For water Δ_vap H =41 kJ mol^-1 at 373 K and 1 bar pressure. Assuming that water vapour is an ideal gas that occupies a much larger volume than…

For water $\displaystyle \Delta_{\text {vap }} \mathrm{H}=41 \mathrm{~kJ} \mathrm{~mol}^{-1}$ at $\displaystyle 373$ K and $\displaystyle 1$ bar pressure. Assuming that water vapour is an ideal gas that occupies a much larger volume than liquid water, the internal energy change during evaporation of water is \_\_\_\_ $\displaystyle \mathrm{kJ} \mathrm{mol}^{-1}$. [Use : $\displaystyle \mathrm{R}=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$ ]