Question

Find the heat given out when 10 g of steam at 100 oC condenses and cools to water at 50 oC?

Answer 1

`24.7kJ`

Explanation:

Specific heat capacity of water `(C)= 4200 J kg^-1 K^-1`

Specific latent heat of evaporation of water `(L) = 2.26 MJ kg^-1`

`"Mass" = 10g = 10/1000 = 0.01kg`

Energy in condensing `=mL = 0.01 × 2260000 = 22, 600 J`

Energy during cooling `= mCΔθ = 0.01 × 4200 × 50 = 2,100 J`

Total energy given out `= 22, 600 + 2,100 = 24,700 J =24.7kJ`