Isopiestische

Isopiestische is a term used in thermodynamics and physical chemistry to describe a state or condition where the partial pressures of all components in a mixture are held constant. This concept is particularly relevant when studying phase equilibria, such as vapor-liquid equilibrium. When a mixture is in an isopiestic state, it means that as the composition of the mixture changes, the total pressure also changes in such a way that the individual partial pressures of each constituent remain fixed. This is distinct from an isobaric process where the total pressure is constant, but the partial pressures can vary.

The isopiestic condition implies a specific relationship between temperature, composition, and pressure. For a given mixture, achieving an isopiestic state often involves controlling the temperature and potentially the overall composition to maintain the desired constant partial pressures. Understanding isopiestic conditions is crucial for accurately modeling and predicting the behavior of multi-component systems under various thermodynamic constraints. It helps in designing separation processes and understanding the equilibrium properties of complex mixtures.