Cambridge IGCSE Science - Combined 0653 — 2018 Oct/Nov Paper 5 · Variant 1

1 You are going to investigate a leaf. (a) In the box, make a large detailed pencil drawing of the leaf. [3] (b) (i) Measure the longest length of the leaf, not including any stalk. Record this length in millimetres to the nearest millimetre. length of leaf = ................................................ mm [1] (ii) Draw a line to show this longest length on your drawing. Measure and record the length of this line, in millimetres, to the nearest millimetre. length on drawing = ................................................ mm [1] (iii) Use your measurements from (b)(i) and (b)(ii) to calculate the magnification of your drawing. magnification = ...................................................... [1] (c) (i) Describe in detail the steps involved to test the leaf for starch. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[3] (ii) State the observation for a positive result. .......................................................................................................................................[1]

Mark scheme: 1(a) continuous outline ; detail e.g. vein ; length of leaf drawn 70 mm or more ; 3 1(b)(i) value entered to nearest mm ; 1 1(b)(ii) measurement from drawing correct ; 1 1(b)(iii) correct calculation of magnification ; 1 1(c)(i) hot (water / alcohol) ; alcohol ; iodine (solution) ; 3 1(c)(ii) blue-black ; 1

More questions on Photosynthesis

2 You are going to investigate the temperature changes when solid H reacts with solution J. (a) (i) Use the thermometer to measure the temperature T of solution J. Record, in Table 2.1, this value to the nearest 0.5 °C for time = 0. [1] Table 2.1 time / min temperature T / °C 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 (ii) • Place all of solid H into the plastic cup which should be supported in a beaker. • Measure 25 cm3 solution J using the measuring cylinder. • Add the measured volume of solution J to the solid H in the plastic cup. • Start the stopclock. • Stir the mixture thoroughly. • Continue stirring and measure the temperature of the mixture every half minute for four minutes. • Record, in Table 2.1, these values to the nearest 0.5 °C. After the final reading, record in Table 2.2 the appearance of the solid and the solution. [4] Table 2.2 observations solid H solution J before the reaction grey blue after the reaction (b) (i) Use the data in Table 2.1 to estimate the maximum rise in temperature, ΔT, of the mixture during the reaction. ΔT = ................................................. °C [1] (ii) Explain why the value in (b)(i) is only an estimate. ........................................................................................................................................... .......................................................................................................................................[1] (iii) Suggest how you could improve the procedure in (a)(ii) to achieve a more accurate value of the maximum rise in temperature for this experiment without modifying the apparatus or chemicals. ........................................................................................................................................... .......................................................................................................................................[1] (c) Calculate the energy E released in this reaction using the equation shown: E = volume of solution J × 4.2 × ΔT Give your answer to two significant figures. E = ........................................... joules [2]

Mark scheme: 2(a)(i) temperature for t = 0 to nearest 0.5 °C ; 1 2(a)(ii) all readings entered ; maximum by 2.0 min / SV time plus 0.5 min AND only one maximum ; observations solid H solution J (after the reaction) brown / darker grey / black ; colourless / paler blue / grey ; 4 Question Answer Marks 2(b)(i) correct rise in temperature ; 1 2(b)(ii) temperature could have been higher between readings ; 1 2(b)(iii) take readings more frequently (than every 0.5 min) / plot a graph and draw best-fit line ; 1 2(c) use 25 × 4.2 × (b)(i) ; correct answer to 2 sf ; 2

More questions on Experimental design

3 You are going to use a spring to determine the acceleration g due to gravity. (a) Measure the unstretched length l0 of the spring to the nearest millimetre. Do not include the loops at the end of the spring in your measurement. l0 = ............................................... mm [1] (b) Attach the spring to the clamp as shown in Fig. 3.1. clamp spring mass bench Fig. 3.1 • Hang a 200 g mass on the spring. • Measure the stretched length l1 of the spring. • Record your value in Table 3.1. • Calculate the extension e of the spring produced by the mass. Use the equation shown: e = l1 − l0 • Record your value in Table 3.1 on page 8. [1] Table 3.1 stretched time for extension period mass m / g length 20 oscillations T2 / s2 e / mm T / s l1 / mm t / s 200 300 400 500 (c) Pull the mass down a small distance and release it. The mass oscillates up and down. The period T of the oscillations is the time taken for one oscillation. One oscillation is one complete up-motion and one complete down-motion of the mass, as shown in Fig. 3.2. up highest position one rest position oscillation lowest position down Fig. 3.2 (i) Measure the time t taken for 20 oscillations. Record this time in Table 3.1. [1] (ii) Repeat (b) and (c)(i) for masses of 300 g, 400 g and 500 g. [1] (iii) Use your answers from (c)(i) and (c)(ii) to calculate the period T (the time for one oscillation) for each of the masses. Record, in Table 3.1, your values of T. [1] (iv) Calculate the values of T2. Record, in Table 3.1, your answers to two significant figures. [1] (d) (i) On the grid provided, plot a graph of T2 (vertical axis) against e. [1] (ii) Draw the best-fit straight line. [1] 1.2 1.0 0.8 T 2 / s 2 0.6 0.4 0.2 40 80 120 160 200 240 e / mm (iii) Calculate the gradient of your line. gradient = ...................................................... [1] (iv) Use your answer to (d)(iii) and the equation shown to determine a value for the acceleration g due to gravity. 0.0395 g = gradient g = ............................................. m / s2 [1]

Mark scheme: 3(a) 1 3(b) l1 recorded for m = 200g AND l 1 greater than l0 AND e correctly calculated ; 1 3(c)(i) t value recorded in the table for m = 200 ; 1 3(c)(ii) all t values present AND increasing ; 1 3(c)(iii) all T values correct for t values present ; 1 3(c)(iv) all T2 values correct for T values present ; 1 3(d)(i) 3 plots correct to half a small square ; 1 3(d)(ii) good best-fit straight line judgement ; 1 3(d)(iii) correct calculation ; 1 3(d)(iv) correct calculation of g ; 1

More questions on Physical quantities and measurement techniques