Explanation

The geometric expression of the relationship between environmental constraints (such as temperature and pressure), stable phase state, phase composition and thermodynamics variables (such as chemical potential, molar enthalpy, molar entropy, etc.) after each phase in the rest system reaches equilibrium under given conditions, that is, the system state pavilion under equilibrium conditions. Common examples include the temperature pressure diagram of the unit system, the temperature composition diagram of the binary system under the condition of equal pressure, the isothermal cross section pavilion formed between any two components under the conditions of the ternary system, and the phase pavilion forms such as the chemical composition diagram, the temperature molar entropy diagram, and the pressure molar enthalpy diagram. It can indicate the conditions for the existence of various phase of substances and the relationship between the equilibrium coexistence of various phases; The possible configurations of substances under different conditions, as well as the possible transformation directions and limits of various configurations when conditions change are given.

Classification