TABLE14.1 Various Kinds of Phase Transitions and the Role of Nucleation
Phase change Nucleation? Theoryauseful? Occurs in foods? DtrH¼ Teg¼
Solid?solid Yes No? Transition heatb Transition point
Solid?liquid No or yes — Yes — Melting point
Solid?gas No — Yes — Sublimation point
Liquid?solid “freezing” Yes Yes Yes Heat of fusion Melting point
Liquid?solid “saturation” Yes Yes Yes Heat of dissolution Saturation point
Liquid?liquid “classical”c Yes Yes Rare Heat of dissolution Saturation point
Liquid?liquid “polymers”d Yes or no No Yes — —
Liquid?gas Yes No Yes — Boiling point
Gas?liquid Yes Yes No Heat of evaporation Boiling point
Gas?solid Yes Yes No Heat of sublimation Sublimation point
aTheory as outlined in Section 14.2.
bThe difference between the heats of fusion of the two phases.
cTwo different liquids that are partly miscible (e.g., water and 1-butanol).
dThe separation of an aqueous polymer solution into two aqueous phases.