Question

The latent heat of vaporisation of water is 2240 J/g. If the work done in the process of vaporisation of 1 g is 168 J, then increase in internal energy is?

Answer 1

Dear Student,

$$\begin{gathered} \mathrm{Latent}\mathrm{heat}\mathrm{of}\mathrm{vaporisation}\mathrm{of}\mathrm{water}\mathrm{in}1\mathrm{g},∆\mathrm{Q}=2240\mathrm{J} \\ \mathrm{Work}\mathrm{done},∆\mathrm{W}=168\mathrm{J} \\ ∆\mathrm{Q}=∆\mathrm{U}+∆\mathrm{W} \\ 2240=∆\mathrm{U}+168 \\ ∆\mathrm{U}=2240-168 \\ ∆\mathrm{U}=2072\mathrm{J} \end{gathered}$$