Science & Environment
Hess's Law Enthalpy of Reaction Calculator
Calculate the enthalpy of reaction using Hess's law from the standard enthalpies of formation of products and reactants.
Your inputs
Change any value to update the result instantly.
Enthalpy of reaction ΔH
-300 kJ/mol
Products sum
-400 kJ/mol
Reactants sum
-100 kJ/mol
Reaction type
1 Exothermic
Formula and working
ΔH_rxn = ΣΔHf(products) − ΣΔHf(reactants)
- 1
Collect the inputs
Sum of ΔHf products = -400 kJ/mol; Sum of ΔHf reactants = -100 kJ/mol
- 2
Apply the formula
ΔH_rxn = ΣΔHf(products) − ΣΔHf(reactants)
- 3
Result
Enthalpy of reaction ΔH = -300 kJ/mol
Frequently asked questions
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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