ChemistryCode 9701
Entropy change, ΔS
What this topic asks you to be able to do
- define entropy, S, as how many different arrangements are possible for the particles in a given system and for their energy
- predict and explain the sign of each entropy change that takes place: (a) while a substance changes state, e.g. melting, boiling and dissolving (and the reverse of each) (b) during a change in temperature (c) in a reaction where the number of gaseous molecules alters
- work out the entropy change, ΔS, of a reaction from the standard entropies, S⦵, of its reactants and of its products, using ΔS⦵ = ΣS⦵ (products) – ΣS⦵ (reactants)