# Definition of enthalpy of vaporization

The amount of heat required to vapourize one mole of a liquid at constant temperature and under standard pressure (1 bar) is called its standard enthalpy of vapourization.

The enthalpy of vaporization is often quoted for the normal boiling temperature of the substance.

Suppose, some amount of water is kept inside a perfect thermally conducting container at 1 bar pressure and $$\mathrm 50~^\circ \mathrm{C}$$ within a thermal reservoir of $$\mathrm 50~^\circ \mathrm{C}$$ also. Due to evaporation, slowly liquid will convert to vapours.

After one mole of water evaporates, if we measure the heat energy received by the container from the reservoir, would it be equal to standard enthalpy of vapourization of water at $$\mathrm 50~^\circ \mathrm{C}$$?