91影视

The heat of fusion $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{fus}}\mathbf{)}$ is the heat required to convert one mole of solid to liquid whereas heat of vaporization is the heat required to convert one mole of liquid to gas.

The relative magnitude of the intermolecular forces of attraction is always higher for solids, less for liquids, and almost negligible for gases.

It means more energy is required to overcome these intermolecular forces to convert solid to liquid during the fusion process. On the other hand, to convert liquid to gaseous vapor, comparatively less external energy is required.

Thus, the heat of fusion $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{fus}}\mathbf{)}$is comparatively more than the heat of vaporization $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{vap}}\mathbf{)}$.

Heat of sublimation is the heat required for the conversion of solid form directly into vapor form whereas the vaporization includes the heat required for transformation of liquid phase to the vapor phase.

As the heat of sublimation $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{subl}}\mathbf{)}$ is the sum of heat of fusion $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{fus}}\mathbf{)}$ and heat of vaporization $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{vap}}\mathbf{)}$ and both the process are exothermic in nature, thus the heat of sublimation role="math" localid="1658933687676" $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{subl}}\mathbf{)}$is more than vaporization $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{vap}}\mathbf{)}$.

Heat of vaporization $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{vap}}\mathbf{)}$ is the heat required for the conversion of liquid phase to vapor phase, whereas the heat of condensation $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{cond}}\mathbf{)}$ is the heat released during the formation of vapor phase to the liquid phase.

As the heat exchanged during the physical process depends on the initial and final phase, herein

$\mathbf{Liquid}鈫�\mathbf{Vapor}$

The heat exchange in both the process will be the same, at a constant temperature and pressure thus the magnitude of the vaporization and condensation is the same. But as the processes are endothermic and exothermic respectively, $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{vap}}\mathbf{)}$should be positive and $\mathbf{(}\mathbf{螖}{\mathbf{H}}_{\mathbf{cond}}\mathbf{)}$should be negative.