• # question_answer 55)   18.0 g of water completely vaporises at $100{}^\circ C$and 1 bar pressure and the enthalpy change in the process is$40.79\text{ }kJ\text{ }mo{{l}^{-1}}$. What will be the enthalpy change for vaporizing two moles of water under the same conditions? What is the standard enthalpy of vaporisation for water?

$\Delta H_{vap}^{{}^\circ }=+40.79kJ\,mo{{l}^{-1}}$ Enthalpy of vaporisation for two moles of water $=2\times 40.79kJ=81.58kJ$