Cambridge IGCSE Science - Combined 0653 — 2013 Oct/Nov Paper 6 · Variant 2

This document consists of 20 printed pages. IB13 11_0653_62/FP © UCLES 2013 [Turn over *4800132758* UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMBINED SCIENCE 0653/62 Paper 6 Alternative to Practical October/November 2013 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 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. 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 0653/62/O/N/13 For Examiner's Use 1 In an experiment, four Petri dishes, A, B, C and D, were 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. The experiment uses barley grains that were germinated for a few days. Some of the barley grains were then killed by being placed in boiling water. Groups of the barley grains were then placed on the starch-agar mixture in each of four dishes, and left for a few days. • In dishes A and B, the barley grains were living. • In dishes C and D, the barley grains were dead. dish A living barley grains starch-agar gel dish B living barley grains starch-agar gel dish C killed barley grains starch-agar gel dish D killed barley grains starch-agar gel Fig. 1.1

3 © UCLES 2013 0653/62/O/N/13 [Turn over For Examiner's Use (a) The barley grains were removed from dishes A and C. The gel in each of these dishes was then covered with iodine solution. The results are shown in Fig. 1.2. dish A dish C blue-black blue-black brown Fig. 1.2 (i) Describe the results in dish A. [1] (ii) Write a conclusion based on these results. [1] (iii) In dish C, dead barley grains were used. What is the purpose of dish C? [1]

4 © UCLES 2013 0653/62/O/N/13 For Examiner's Use (b) The gel in each of dishes B and D was then tested as follows: • A small piece of starch-agar gel was removed from underneath the barley grains in each dish. These pieces of gel were put into two separate test-tubes. • Five drops of Benedict’s solution were added to each test-tube. • The test-tubes were placed in a hot water bath for three minutes. • The results are shown in Table 1.1. Table 1.1 test-tube B test-tube D colour of Benedict’s solution before heating blue blue colour of Benedict’s solution after heating orange blue (i) Explain what the result in test-tube B shows. [1] (ii) Suggest a reason for this result. [1] (c) In these experiments, explain why several barley grains were used in each Petri dish, rather than just one. [1] (d) Suggest how the results in (a)(i) 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]

5 © UCLES 2013 0653/62/O/N/13 [Turn over For Examiner's Use (e) Outline an experiment that you could do to compare the effect on starch-agar gel of two different varieties of seeds. [2]

6 © UCLES 2013 0653/62/O/N/13 For Examiner's Use 2 A student is finding the mass and volume of a metre rule and then calculating the density of the material of which it is made. The teacher has given him an unknown mass, M, to use in the experiment. The apparatus is shown in Fig. 2.1. distance x distance d = 55.0 cm mass M knife edge metre rule 0 100 Fig. 2.1 • The student places the knife edge under the 55.0 cm mark of the rule so that distance d = 55.0 cm. • He places mass M on the right-hand side of the rule and adjusts its position until the rule is balanced. • He records in Table 2.1 the position of mass M on the rule and calculates x, the distance between the knife edge and the centre of mass M. • He adjusts the knife edge so that d = 60.0 cm. • He moves mass M until the rule is balanced again. • He records the new position of mass M, then calculates and records the new value of x. • He repeats the procedure for the other values of d shown in Table 2.1. (a) (i) Fig. 2.2 shows the positions of M when d = 60.0 cm and 70.0 cm. For each knife edge position, read the rule and record, in Table 2.1, the position of the centre of M. [2] (ii) Calculate the missing values of x, the distance from the knife edge to the centre of M, and record them in Table 2.1. [2] 6 5 7 0 position of knife edge = 60.0 cm 8 5 9 0 position of knife edge = 70.0 cm mass M mass M Fig. 2.2

7 © UCLES 2013 0653/62/O/N/13 [Turn over For Examiner's Use Table 2.1 distance d / cm position of mass M / cm distance x / cm 55.0 58.8 3.8 60.0 65.0 77.1 12.1 70.0 75.0 94.4 19.9 (b) (i) On the grid provided, plot a graph of d against x. Draw the best straight line. 80 75 70 65 60 55 50 0 5 10 15 20 25 x / cm d / cm [2]

8 © UCLES 2013 0653/62/O/N/13 For Examiner's Use (ii) Find the gradient of the line. Show on your graph the values that you use to calculate the gradient. gradient = [2] (c) The teacher says that the mass of the metre rule, m, is given by the equation mass of rule, m = gradient 150 Use this equation to calculate the mass of the rule. m = g [1] (d) The student measures the dimensions of the metre rule, shown in Fig. 2.3. He wants to use the mass and volume of the rule to determine the density of the material. width, w thickness, t length, l Fig. 2.3 Use the symbols l, w, t and m to write a formula that the student can use to find the density. density of the material = [1]

9 © UCLES 2013 0653/62/O/N/13 [Turn over Please turn over for Question 3.

10 © UCLES 2013 0653/62/O/N/13 For Examiner's Use 3 A student is carrying out tests to identify the ions present in solution X. Table 3.1 shows the tests, observations and conclusions that he has made. Complete Table 3.1. Table 3.1 test observation conclusion (a) (i) To a spatula load of solid X, slowly add dilute nitric acid, with shaking, until the solid has dissolved. Divide the solution into two parts, for use in (a)(iii) and (b)(i). Some are seen rising in the solution. A green solution is formed. [1] A gas is given off. Solid X contains ions of metals known as [1] (ii) Test the gas given off from (a)(i) using limewater. The limewater turns [1] Solid X contains carbonate ions. (iii) To the first part of the solution from (a)(i) add an equal volume of aqueous silver nitrate. A is formed. [1] Solid X contains chloride ions. (b) (i) To the second part of the solution from (a)(i) add ammonia solution, with shaking, until it is in excess. Filter the mixture. A brown precipitate and a dark blue filtrate are obtained. The brown precipitate is iron(III) [1]

11 © UCLES 2013 0653/62/O/N/13 [Turn over For Examiner's Use test observation conclusion (ii) To a sample of the filtrate from (b)(i) add dilute sulfuric acid until the mixture is just acid. Test with paper to show that the mixture is acid. [1] The colour of the mixture of the filtrate with dilute sulfuric acid is [1] The filtrate contains copper(II) ions. (iii) To a sample of the residue from (b)(i) add hydrochloric acid and shake until it has dissolved. The colour of the solution is [1] The residue contains iron(III) ions. (c) The student has concluded that solution X contains copper(II), iron(III), chloride and sulfate ions. Write the name and formula of two salts that could have been used to make solution X. name of salt 1 formula name of salt 2 formula [2]

12 © UCLES 2013 0653/62/O/N/13 For Examiner's Use 4 A student carried out an experiment to investigate the extension of a piece of artery. She set up the apparatus shown in Fig. 4.1. 0 clamp thread artery thread mass holder mass ruler length l Fig. 4.1 • The student cut a length of artery and tied it firmly at each end. • She suspended one end of the artery from a clamp. • She measured the length l as shown in Fig. 4.1. • The student then added masses 20 g at a time to the mass holder and measured the value of l after each addition. At the end of the experiment the student removed the masses and the artery recoiled (sprang back) to its original length. The results are shown in Table 4.1. Table 4.1 mass / g length l / cm 0 10.0 20 10.9 40 60 12.5 80 13.0 100 13.5 120 13.7 140 160 14.1 180 14.1 200 14.1

13 © UCLES 2013 0653/62/O/N/13 [Turn over For Examiner's Use (a) (i) Read the scales of the rulers shown in Fig. 4.2. Enter the values for l in Table 4.1. [2] 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 mass added = 40 g l 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 mass added = 140 g l artery centimetres centimetres Fig. 4.2

14 © UCLES 2013 0653/62/O/N/13 For Examiner's Use (ii) Plot a graph of length l against mass. Draw a smooth curve. [3] length l / cm (iii) Calculate the average extension of the artery per gram of mass added from 0 to 60 g, average extension = cm / g from 100 to 160 g. average extension = cm / g [2]

15 © UCLES 2013 0653/62/O/N/13 [Turn over For Examiner's Use (b) (i) The experiment was carried out on a piece of aorta. This is the artery that comes straight from the heart. Suggest an advantage to the animal of the ability of the walls of the aorta to stretch and recoil. [1] (ii) Explain why it is important for the artery to be able to cope with large forces as shown in Table 4.1. [1] (c) The student carried out a similar investigation on a piece of vein of the same length. State one other factor she should keep the same to make it a fair test. [1]

16 © UCLES 2013 0653/62/O/N/13 For Examiner's Use 5 A student is comparing three colourless samples of vinegar, A, B and C. He wants to find out how much acid is in each sample by titrating with aqueous sodium hydroxide. • He measures out 50 cm3 of sample A and places it in a conical flask. • He adds 3 drops of an indicator. • He fills a burette to the 0.0 cm3 mark with aqueous sodium hydroxide and adds it drop by drop to the conical flask until the indicator changes colour. • He reads the burette scale and records the volume in Table 5.1. • He repeats the procedure using samples B and C. Table 5.1 sample A B C volume of aqueous sodium hydroxide used / cm3 (a) (i) Fig. 5.1 shows the burette scales for samples A, B and C. Read the scales and enter the volumes in Table 5.1. 21 22 23 24 25 sample A 23 24 25 26 27 sample B 25 26 27 28 29 sample C Fig. 5.1 [3] (ii) Complete the sentence. is the most concentrated sample and is the least concentrated sample of vinegar. [1]

17 © UCLES 2013 0653/62/O/N/13 [Turn over For Examiner's Use (b) (i) Vinegar contains ethanoic acid. During the reaction between vinegar and aqueous sodium hydroxide, a salt, sodium ethanoate, is formed. Complete the word equation for the reaction between ethanoic acid and sodium hydroxide to form sodium ethanoate. ethanoic acid + sodium hydroxide + [1] (ii) Vinegar is a weak acid. Suggest what colour Universal Indicator (full-range indicator) will turn if it is added to vinegar. [1] (c) The student wants to make a sample of sodium ethanoate. Describe carefully how he can use the results of this experiment to prepare pure dry crystals of sodium ethanoate. [4]

18 © UCLES 2013 0653/62/O/N/13 For Examiner's Use 6 The science class is studying waves made by a vibrating spring. A piece of spring steel about 25 cm long has a pen fixed at one end. The other end is firmly clamped. When the spring is pulled to one side and then released, it vibrates for a few seconds. The pen makes a mark on a piece of paper that is pulled along while the spring is vibrating. This is shown in Fig. 6.1. roll of paper wave trace made by vibrating spring paper is pulled out pen attached to spring spring is pulled to one side then released straight steel spring Fig. 6.1 The paper is pulled along at a constant speed. Fig. 6.2 shows the wave drawn by the pen. A student has numbered the waves. wave number 1 2 3 Fig. 6.2 (a) (i) Describe how the amplitude of the wave changes from wave 1 to wave 3. [1] (ii) Use a ruler to measure to the nearest 0.1 cm the wavelength of one of the waves in Fig. 6.2. Use the marks that the student has made. wavelength = cm [1] (iii) The paper moved at a constant speed of 10 cm / s. Use the equation speed = frequency × wavelength and your answer to part (ii) to calculate the frequency of the waves caused by the vibration of the steel spring. frequency = Hz [2]

19 © UCLES 2013 0653/62/O/N/13 [Turn over For Examiner's Use The apparatus shown in Fig. 6.1 is then used to find the acceleration of a trolley moving down a slope. This is shown in Fig. 6.3. trolley direction of trolley track string paper vibrating spring Fig. 6.3 The spring is adjusted so that it vibrates 4 times every second. One complete wave takes 0.25 s. The trace made by the pen as the trolley moves down the slope is shown in Fig. 6.4. A student has numbered waves 1 – 9 on the trace. wave number 9 8 7 6 5 4 3 2 1 start Fig. 6.4 (b) (i) Use a ruler to measure the wavelength of wave 4 to the nearest 0.1 cm. Use the marks that the student has made. wavelength = cm [1] (ii) Calculate the average speed of the trolley at this point on the trace. Remember that one wave takes 0.25 s. Give the units of speed of the trolley. speed of the trolley at wave 4 = unit [2]

20 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 0653/62/O/N/13 For Examiner's Use (c) (i) Measure the wavelength of wave 9 to the nearest 0.1 cm. wavelength = cm [1] (ii) Calculate the average speed of the trolley at this point. speed of the trolley at wave 9 = [1] (d) Use your results from parts (b)(ii) and (c)(ii) to show that the trolley accelerates as it moves down the slope. [1]

CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2013 series 0653 COMBINED SCIENCE 0653/62 Paper 6 (Alternative to Practical), maximum raw mark 60 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 62 © Cambridge International Examinations 2013 1 (a) (i) brown colour around where the seeds / grains were, (blue / black elsewhere) ; [1] (ii) enzyme / seeds / grains breaking down / use / need / converted the starch ; [1] (iii) control / shows that breakdown depends on living seeds, ORA ; [1] (b) (i) (reducing) sugar is made (around the seeds / when the starch is broken down) ; [1] (ii) starch digested / changed / converted to sugar ; [1] (c) (improved) reliability / because one seed might not be active / owtte ; [1] (d) (i) larger brown areas ; [1] (ii) smaller brown areas (accept no brown area / all blue-black) ; [1] (e) (use different varieties of) seeds on different dishes / (different parts) of the same dish ; keep (named) conditions constant ; compare diameters / sizes of brown areas ; [max 2] [Total: 10] 2 (a) (i) 68.0 ; 86.2 (±0.1) ; [2] (ii) 8(0), 16.2 (ecf) ; ; [2] (b) (i) points plotted correctly ; (allow 1 error) suitable straight line drawn ; [2] (ii) clear evidence on graph ; allow 1.2 to 1.3 inclusive ; [2] (c) 150/candidates answer = between 125 and 115 g (ecf) ; [1] (d) density = m /l
t
w (any order) ; [1] [Total: 10]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0653 62 © Cambridge International Examinations 2013 3 (a) (i) observation: bubbles ; conclusion: transition elements / metals ; [2] (ii) milky / white / cloudy chalky ; [1] (iii) observation: white precipitate ; [1] (b) (i) hydroxide [1] (ii) test: litmus (ignore colour) or Universal Indicator ; observation: blue ; [2] (iii) brown, yellow or orange ; [1] (c) iron(III) chloride FeCl3 and copper carbonate CuCO3 ;; OR iron(III) carbonate Fe2(CO3)3 and copper chloride CuCl2 ;; [max 2] (allow 1 for two correct names or formulae) [Total: 10] 4 (a) (i) 11.7 cm (no tolerance) ; 13.9 cm (no tolerance) ; [2] (ii) suitable scale and label on x axis; not starting y axis at 0 ; smooth curve drawn ; [3] (iii) 0.0417 or 0.042 cm / g; 0.01 or 0.010 cm / g; [2] (b) (i) (allows aorta to stretch) to allow surge of blood through / recoil propels blood between beats / smoothes out blood flow / change in pressure ; [1] (ii) resistant to bursting / breaking / tearing ; [1] (c) e.g. same width of sample taken / same part of body of animal / same animal ; [1] [Total: 10]

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0653 62 © Cambridge International Examinations 2013 5 (a) (i) 22.5 ; 25.1 ; 27.8 ; [3] (ii) C is the most concentrated, A is the least concentrated ; [1] (b) (i) sodium ethanoate + water ; [1] (ii) orange or yellow, (reject red) ; [1] (c) same volume of acid and alkali ; without indicator ; evaporate ; filter ; dry crystals with e.g. filter paper ; (any 4) OR evaporate ; (heat / boil etc.) to concentrate / crystallisation point / saturation etc. ; leave or cool ; filter ; dry crystals with e.g. filter paper ; (any 4) [max 4] [Total: 10] 6 (a) (i) the amplitude decreases / gets smaller ; [1] (ii) 4.0 cm (±0.1 cm) ; [1] (iii) frequency = speed/wavelength, 10/4 ; = 2.5 (Hz) ; [2] (b) (i) 1.1 cm (±0.1 cm) ; [1] (ii) (1.1/0.25) = 4.4 (ecf) ; cm / s ; [2] (c) (i) distance = 2.2 cm (±0.1 cm) ; [1] (ii) speed = 2.2 / 0.25 = 8.8 (ignore units, ecf) ; [1] (d) speed at 9th wave is greater than speed at 4th wave, owtte (must refer to two things, wave numbers, part numbers or speeds) ; [1] [Total: 10]