A-Level Chemistry OCR A H432

5.2.2: Enthalpy and entropy

#5.2.2a

explanation that entropy is a measure of the dispersal of energy in a system which is greater, the more disordered a system

#5.2.2b

explanation of the difference in magnitude of the entropy of a system:

(i) of solids, liquids and gases (ii) for a reaction in which there is a change in the number of gaseous molecules

#5.2.2c

calculation of the entropy change of a system, ∆S, and related quantities for a reaction given the entropies of the reactants and products

#5.2.2d

explanation that the feasibility of a process depends upon the entropy change and temperature in the system, TS, and the enthalpy change of the system, ∆H

#5.2.2e

explanation, and related calculations, of the free energy change, ∆G, as: ∆G = ∆HTS (the Gibbs’ equation) and that a process is feasible when ∆G has a negative value

#5.2.2f

the limitations of predictions made by ∆G about feasibility, in terms of kinetics.

5.2.1
Lattice enthalpy
5.2.3
Redox and electrode potentials