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One exception is phosphorus, for which the most stable form at 1 bar is black phosphorus, but white phosphorus is chosen as the standard reference state for zero enthalpy of formation. [2] For example, the standard enthalpy of formation of carbon dioxide is the enthalpy of the following reaction under the above conditions:
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 °C).
The isobaric change in enthalpy H above the common reference temperature of 298.15 K (25 °C) is called the high temperature heat content, the sensible heat, or the relative high-temperature enthalpy, and called henceforth the heat content.
Most hydrogen chloride is consumed in the production of hydrochloric acid. It is also used in the production of vinyl chloride and many alkyl chlorides. [13] Trichlorosilane, a precursor to ultrapure silicon, is produced by the reaction of hydrogen chloride and silicon at around 300 °C. [18] Si + 3 HCl → HSiCl 3 + H 2
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 ...
Std enthalpy of formation Δ f H o solid: −408.27 kJ/mol Standard molar entropy S o solid: 59.33 J/(mol K) Heat capacity c p: 47.99 J/(mol K) Liquid properties Std enthalpy of formation Δ f H o liquid: −390.76 kJ/mol Standard molar entropy S o liquid? J/(mol K) Heat capacity c p? J/(mol K) Gas properties Std enthalpy of formation Δ f H o ...
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 saturated.
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