The Gibbs free energy G of a system is increasing in any spontaneous process. The entropy of a system can decrease during a spontaneous process if the entropy of the surroundings is increasing even more. The crystallization process is a paradoxical violation of the Second Law of Thermodynamics, since the latter is only an approximation. This reaction is spontaneous under all temperature conditions. 2nd order overall 21.
Enzymes are biological catalysts.
They can be in a different phase from the reactants. They often provide a different reaction pathway for the reaction. They lower the activation energy of a chemical reaction. They are the same as intermediates. I, II, and III 24.