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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 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.
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).
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 ...
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 change of formation, Δ f H o liquid –134.3 kJ/mol Standard molar entropy, S o liquid? J/(mol K) Enthalpy of combustion –473.2 kJ/mol Δ c H o: Heat capacity, c p: 114.25 J/(mol K) Gas properties Std enthalpy change of formation, Δ f H o gas –103.18 kJ/mol Standard molar entropy, S o gas: 295.6 J/(mol K) at 25 °C Heat ...
–86.37 kJ/mol at 25 °C Standard molar entropy, S o liquid: 140.08 J/(mol K) Heat capacity, c p: 81.2 J/(mol K) at 15 °C Gas properties Std enthalpy change of formation, Δ f H o gas –83.68 kJ/mol Standard molar entropy, S o gas: 234.36 J/(mol K) at 100 kPa Enthalpy of combustion, Δ c H o gas –764.0 kJ/mol Heat capacity, c p: 40.70 J ...
All values refer to 25 °C and to the thermodynamically stable standard state at that temperature unless noted. Values from CRC refer to "100 kPa (1 bar or 0.987 standard atmospheres )". Lange indirectly defines the values to be standard atmosphere of "1 atm (101325 Pa)", although citing the same NBS and JANAF sources among others.