Cambridge IGCSE Science - Combined 0653 — 2016 Oct/Nov Paper 6 · Variant 1

This document consists of 16 printed pages. DC (SC) 138189 © UCLES 2016 [Turn over * 2 2 3 9 1 3 3 5 2 4 * COMBINED SCIENCE 0653/61 Paper 6 Alternative to Practical October/November 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 0653/61/O/N/16 © UCLES 2016 1 A student investigates the movement of molecules through a membrane. • He places 2 cm3 of starch solution inside each of two tubes made of clear and colourless artificial membrane. He ties both ends of each tube with a knot to enclose the starch solution inside. This makes two soft tubing bags. • He places one bag into a beaker of water. This is beaker A. • He places the other bag into a beaker of iodine solution. This is beaker B. • Fig. 1.1 shows how the experiment is set up. beaker A beaker B tube of starch solution water tube of starch solution iodine solution Fig. 1.1 • He starts the stopwatch and records the appearance of the starch solution inside the tubes every 2 minutes for 10 minutes. His results are shown in Table 1.1. (a) Complete the headings in Table 1.1. Table 1.1 … / … … beaker A beaker B 0 cloudy cloudy 2 cloudy cloudy 4 cloudy cloudy 6 cloudy cloudy with some black areas 8 cloudy black 10 cloudy black  [2]

3 0653/61/O/N/16 © UCLES 2016 [Turn over (b) The artificial membrane allows some molecules to pass through it, but starch molecules are too large to pass through. Use this information and Table 1.1 to explain the observations for beaker B. … ��������������������������������������������������������������������������������������������������������������������������������������������������� … …[3] (c) (i) Amylase is an enzyme that breaks down starch into reducing sugar. The student now adds amylase to the contents of the tube in beaker B and leaves in a warm place for a few minutes. Predict what he will observe. … …[1] (ii) Explain your answer to (c)(i). … …[1] (iii) Describe a test you could carry out to confirm that reducing sugar has been produced. Include the observation for a positive result in your answer. … … … …[3]

4 0653/61/O/N/16 © UCLES 2016 2 A student is given a pale green solution J containing a dissolved salt and a grey solid L, which is an element. He carries out some experiments to identify the ions of the salt in J and to identify the element L. (a) He chooses from the following solutions to carry out tests to identify the cation and the anion in solution J. barium nitrate solution dilute nitric acid silver nitrate solution sodium hydroxide solution (i) State the details of the test and the observations which allow him to identify the cation as Fe2+. cation test … … observations … …  [2] (ii) State the details of the test and the observations which allow him to identify the anion as SO4 2–. anion test … … observations … …  [3] (b) (i) • The student places solid L in a test-tube. He adds dilute hydrochloric acid. • He warms the test-tube gently for a short time to increase the rate of reaction. • He stirs carefully and tests the gas produced. • He records in Table 2.1 his observations and the test which identifies this gas. Table 2.1 test observation add dilute hydrochloric acid fizzing and colourless solution is formed lighted splint at mouth of test-tube popping sound Identify the gas produced. gas produced …[1]

5 0653/61/O/N/16 © UCLES 2016 [Turn over (ii) • The student filters the mixture from (b)(i) into a test-tube. • To the filtrate in the test-tube he slowly adds sodium hydroxide solution until there are no further changes. • He identifies the element L as zinc. Suggest the observations which lead him to this conclusion. observations … … …[2] (c) The student then places magnesium powder in a test-tube. He adds solution J to the magnesium powder and records his observations. test-tube becomes warmer observations … After three minutes, he filters the mixture into another test-tube and records the appearance of the filtrate. colourless appearance of filtrate … He then adds sodium hydroxide solution slowly to a portion of the filtrate until there is no further change. He records his observations. faint white ppt observations … (i) Using your answers to (a) and this information, suggest what has happened to the cation in solution J. … …[1] (ii) State the name given to a reaction that gives out heat. …[1]

6 0653/61/O/N/16 © UCLES 2016 3 A student investigates how the period of a simple pendulum depends on its length. The period of a pendulum is the time for one complete swing (oscillation) of the pendulum. This is shown in Fig. 3.1, where the period is the time taken for the bob to swing from P to Q and back to P again. point of support pendulum bob P Q Fig. 3.1 She sets up the pendulum as shown in Fig. 3.2. clamp pendulum bob l bench Fig. 3.2 Fig. 3.2 is drawn to a scale of one-tenth full size. (a) (i) Measure the length l of the pendulum in Fig. 3.2 to the nearest 0.1 cm. length l = … cm [1]

7 0653/61/O/N/16 © UCLES 2016 [Turn over (ii) Calculate the actual length lA of the pendulum she uses. Record your answer below and in Table 3.1 in (b). actual length lA = …cm [1] (iii) The actual length lA of the pendulum is the distance from the point of support to the centre of the pendulum bob. Describe a precaution that the student should take to measure lA as accurately as possible. You may draw a diagram if you wish. … …[1]

8 0653/61/O/N/16 © UCLES 2016 (b) The student then moves the pendulum bob to position P and releases it so that it oscillates. She records the time taken for 20 oscillations. Fig. 3.3 shows the reading on the stopwatch. 00 : 30 . 98 Fig. 3.3 Record in Table 3.1 the reading on the stopwatch to three significant figures. [1] Table 3.1 lA / cm time for 20 oscillations / s period T / s T 2 / s2 50.0 28.4 1.42 2.0 40.0 25.4 1.27 1.6 30.0 22.0 1.10 1.2 20.0 18.0 0.90 0.8 She repeats the procedure described in (b) for lengths lA of 50.0 cm, 40.0 cm, 30.0 cm and 20.0 cm. Her values are shown in Table 3.1. (c) Complete Table 3.1 by calculating the period T of the pendulum and T 2 for the first set of results. Remember that the period is the time for one oscillation.  [2]

9 0653/61/O/N/16 © UCLES 2016 [Turn over (d) On the grid provided, use the information in Table 3.1 to plot a graph of T 2 against lA. Start both axes of your graph from the origin (0, 0). Draw the best-fit straight line. T 2 / s2 lA / cm  [3] (e) Another student suggests that T 2 is directly proportional to lA. State whether your graph supports this suggestion. Give a reason for your answer. … … …[1]

10 0653/61/O/N/16 © UCLES 2016 4 Three students investigate the effect of acid on the growth of some seedlings. Each student sets up three petri dishes. One of the dishes is shown in Fig. 4.1. seeds filter paper Fig. 4.1 Dish A is watered with distilled water. Dishes B and C are watered with dilute acid. The acid used in dish C is more concentrated than the acid used in dish B. The dishes are left in a warm place for a week and then the height of the tallest seedling in each dish is measured to the nearest millimetre. The results for dishes B and C are shown in Table 4.1. Table 4.1 dish seedling height / mm average seedling height / mm student 1 student 2 student 3 A 32 B 14 18 16 C 2 3 1 (a) (i) Measure to the nearest millimetre, the height of each of the seedlings in Fig. 4.2 from the top of the filter paper to the top of the seedling. Record these for dish A for students 2 and 3 in Table 4.1. [2] student 2 student 3 Fig. 4.2 (ii) Calculate the average heights for the seedlings in dishes A, B and C and record these in Table 4.1.  [1]

11 0653/61/O/N/16 © UCLES 2016 [Turn over (b) (i) On the grid below, draw a bar chart to show the data collected by student 1.  [3] (ii) Explain why it would be better to draw a bar chart using the average heights instead of just the results from one student. … …[1] (c) Describe the effect of the acid solutions on the growth of the seedlings. … …[2] (d) State one environmental factor that needs to be kept the same for each of dishes A, B and C. …[1]

12 0653/61/O/N/16 © UCLES 2016 5 A science class is investigating the properties of five different colourless gases. The teacher has given them test-tubes containing the gases V, W, X, Y and Z. Each test-tube contains only one gas. The students carry out different tests on the gases. (a) Test 1. A glowing splint is inserted into a test-tube of each gas. In gas Z the splint relights. Suggest the name of gas Z. …[1] (b) Test 2. Gases V, W and Y are tested to find out if they are acidic, alkaline or neutral. (i) Describe how a student can show that a gas is acidic or alkaline. Include any observations in your answer. … … … …[2] (ii) Describe how a student can show that a gas is neutral. … … …[1]

13 0653/61/O/N/16 © UCLES 2016 [Turn over (c) Test 3. The teacher gives the students a bowl of water. They have no other apparatus except the test-tubes containing the gases. Draw a diagram to show how the students could use only this to find out if the gases are soluble in water. Show clearly what is seen if the gas is soluble in water.  [2] (d) The students find out that gases V and W are soluble in water. They also find out that gas V is alkaline and gas W is acidic. Use these results to suggest a name for the gases V and W. gas V … gas W …  [2] (e) These tests may not be able to identify carbon dioxide gas. Suggest a test to identify carbon dioxide gas and state the observations for a positive result. test … … observations … …  [2]

14 0653/61/O/N/16 © UCLES 2016 6 A student carries out an experiment to compare the electrical resistance of wires L and M. The wires are made of different metal alloys and are each 100 cm long. The student connects wire L into the circuit shown in Fig. 6.1 so that the current and voltage can be measured when the switch is closed. switch power supply variable resistor wire L Fig. 6.1 (a) Complete the symbols for the ammeter and voltmeter in Fig. 6.1. [1] (b) The student closes the switch. She adjusts the variable resistor until there is a small current in wire L. She reads the ammeter and voltmeter and records the readings in Table 6.1. She opens the switch. She repeats the experiment using wire M. Table 6.1 wire current / A voltage / V L 0.80 1.2 M Fig. 6.2 shows the ammeter and voltmeter readings for wire M. Read the current to the nearest 0.05 A and the voltage to the nearest 0.1 V. Record the values in Table 6.1. [2]

15 0653/61/O/N/16 © UCLES 2016 [Turn over A 0 0.5 1.0 V 0 1.0 2.0 Fig. 6.2 (c) Calculate the resistances of wires L and M using the formula shown. resistance = voltage current State the unit of resistance. resistance of wire L = … resistance of wire M = … unit = …  [3]

16 0653/61/O/N/16 © UCLES 2016 (d) Using the circuit in Fig. 6.1, design an experiment to find out how the resistance of a wire changes with its length. In your answer you should include the lengths of the wire to be used, the variables to be controlled and an appropriate circuit diagram. State the results you would record and how you would present your results to show the relationship. … … … … … …[4] 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.

® 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 COMBINED SCIENCE 0653/61 Paper 6 Alternative to Practical October/November 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 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 0653 61 © UCLES 2016 Question Answers Marks 1(a) time and minutes ; observation / appearance ; 2 1(b) iodine (molecules) move into bag / tube ; by diffusion / because they are small enough ; starch and iodine produce blue-black / darker colour ; 3 1(c)(i) (blue-black) colour goes / fades / goes brown ; 1 1(c)(ii) no starch left / no starch-iodine complex ; 1 1(c)(iii) Benedict’s solution ; heat ; yellow / green / orange / red ; 3 Total: 10 Question Answers Marks 2(a)(i) add sodium hydroxide (solution) / NaOH ; green ppt. ; 2 2(a)(ii) add dilute nitric acid / HNO3 ; then add barium nitrate solution / Ba(NO3)2 ; white ppt. ; 3 2(b)(i) hydrogen / H2 ; 1 2(b)(ii) white ppt. ; ppt. dissolves / becomes colourless solution / soluble in excess ; 2

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0653 61 © UCLES 2016 Question Answers Marks 2(c)(i) displacement / redox / cation reduced / it is reduced / Fe2+ goes to Fe / it is replaced by Mg / it is replaced by Mg2+ ; 1 2(c)(ii) exothermic ; 1 Total: 10 Question Answers Marks 3(a)(i) 6.5 ; 1 3(a)(ii) 65 ; 1 3(a)(iii) appropriate precaution (either written or shown on diagram) ; take reading at eye level / use of set square to ensure rule vertical / use of fiducial aid ; max 1 3(b) 31.0 ; 1 3(c) T = 1.55 ; T2 = 2.4 ; 2 3(d) suitable choice of scales (more than half the grid used) ; at least 4 plots correct to ½ small square ; good best-fit straight line with a ruler, omission of anomalous point ; 3 3(e) yes agree (no mark) (straight) line through the origin no disagree (no mark) all points / anomaly not on the (straight) line ; max 1 Total: 10

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0653 61 © UCLES 2016 Question Answers Marks 4(a)(i) dish Seedling height / mm Average seedling height / mm Student 1 Student 2 Student 3 A 32 34 ; 30 ; 32 B 14 18 16 16 C 2 3 1 2 2 4(a)(ii) averages calculated correctly – A = 32, B = 16, C = 2 ; 1 4(b)(i) horizontal axis labelled dish A, B and C ; linear vertical axis labelled height / mm and uses at least half the grid ; all bars correct height ± one half small square ; 3 4(b)(ii) reduces effect of errors / takes account of variations / anomalies accounted for / some results may be error ; 1 4(c) reduced it / shorter/stunted / grows more slowly ; higher concentration has a greater effect ; 2 4(d) same specified environmental conditions, e.g. temperature, light (intensity) ; max 1 Total: 10

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0653 61 © UCLES 2016 Question Answers Marks 5(a) oxygen / O2 ; 1 5(b)(i) litmus ; blue to red gas is acid AND red to blue gas is alkaline ; OR UI / full range indictor / pH indicator ; red / orange / yellow / any pH less than acid AND blue / purple / any pH greater than 7 alkali ; 2 5(b)(ii) gas will not change the colour of red and blue litmus / UI and green or pH 7 ; 1 5(c) diagram showing the inverted test-tube with the open end under water ; water risen into the test-tube ; 2 5(d) gas V = ammonia / NH3 ; gas W = hydrogen chloride / HCl / sulfur dioxide / SO2 ; 2 5(e) add limewater to test-tube and shake ; (limewater goes) white precipitate / milky ; 2 Total: 10

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2016 0653 61 © UCLES 2016 Question Answers Marks 6(a) A in series with the power source AND V in parallel ; 1 6(b) 0.65 (A) ; 1.5 (V) ; 2 6(c) wire L = 1.5 ; wire M (= 1.5 / 0.65 =) 2.3 ; ohms / Ω ; 3 6(d) minimum of 3 lengths ; minimum 10 cm range ; control ONE from material / cross-section / temperature ; graph of resistance against length ; 4 Total: 10