Chemistry A-Level
Hess’ law
What Hess’ law means in Chemistry A-Level, as defined for OCR.
Definition of Hess’ law
Check what you remember
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Reference: OCR
The enthalpy change of a reaction is independent of the route taken, provided the initial and final states are the same.
Topics that use Hess’ law
- Enthalpy changes (OCR A-Level)
Related terms
- ∆H of combustion
- ∆H of formation
- Activation energy
- Approximate estimate
- Average bond enthalpy
- Averaging over gaseous compounds
- Bond breaking and bond making
- Bond enthalpy
Using Hess’ law in the exam
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