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The enthalpy of fusion is the amount of energy required to convert one mole of solid into liquid. For example, when melting 1 kg of ice (at 0 °C under a wide range of pressures ), 333.55 kJ of energy is absorbed with no temperature change. The heat of solidification (when a substance changes from liquid to solid) is equal and opposite.
Latent heat is energy released or absorbed by a body or a thermodynamic system during a constant-temperature process. Two common forms of latent heat are latent heat of fusion and latent heat of vaporization . These names describe the direction of energy flow when changing from one phase to the next: from solid to liquid, and liquid to gas.
The Clausius–Clapeyron relation describes a Phase transition in a closed system composed of two contiguous phases, condensed matter and ideal gas, of a single substance, in mutual thermodynamic equilibrium, at constant temperature and pressure. Therefore, [ 7]: 508. Using the appropriate Maxwell relation gives [ 7]: 508 where is the pressure.
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
In some texts, the heats of phase transitions are called latent heats (for example, latent heat of fusion). Molar enthalpy of zinc above 298.15 K and at 1 atm pressure, showing discontinuities at the melting and boiling points. The ΔH°m of zinc is 7323 J/mol, and the ΔH°v is 115 330 J/mol.
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
In thermodynamics, the enthalpy of vaporization (symbol ∆Hvap ), also known as the ( latent) heat of vaporization or heat of evaporation, is the amount of energy ( enthalpy) that must be added to a liquid substance to transform a quantity of that substance into a gas. The enthalpy of vaporization is a function of the pressure and temperature ...
For a fuel of composition C c H h O o N n, the (higher) heat of combustion is 419 kJ/mol × (c + 0.3 h − 0.5 o) usually to a good approximation (±3%), [ 2][ 3] though it gives poor results for some compounds such as (gaseous) formaldehyde and carbon monoxide, and can be significantly off if o + n > c, such as for glycerine dinitrate, C3H6O7N2.