Final answer:
The heat of vaporization is the energy needed to convert a liquid into a vapor. Water has a high heat of vaporization due to hydrogen bonding, which requires a considerable amount of energy to transform liquid water into water vapor.
Step-by-step explanation:
The heat of vaporization refers to the amount of heat per gram or per mole required for a phase change that occurs at the boiling point. It is the energy needed to convert a liquid into a vapor. In the case of water, it has an unusually high heat of vaporization due to the network of hydrogen bonding present between water molecules. This means that a significant amount of energy is required to transform liquid water into water vapor.