Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Enthalpies of formation refer to the change in enthalpy when one mole of a substance in its standard state is formed from its pure elements under similar conditions.
Related terms
Standard State Conditions: These are reference conditions used for measuring properties related to enthalpy changes such as heat capacity and calorific value. They typically involve pressures at 1 bar or temperatures around 25 degrees Celsius.
Enthalpy Change (∆H): This term represents the total heat content change within a system during a reaction occurring at constant pressure.
Exothermic and Endothermic Reactions: These are types of chemical reactions that either release heat (exothermic) or absorb heat (endothermic), respectively.