17.0 g of $\mathrm{NH}_3$ completely vapourises at – $33.42^{\circ} \mathrm{C}$ and 1 bar pressure and the enthalpy change in the process is $23.4 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The enthalpy change for the vapourisation of 85 g of $\mathrm{NH}_3$ under the same conditions is ________ kJ.
