How to use the standard enthalpy of reaction calculator
Compute ΔH° from enthalpies of formation. Enter σ products (ν·δhf), σ reactants (ν·δhf) in the fields above; the reaction enthalpy is computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- P — Σ products (ν·ΔHf) (kJ/mol)
- R — Σ reactants (ν·ΔHf) (kJ/mol)
Worked example
With σ products (ν·δhf) = -1560 kJ/mol, σ reactants (ν·δhf) = -1411 kJ/mol, the calculator gives reaction enthalpy ≈ -149 kJ/mol.
Frequently asked questions
What is the formula for the standard enthalpy of reaction calculation?
Reaction enthalpy (kJ/mol) = P-R. Here P is σ products (ν·δhf) (kJ/mol), R is σ reactants (ν·δhf) (kJ/mol).
What inputs do I need for the standard enthalpy of reaction calculator?
You need σ products (ν·δhf) in kJ/mol, σ reactants (ν·δhf) in kJ/mol. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.