Standard Enthalpy of Formation
| Formula / Notation | ΔHf°: elements(standard state) → compound; ΔH°rxn = ΣΔHf°(products) - ΣΔHf°(reactants) |
|---|---|
| Also Known As | Standard heat of formation, ΔHf°, molar enthalpy of formation |
What is Standard Enthalpy of Formation?
The enthalpy change when one mole of a compound is formed from its elements in their standard states at 298 K. Symbol: ΔHf°. Elements in their standard state have ΔHf° = 0 by definition. Used with Hess's law to calculate reaction enthalpies.
Formula & Notation
Other Names / Synonyms: Standard heat of formation, ΔHf°, molar enthalpy of formation
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The enthalpy change when one mole of a compound is formed from its elements in their standard states at 298 K. Symbol: ΔHf°. Elements in their standard state have ΔHf° = 0 by definition. Used with Hess's law to calculate reaction enthalpies.
Standard enthalpies of formation are used via Hess's law to calculate reaction enthalpies. They are used in thermodynamic tables for engineering and scientific calculations. Formation enthalpies guide the selection of energetically efficient synthesis routes.
Compounds with large negative enthalpies of formation are very stable, while those with large positive values may be unstable or explosive. This data guides safe handling of energetic materials.
The formula or notation for Standard Enthalpy of Formation is: ΔHf°: elements(standard state) → compound; ΔH°rxn = ΣΔHf°(products) - ΣΔHf°(reactants)