The tabulated thermochemical properties of a substance are often given in JANAF (joint, army, navy, air force) tables. NIST contains are a large database of JANAF tables for many substances. Consider the JANAF table for methane (CH4). The table contains the constant pressure heat capacity ($$C_P$$), standard state entropy ($$S^\circ$$), standard state Gibbs energy ($$G^\circ$$), standard state enthalpy ($$H^\circ$$), standard state enthalpy of formation ($$\Delta_fH^\circ$$), standard state Gibbs energy of formation ($$\Delta_fH^\circ$$), equilibrium constant of formation expressed as a log value ($$\log(K_f)$$). $$G^\circ$$ and $$H^\circ$$ are expressed relative to the standard molar enthalpy at 298.15 K, $$H^\circ(298.15\;\text{K})$$.