The enthalpy of vaporization, (symbol ), also known as the heat of vaporization or heat of evaporation, is the energy required to transform a given quantity of a substance from a liquid into a gas at a given pressure (often atmospheric pressure).
It is often measured at the normal boiling point of a substance; although tabulated values are usually corrected to 298 K, the correction is often smaller than the uncertainty in the measured value.
The heat of vaporization is temperature-dependent, though a constant heat of vaporization can be assumed for small temperature ranges and for Tr<<1.0. The heat of vaporization diminishes with increasing temperature and it vanishes completely at the critical temperature (Tr=1) because above the critical temperature the liquid and vapor phases no longer co-exist.
Read more about Enthalpy Of Vaporization: Units, Physical Model For Vaporization, Enthalpy of Condensation, Thermodynamic Background, Vaporization Enthalpy of Electrolyte Solutions
Famous quotes containing the word vaporization:
“On the vaporization and the centralization of the Self. All is there.”
—Charles Baudelaire (1821–1867)