enthalpy change
What enthalpy change means in Chemistry A-Level, as defined for AQA, OCR.
Definitions of enthalpy change
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Reference: OCR
The heat energy transferred at constant pressure, whose sign shows direction: negative for exothermic, positive for endothermic.
The heat energy change measured under conditions of constant pressure.
Topics that use enthalpy change
- Enthalpy change (AQA A-Level)
- Enthalpy changes (OCR A-Level)
Related terms
- sign of ∆H
- ∆H of combustion
- ∆H of formation
- Activation energy
- Approximate estimate
- Average bond enthalpy
- Averaging over gaseous compounds
- Bond breaking and bond making
Using enthalpy change in the exam
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