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Temperature-dependency of the heats of vaporization for water, methanol, benzene, and acetone. In thermodynamics, the enthalpy of vaporization (symbol ∆H vap), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy that must be added to a liquid substance to transform a quantity of that substance into a gas.
The Shimansky equation describes quite well the heat of vaporization for a wide variety of liquids. For chemical compounds that belong to the same class (e.g. alcohols) the value of ratio remains constant. For each such class of liquids, the Shimansky equation can be re-written in a form of
Latent heat (also known as ... then the vapor's latent energy absorbed during evaporation is released as the ... The modern value for the heat of fusion of ice would ...
In thermodynamics, Trouton's rule states that the (molar) entropy of vaporization is almost the same value, about 85–88 J/(K·mol), for various kinds of liquids at their boiling points. [1] The entropy of vaporization is defined as the ratio between the enthalpy of vaporization and the boiling temperature.
J.A. Dean (ed.), Lange's Handbook of Chemistry (15th Edition), McGraw-Hill, 1999; Section 6, Thermodynamic Properties; Table 6.4, Heats of Fusion, Vaporization, and Sublimation and Specific Heat at Various Temperatures of the Elements and Inorganic Compounds
Substituting into the Clapeyron equation =, we can obtain the Clausius–Clapeyron equation [8]: 509 = for low temperatures and pressures, [8]: 509 where is the specific latent heat of the substance. Instead of the specific, corresponding molar values (i.e. L {\\displaystyle L} in kJ/mol and R = 8.31 J/(mol⋅K)) may also be used.
is the heat flux from the gas to the droplet surface (J.s −1) is the latent heat of evaporation of the species considered (J.kg −1) Analytical expressions for the droplet vaporization rate, ˙, and for the heat flux are now derived. A single, pure, component droplet is considered and the gas phase is assumed to behave as an ideal gas.
The amount of energy required for a phase change is known as latent heat. The "cooling rate" is the slope of the cooling curve at any point. Alloys have a melting point range. It solidifies as shown in the figure above. First, the molten alloy reaches to liquidus temperature and then freezing range starts.