K.C.S.E Physics Q & A - MODEL 2007PP1QN17

K.C.S.E Physics Q & A - MODEL 2007PP1QN17

​(a) Define the term specific latent heat of vaporization of a substance
(b) Figure 11 shows the features of a domestic refrigerator. A volatile liquid circulates through the capillary tubes under the action of the compression pump.

(i) State the reason for using a volatile liquid
(ii) Explain how the volatile liquid is made to vaporize in the cooling compartment and to condense in the cooling fins
(iii) Explain how cooling takes place in the refrigerator
(iv) What is the purpose of the double wall?
(c) Steam of mass 3.0 g at 100⁰C is passed into water of mass 400g at 10⁰C. The final temperature of the mixture is T. the container absorbs negligible heat. (Specific latent heat of vaporization of steam = 2260 kJ/ kg, specific heat capacity of water = 4200Jkg^-1K^-1)
(i) Derive an expression for the heat lost by the steam as it condenses to water at temperature T.
(ii) Derive an expression for the heat gained by water
(iii) Determine the value of T

answers