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For many substances, the formation reaction may be considered as the sum of a number of simpler reactions, either real or fictitious. The enthalpy of reaction can then be analyzed by applying Hess' law, which states that the sum of the enthalpy changes for a number of individual reaction steps equals the enthalpy change of the overall reaction.
Std enthalpy change of formation, Δ f H o liquid: −238.4 kJ/mol Standard molar entropy, S o liquid: 127.2 J/(mol K) Enthalpy of combustion Δ c H o: −715.0 kJ/mol Heat capacity, c p: 70.8–90.5 J/(mol K) (at −97.6 to 64.7 °C) [5] 79.9 J/(mol K) at 20 °C Gas properties Std enthalpy change of formation, Δ f H o gas: −201.3 kJ/mol ...
Most computerized databases will create a table of thermodynamic values using the values from the datafile. For MgCl 2 (c,l,g) at 1 atm pressure: Thermodynamic properties table for MgCl 2 (c,l,g), from the FREED datafile. Some values have truncated significant figures for display purposes. The table format is a common way to display ...
Std enthalpy change of fusion, Δ fus H o +4.9 kJ/mol Std entropy change of fusion, Δ fus S o +31 J/(mol·K) Std enthalpy change of vaporization, Δ vap H o +42.3 ± 0.4 kJ/mol [4] Std entropy change of vaporization, Δ vap S o: 109.67 J/(mol·K) Molal freezing point constant: −1.99 °C kg/mol Solid properties Std enthalpy change of ...
The standard Gibbs free energy of formation (G f °) of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 bar of pressure and the specified temperature, usually 298.15 K or 25 ...
The enthalpy of formation of one mole of ethane gas refers to the reaction 2 C (graphite) + 3 H 2 (g) → C 2 H 6 (g). Standard enthalpy of hydrogenation is defined as the enthalpy change observed when one mole of an unsaturated compound reacts with an excess of hydrogen to become fully
The enthalpy of solution is most often expressed in kJ/mol at constant temperature. The energy change can be regarded as being made up of three parts: the endothermic breaking of bonds within the solute and within the solvent, and the formation of attractions between the solute and the solvent. An ideal solution has a null enthalpy of mixing.
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