Calculate the constant external pressure required to expand 2 moles of an ideal gas from volume $15 \mathrm{dm}^3$ to $20 \mathrm{dm}^3$ if amount of work done is -600 J .

Calculate the enthalpy of vaporisation of ethanol if 11.5 g of ethanol is completely vaporised by supplying 11.8 kJ of heat.

Calculate the enthalpy change of vaporisation of benzene if 13 gram of benzene vaporised by supplying 5.1 kJ of heat.

Calculate the entropy change of surrounding if 2 moles of $\mathrm{H}_2$ and 1 mole of $\mathrm{O}_2$ gas combine to form 2 moles of liquid water by releasing 525 kJ heat to surrounding at constant pressure and at 300 K .