9.6 Free Energy of Dissolution

Just like how finding the enthalpy of a dissolution may be tricky, the same thing applies to the entropy. The change in entropy depends on both the intermolecular forces of the original solid that is being dissolved, the reorganization of the solvent in the dissolved species, and the interactions of the dissolved species with the solvent. All of these processes have a different entropy, which makes it hard to sum their net value. This means that for the AP Chemistry exam, they will usually tell you whether a dissolution is increasing or decreasing in entropy, since it is often ambiguous.