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Hess's Law Calculator

Combine known reaction enthalpies — reversed steps flip signs; multiplied steps scale ΔH.

Calculator

Results update as you type. Every step of the working is shown below.

Examples:

Negative multiplier reverses the step.

Result

Enter values above — the answer appears here instantly, with full working.

Formula used

ΔH_target = Σ kᵢ · ΔHᵢ

Every result substitutes your values into this relation step by step above.

Assumptions

  • Steps sum to the overall target equation (species must cancel).
  • Enthalpies are state functions — path independent.

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