What does the enthalpy of vaporization represent?

The enthalpy of vaporization represents the difference in enthalpy per mole between the gaseous and liquid states. This term quantifies the amount of energy needed to convert a mole of a liquid into a gas at a given temperature and pressure, typically occurring at the boiling point of the liquid. When a substance is vaporized, energy is absorbed to overcome the intermolecular forces that hold the molecules together in the liquid state; thus, it reflects the endothermic process of transitioning from liquid to gas.

The concept is crucial in understanding phase changes and thermodynamic properties of substances, particularly in applications involving heating, cooling, and energy transfer during processes like boiling and condensation.