What is the relationship between enthalpy of condensation and enthalpy of vaporization?

The relationship between the enthalpy of condensation and the enthalpy of vaporization is defined by the principle of thermodynamic processes involving phase changes. When a substance vaporizes, it absorbs energy, and this process is associated with a positive enthalpy of vaporization. Conversely, when a substance condenses, it releases energy, leading to a negative enthalpy change, referred to as enthalpy of condensation.

The key aspect here is that the magnitude of energy involved in these two processes is the same, but their signs differ due to the direction of the heat transfer. Thus, the enthalpy of vaporization is positive, indicating energy absorption, while the enthalpy of condensation is negative, indicating energy release. Therefore, the correct relationship is that they are equal in magnitude but opposite in sign, which accurately captures their thermodynamic connection.