Assuming the water vapour to be a perfect gas, calculate the internal energy change when 1 mol of water at `100^(@)C` and 1 bar pressure is converted to ice at `0^(@)C`. Given the enthalpy of fusion of ice is 6.00 kJ `"mol"^(- 1)` heat capacity of water is `4.2 J//g^(@)C`
The change take place as follows: