Entropy

Entropy = a measure of disorder - the larger the entropy value, the more disordered a substance is

Entropy increases as -

• temperature increases

  • particles gain energy + move further apart

• state changes of solid → liquid or liquid → gas

  • gases have greater entropy than solids or liquids

  • entropy change of vaporisation is much greater than entropy of fusion because gas is more disordered than a liquid or solid

Gibbs Free-Energy can be used to calculate the entropy value

Spontaneous reactions have a NEGATIVE entropy value

To find the specific temperature at which a reaction is feasible ΔG = 0