Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2019 May/June Paper 5 · Variant 1

1 You are going to investigate the loss of body temperature from an adult animal and from a baby animal using a large test-tube and a small test-tube to represent the animals. (a) (i) Read through the procedure in part (a)(ii). Complete the heading of the first column of Table 1.1, including units. [1] (ii) Procedure • Use the hot water to fill the large test-tube carefully to the line marked. • Place a thermometer in the hot water in the large test-tube. • When the reading stops rising, record in Table 1.1 the temperature to the nearest 0.5°C of the hot water in the large test-tube for time = 0. • Start the stopclock. • Read and record in Table 1.1 the temperature to the nearest 0.5°C of the water in the large test-tube every minute, for 5 minutes. • Repeat the above procedure using the small test-tube instead of the large test-tube. Use a fresh supply of hot water. Table 1.1 temperature of water in temperature of water in ……………….….….. / …….……… large test-tube / °C small test-tube / °C 0 1 2 3 4 5 [4] (b) (i) On the grid provided, draw and label the axes for a graph of temperature (vertical axis) against time. Choose a scale for the temperature axis suitable to plot all the data in Table 1.1. You do not need to start your temperature axis at 0°C. [2] (ii) On the axes drawn in (b)(i): • plot the points for the large test-tube • draw the smooth curve of best fit and label the line L • using the same axes, plot the points for the small test-tube • draw the smooth curve of best fit for the small test-tube and label the line S. [2] (c) (i) Use your results in Table 1.1 to calculate the drop in temperature of the water over 5 minutes for each test-tube. large test-tube = ...........................................................°C small test-tube = ...........................................................°C [1] (ii) State and explain what the graphs show about the rate of heat loss from the test-tubes. ..................................................................................................................................... [1] (iii) The teacher says that baby animals need more energy from food for each gram of their body mass than adults. Use your answers to (c)(i) and (c)(ii) to explain whether your results support this statement. ........................................................................................................................................... ..................................................................................................................................... [1] [Total: 12]

Mark scheme: 1(a)(i) time and minutes ; 1 1(a)(ii) temperature for large test-tube at time = 0 ; full set of results for large test-tube and temperatures reduce over time ; full set of results for small test-tube and bigger drop over 5 minutes ; reading to nearest 0.5 °C ; 4 1(b)(i) axes labelled including units ; sensible linear scale and uses at least half the space ; 2 1(b)(ii) at least 4 correct plots ± half small square for each line ; two smooth curves of best fit correctly labelled ; 2 1(c)(i) both calculated correctly ; 1 1(c)(ii) greater loss in small test-tube because steeper graph / larger ∆T in same time ; 1 1(c)(iii) expect yes, because small test-tube / the baby has the greater heat loss / loses heat faster ; 1

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2 When acids react with alkalis, heat is given out. These reactions are exothermic. Plan an investigation using a thermometer to compare the amount of heat given out when each of the acids listed reacts with an alkali. hydrochloric acid nitric acid sulfuric acid You are not required to carry out this experiment. Your plan should include: • a suitable named alkali • a description of the apparatus needed and how it is used, including how to reduce heat losses • the readings to be taken • which variables you will keep the same • how you will use the readings to make the comparison. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .................................................................................................................................................... [7] [Total: 7]

Mark scheme: 2 alkali named alkali e.g. sodium hydroxide / potassium hydroxide / limewater / ammonia / ammonium hydroxide etc. ; apparatus and method measuring cylinder / pipette / burette and thermometer ; suitable vessel for reaction and lid / lagging / polystyrene cup ; repeat all three (several times) ; readings initial temperature ; highest / final temperature ; control same volumes / amounts of acids / alkali ; same concentrations of acids / alkali ; same starting temperature use of results calculate rise in temperature for each acid and compare / higher temperature rise means more heat given out ; max 7

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3 You are going to use a pendulum to measure the acceleration of free fall g. A pendulum has been set up in a clamp for you as shown in Fig. 3.1. clamp l bob bench Fig. 3.1 The length l of the pendulum is the distance from the bottom of the clamp to the centre of the pendulum bob. (a) Adjust the string until the length l of the pendulum is 40.0 cm. One complete oscillation of the pendulum is shown in Fig. 3.2. One complete oscillation takes place when the bob swings from x to y and then back to x. x y Fig. 3.2 Give the bob a small sideways displacement, and release it so that it oscillates freely. (i) Measure the time t for 20 complete oscillations. t = ....................................................... s [1] (ii) Calculate the time T for one complete oscillation of the pendulum for l = 40.0 cm. T = ....................................................... s [1] (iii) Calculate T 2. T 2 = ..................................................... s2 [1] (b) The acceleration of free fall g is given by the equation shown. (0.395 × l) g = 2 T Use this equation with l = 40.0 cm to calculate a value for g. Give your answer to three significant figures. g = ................................................ m / s2 [2] (c) Adjust the string until the length l of the pendulum is 80.0 cm. Repeat the procedure in (a)(i), (ii) and (iii) for l = 80.0 cm. t = ............................................................. s T = ............................................................. s T 2 = ........................................................... s2 [1] (d) Use the equation in (b) with l = 80.0 cm to calculate a second value for g. g = ................................................ m / s2 [1] (e) Compare your measured values of g from parts (b) and (d) with the actual value of 9.8 m / s2. State whether or not your values agree with the actual value of g within the limits of experimental error. Justify your answer with reference to your values. ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [1] (f) (i) Using your value for T in (c), calculate the frequency of oscillation for pendulum length l = 80.0 cm using the equation shown. 1 frequency = T ..................................................... Hz [1] (ii) Suggest why it is better experimental practice to use longer lengths of pendulum when performing this experiment. ........................................................................................................................................... ..................................................................................................................................... [1] [Total: 10]

Mark scheme: 3(a)(i) t = 24.5 to 26.5 inclusive s ; 1 3(a)(ii) T = t / 20 ; 1 3(a)(iii) T 2 correct ; 1 3(b) g (calculated and) within the range 8 to 12 ; answer to 3 significant figures ; 2 3(c) full set of values present ; t value greater than in 3(a)(i) ; 1 3(d) g calculated correctly ; 1 3(e) agree, values close enough ; or disagree, difference too large ; 1 3(f)(i) 1 / their value of T from 3(c) ; 1 3(f)(ii) reaction time errors less significant / larger length, measurement errors less significant ; 1

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4 You are provided with a piece of fruit. The fruit has been cut in half and the stone removed. (a) In the box, make an enlarged detailed pencil drawing of the cut surface of the fruit. [3] (b) (i) Measure the diameter of the piece of fruit. Record this length in millimetres to the nearest millimetre. diameter of fruit = .................................................. mm [1] (ii) Draw a line to show the same diameter on your drawing. Measure and record this diameter in millimetres to the nearest millimetre. diameter of drawing = .................................................. mm [1] (iii) Use your measurements to calculate the magnification of your drawing. magnification = ......................................................... [1] (c) (i) A student tests the fruit for the presence of reducing sugar. State the name of the solution he uses to test for reducing sugar. ..................................................................................................................................... [1] (ii) The fruit gives a positive result for the presence of reducing sugar. State a colour that indicates a positive result for the presence of reducing sugar. ..................................................................................................................................... [1] [Total: 8]

Mark scheme: 4(a) clear and continuous outline ; larger than half the box ; detail in centre ; 3 4(b)(i) measurement to nearest mm and smaller than 1(b)(ii) ; 1 4(b)(ii) line drawn and correct measurement to nearest mm ± 2 mm ; 1 4(b)(iii) correct calculation ; 1 4(c)(i) Benedict’s ; 1 4(c)(ii) green / yellow / orange / red ; 1

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5 Notes for use in Qualitative Analysis for this question are printed on page 16. You are going to investigate the use of barium nitrate solution as a reagent in qualitative analysis. You will then identify the cation and anion in the unknown substance H. (a) (i) React aqueous sodium carbonate with dilute nitric acid in a test-tube. In a separate test-tube react aqueous sodium carbonate with barium nitrate solution. Record your results in Table 5.1. [1] Table 5.1 observations reaction with dilute nitric acid reaction with barium nitrate solution aqueous sodium carbonate aqueous sodium sulfate (ii) Repeat (a)(i) using aqueous sodium sulfate instead of aqueous sodium carbonate. Record your results in the next row in Table 5.1. [1] (b) Use of barium nitrate solution on its own does not distinguish between the carbonate ion and the sulfate ion. (i) Use the results in Table 5.1 to explain why this statement is correct. ........................................................................................................................................... ..................................................................................................................................... [1] (ii) State and explain how this problem is overcome in Qualitative Analysis. ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (c) Use Qualitative Analysis to identify the cation and anion in the unknown substance H. Solid H has been dissolved in distilled water to make a solution of H. You may use the following reagents for carrying out the tests on the solution of H. ammonia solution barium nitrate solution litmus papers nitric acid silver nitrate solution sodium hydroxide solution Record all tests, observations and conclusions in Table 5.2. Table 5.2 observations

Mark scheme: 5(a)(i) dilute nitric acid barium nitrate sodium carbonate effervesces / bubbles / fizzes and«>>> >>>«and white ppt; 1 5(a)(ii) dilute nitric acid barium nitrate sodium sulfate no reaction and«>>> >>>«and white ppt.; 1 5(b)(i) both give white ppt. / both give same result ; 1 5(b)(ii) add dilute nitric acid first / add dilute nitric acid ; carbonate will bubble with nitric acid / acid removes carbonate / carbonate will not give ppt. with barium nitrate after acid added first ; 2 5(c) tests observations conclusions add sodium hydroxide solution or ammonia solution ; no ppt ; not Cu2+ / Zn2+ / Fe2+ / Fe3+ ; heat with sodium hydroxide solution ; (red) litmus goes blue ; ammonium / NH4+ ; dilute nitric acid and«>>> >>>«and no reaction ; (not carbonate) add barium nitrate solution and«>>> >>>«and white (ppt) ; sulfate / SO42– ; max 8

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6 You are going to find the spring constant k of a spring. You will then use the spring to measure the mass and density of a stone. The spring constant k of a spring is a measure of the elastic stiffness of the spring. A spring has been set up on a stand for you as shown in Fig. 6.1. clamp spring stand Fig. 6.1 (a) Measure the unstretched length l1 of the spring to the nearest millimetre. Do not include the loops at the end of the spring in your measurement. l1 = .................................................. mm [1] (b) (i) Suspend the 300 g mass on the spring. Measure the stretched length l2 of the spring. Do not include the loops at the end of the spring in your measurement. l2 = .................................................. mm Calculate the extension e of the spring produced by the mass. Use the equation shown. e = l2 – l1 e = .................................................. mm [1] (ii) Calculate the spring constant k of the spring. Use the equation shown. F k = e where F = 3 N (the weight of the 300 g mass). k = .............................................. N / mm [1] (c) It is important to avoid errors when measuring the length of the spring. Describe two ways in which you can avoid these errors. 1 ................................................................................................................................................. ................................................................................................................................................... 2 ................................................................................................................................................. ................................................................................................................................................... [2] (d) Procedure • Remove the 300 g mass from the spring. • Attach the stone provided to the spring. Measure the stretched length lA of the spring and calculate the extension eA of the spring caused by the stone. lA = ........................................................ mm eA = ........................................................ mm [1] (e) Use your answers to (b)(ii) and (d) to calculate the mass m of the stone. Use the equation shown. m = 100keA m = ...................................................... g [1] (f) Procedure • Place the beaker of water under the spring. • Slowly lower the clamp until the stone is completely submerged in water, as shown in Fig. 6.2. clamp spring stand stone water Fig. 6.2 Measure the length lW of the spring and calculate the extension eW of the spring caused by the stone. lW = ........................................................ mm eW = ........................................................ mm [1] (g) Use your answers to (d) and (f) to calculate the density ρ of the stone, using the equation shown. eA ρ = (eA − eW) ρ = .............................................. g / cm3 [2] [Total: 10]

Mark scheme: 6(a) 1 6(b)(i) l 2 recorded and e calculated correctly ; 1 6(b)(ii) correct calculation of k ; 1 6(c) any two from place the ruler close to the spring ; view perpendicularly / view at eye level ; clamp rule vertically ; use a set-square / other fiducial aid ; max 2 6(d) l A recorded and eA correct ; 1 6(e) m calculated correctly ; 1 6(f) eW < eA ; 1 6(g) ρ calculation correct ; value between 2.(0) and 4.(0) ; 2

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