain time ; OR (for marble chips) time ; for limewater to go milky ; OR add NaOH from measuring cylinder / burette ; until UI just green ; the more bubbles or gas the more concentrated / the shorter the time (for limewater) the more concentrated / the more NaOH the more concentrated ; equal volumes of the acids (in test–tubes) ; [5] (c) (acidified) silver nitrate / AgNO3 AND white ppt. ; [1] (d) too long for magnesium to disappear / reaction too slow ; [1] [Total: 10]

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 61 © Cambridge International Examinations 2016 3 (a) p = 29.5 cm ; [1] (b) x values correct (e.c.f. p) 24.5 ecf, (21.8), 19.1, 16.4, 13.6 ; y values correct 20.5 ecf, (18.2), 15.9, 13.6, 11.4 ; [2] (c) (i) suitable choice of scales ⩾ ½ the grid (can plot the 5 points) used AND linear ; minimum 4 plots correct to ½ small square on easy to read scale ; good best fit straight line judgement ; [3] (ii) indication on graph of how the data were obtained AND more than half the line ; calculation correct ; [2] (d) m correct to 2 / 3 significant figures ; [1] (e) Any one from: difficulty in obtaining balance ; centre of mass of rule not at the 50.0 cm mark ; load not uniform ; difficulty in placing the centre of load over the mark on the rule ; [1] [Total: 10] 4 (a) placed in the dark ; at least 24 hours ; [2] (b) (i) potassium hydroxide / sodium hydroxide / soda lime ; [1] (ii) any in the same state as (i) that does not absorb CO2 ; [1] (c) (i) iodine solution ; boiling / hot water ; hot alcohol / ethanol ; rinse with water ; (safety) water bath / not naked flame ; [max 4] (ii) G is blue-black AND F is brown / orange ; (because) G can photosynthesise and F cannot (photosynthesise) ; OR F is brown no photosynthesis ; G is blue-black can photosynthesise ; [2] [Total: 10]

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2016 0654 61 © Cambridge International Examinations 2016 5 (a) (i) limewater ; white ppt. ; [2] (ii) diagram showing filter funnel and paper ; two relevant labels ; [2] (iii) blue ppt. AND blue ppt. ; (deep) blue solution ; blue ppt. ; [3] (b) copper carbonate / CuCO3 ; [1] (c) use of (acidified aqueous) barium chloride / barium nitrate ; white ppt. etc. ; [2] [Total: 10] 6 (a) (i) 112 ; [1] (ii) correct symbol for ammeter and voltmeter ; ammeter in series and voltmeter in parallel ; correct symbols for lamp and switch in series ; workable circuit (no short circuits, no gaps) ; [4] (iii) 54 and 21 ; 33 (ecf) ; [2] (iv) 112 (ecf) × 33 (ecf) × 4.2 / 1000 = 15.5 / 16 ; [1] (b) air / surroundings ; wires / leads / (heater) casing / circuit ; AVP e.g. heat transferred to: beaker / used in evaporation ; [max 2] [Total: 10]