Question

A boy after swimming comes out from a pool covered with a film of water weighing $ 80\, g $ . How much heat must be supplied to evaporate this water? $ (\Delta H_v^{\circ} = 40.79 \,kJ \,mol^{-1}) $

• A. $ 1.61 \times 10^2 \,kJ $
• B. $ 1.71 \times 10^2 \,kJ $
• C. $ 1.81 \times 10^2 \,kJ $
• D. $ 1.91 \times 10^2 \,kJ $

Answer 1

Answer: (C)

$H_v = 40.79 \,kJ \,mol^{-1}$
Number of moles $(n) = \frac{80}{18}$
Heat, $q = nHv$
$ = \frac{80}{18} \times 40.79$
$ = 181.28\,kJ$
$ = 1.81 \times 10^2 \,kJ$