Calculateur d'Énergie de Liaison — Formule
## Enthalpy Change of Reaction
### Formula
**ΔH°rxn = Σ ΔHf°(products) − Σ ΔHf°(reactants)**
Where:
- **ΔH°rxn** = standard enthalpy of reaction
- **ΔHf°** = standard enthalpy of formation
Negative ΔH means exothermic (releases heat). Positive ΔH means endothermic (absorbs heat).
### Formula
**ΔH°rxn = Σ ΔHf°(products) − Σ ΔHf°(reactants)**
Where:
- **ΔH°rxn** = standard enthalpy of reaction
- **ΔHf°** = standard enthalpy of formation
Negative ΔH means exothermic (releases heat). Positive ΔH means endothermic (absorbs heat).
Exemple Résolu
Combustion of methane: products ΔHf° sum = -890 kJ, reactants ΔHf° sum = -75 kJ.
- ΔH°rxn = Σ ΔHf°(products) - Σ ΔHf°(reactants)
- ΔH°rxn = -890 - (-75)
- ΔH°rxn = -890 + 75
- ΔH°rxn = -815 kJ (exothermic)