The molar heat of vaporization of a liquid is the amount of heat to be added to one mole of the liquid at its boiling point to convert into vapor with no change in temperature (Whitten, 2014). Because the heat is added to the system in order to maintain the temperature, vaporization is an endothermic process, therefore ∆Hvaporization is always positive. Heats of vaporization are often expressed in kilojoules rather than joules.
Like many other properties of liquids, heats of vaporization reflect the strengths of intermolecular forces – London forces, present in all molecules, dipole-dipole interactions, which are the result of a polarized structure, and hydrogen bonds, which are the result of a hydrogen atom covalently bonded to a highly electronegative
Like many other properties of liquids, heats of vaporization reflect the strengths of intermolecular forces – London forces, present in all molecules, dipole-dipole interactions, which are the result of a polarized structure, and hydrogen bonds, which are the result of a hydrogen atom covalently bonded to a highly electronegative