State what is meant by specific latent heat.

1. (a)State what is meant by specific latent heat.[2]
2. (b)(i)A student determines the specific latent heat of vaporisation of a liquid using the apparatus illustrated in [Figure 3.1]. The heater is switched on. When the liquid is boiling at a constant rate, the balance reading is noted at 2.0 minute intervals. After 10 minutes, the current in the heater is reduced and the balance readings are taken for a further 12 minutes. The readings of the ammeter and of the voltmeter are given in [Figure 3.2]. The variation with time of the balance reading is shown in [Figure 3.3]. From time 0 to time 10.0 minutes, the mass of liquid evaporated is 56 g. Use Fig. 3.3 to determine the mass of liquid evaporated from time 12.0 minutes to time 22.0 minutes. mass = ........................................................... g[1]
3. (b)(ii)Explain why, although the power of the heater is changed, the rate of loss of thermal energy to the surroundings may be assumed to be constant.[1]
4. (b)(iii)Determine a value for the specific latent heat of vaporisation L of the liquid. L = ........................................................... Jg⁻¹[4]
5. (b)(iv)Calculate the rate at which thermal energy is transferred to the surroundings. rate = ........................................................... W[2]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.