Search results
Results from the WOW.Com Content Network
Std enthalpy change of vaporization, Δ vap H o: 44.0 kJ/mol Enthalpy change of vaporization at 373.15 K, Δ vap H: 40.68 kJ/mol Std entropy change of vaporization, Δ vap S o: 118.89 J/(mol·K) Entropy change of vaporization at 373.15 K, Δ vap S: 109.02 J/(mol·K) Enthalpy change of sublimation at 273.15 K, Δ sub H: 51.1 kJ/mol Std entropy ...
The specific enthalpy of fusion (more commonly known as latent heat) of water is 333.55 kJ/kg at 0 °C: the same amount of energy is required to melt ice as to warm ice from −160 °C up to its melting point or to heat the same amount of water by about 80 °C. Of common substances, only that of ammonia is higher.
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.
For example, the triple point at 251 K (−22 °C) and 210 MPa (2070 atm) corresponds to the conditions for the coexistence of ice Ih (ordinary ice), ice III and liquid water, all at equilibrium. There are also triple points for the coexistence of three solid phases, for example ice II , ice V and ice VI at 218 K (−55 °C) and 620 MPa (6120 atm).
However, heating 0 °C ice to 20 °C requires additional energy to melt the ice. We can treat these two processes independently and using the specific heat capacity of water to be 4.18 J/(g⋅K); thus, to heat 1 kg of ice from 273.15 K to water at 293.15 K (0 °C to 20 °C) requires:
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
For a liquid–gas transition, is the molar latent heat (or molar enthalpy) of vaporization; for a solid–gas transition, is the molar latent heat of sublimation. If the latent heat is known, then knowledge of one point on the coexistence curve , for instance (1 bar, 373 K) for water, determines the rest of the curve.
Table of specific heat capacities at 25 °C (298 K) unless otherwise noted. [citation needed] Notable minima and maxima are shown in maroon. Substance Phase Isobaric mass heat capacity c P J⋅g −1 ⋅K −1 Molar heat capacity, C P,m and C V,m J⋅mol −1 ⋅K −1 Isobaric volumetric heat capacity C P,v J⋅cm −3 ⋅K −1 Isochoric ...