State the meaning of specific latent heat.
A student finds the specific latent heat of vaporisation of a liquid using the apparatus shown in Fig. 3.1. The heater is turned on. Once the liquid is boiling at a steady rate, the balance reading is recorded at 2.0 minute intervals. After 10 minutes, the current in the heater is lowered and the balance readings are then taken for another 12 minutes.
Between time $0$ and time $10.0$ minutes, the mass of liquid evaporated is $56\,\text{g}$. Use Fig. 3.3 to determine the mass of liquid evaporated from time $12.0$ minutes to time $22.0$ minutes.
Explain why, even though the heater power is altered, the rate at which thermal energy is lost to the surroundings may be taken as constant.
Determine a value for the liquid’s specific latent heat of vaporisation $L$.
Calculate the rate at which thermal energy is passed to the surroundings.