Standard Molar Enthalpy Of Formation
What is Standard Molar Enthalpy Of Formation?
The standard molar enthalpy of formation (ΔH°f) is the change in enthalpy when one mole of a compound is formed from its constituent elements in their standard states (pure substance, 1 bar pressure, usually at 298 K). By definition, the standard enthalpy of formation of any element in its standard state is zero. Using Hess's law, the standard enthalpy of any reaction can be calculated as ΔH°rxn = Σ ΔH°f(products) − Σ ΔH°f(reactants).
Key Facts
Frequently Asked Questions
The standard molar enthalpy of formation (ΔH°f) is the change in enthalpy when one mole of a compound is formed from its constituent elements in their standard states (pure substance, 1 bar pressure, usually at 298 K). By definition, the standard enthalpy of formation of any element in its standard state is zero. Using Hess's law, the standard enthalpy of any reaction can be calculated as ΔH°rxn = Σ ΔH°f(products) − Σ ΔH°f(reactants).