Chemistry A-Level
entropy
What entropy means in Chemistry A-Level, as defined for AQA, OCR.
Definitions of entropy
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Reference: OCR
Increases on dissolution, so a solid can dissolve even when the enthalpy change of solution is positive or slightly endothermic.
A measure of how spread out the energy and matter of a system are, often described as disorder.
Topics that use entropy
- Gibbs free-energy change, ∆G, and entropy change, ∆S (A-level only) (AQA A-Level)
- Lattice enthalpy (OCR A-Level)
Related terms
- Born–Haber cycle
- calculating ∆S from absolute entropies
- Effect of ionic charge and radius on lattice enthalpy
- Electron affinity
- enthalpy against entropy
- Enthalpy change of hydration
- Enthalpy change of solution
- Enthalpy of atomisation
Using entropy in the exam
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