| Formula ↕ | Name ↕ | ΔH° (kJ/mol) ↕ | ΔG° (kJ/mol) ↕ | S° (J·mol⁻¹·K⁻¹) ↕ |
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Add reactants and products, set stoichiometric coefficients, and calculate ΔH°rxn, ΔG°rxn, and ΔS°rxn using Hess's law.
This reference table provides standard thermodynamic data at 298.15 K for over 100 common inorganic and organic compounds. The standard enthalpy of formation ΔHf° is the enthalpy change when one mole of a compound is formed from its constituent elements in their standard reference states. The standard Gibbs energy of formation ΔGf° determines the spontaneity of formation and is related to ΔHf° and S° by ΔG° = ΔH° − TΔS°. The standard molar entropy S° is an absolute quantity (unlike ΔHf° and ΔGf° which are defined relative to elements). The reaction calculator uses Hess's law: ΔH°rxn = Σ(n·ΔHf°products) − Σ(n·ΔHf°reactants), and analogously for ΔG° and ΔS°. Data is sourced from NIST and standard undergraduate thermochemistry references, though values may differ slightly between sources due to rounding conventions.