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The pressure on a pressure-temperature diagram (such as the water phase diagram shown above) is the partial pressure of the substance in question. A phase diagram in physical chemistry, engineering, mineralogy, and materials science is a type of chart used to show conditions (pressure, temperature, etc.) at which thermodynamically distinct ...
The discontinuity in , and other properties, e.g. internal energy, , and entropy,, of the substance, is called a first order phase transition. [12] [13] In order to specify the unique experimentally observed pressure, (), at which it occurs another thermodynamic condition is required, for from Fig.1 it could clearly occur for any pressure in the range .
A generic phase diagram with unspecified axes; the invariant point is marked in red, metastable extensions labeled in blue, relevant reactions noted on stable ends of univariant lines. This rule is geometrically sound in the construction of phase diagrams since for every metastable reaction, there must be a phase that is relatively stable. This ...
A plot of typical polymer solution phase behavior including two critical points: a LCST and an UCST. The liquid–liquid critical point of a solution, which occurs at the critical solution temperature, occurs at the limit of the two-phase region of the phase diagram. In other words, it is the point at which an infinitesimal change in some ...
In chemistry, the lever rule is a formula used to determine the mole fraction (x i) or the mass fraction (w i) of each phase of a binary equilibrium phase diagram.It can be used to determine the fraction of liquid and solid phases for a given binary composition and temperature that is between the liquidus and solidus line.
By controlling the temperature and the pressure, the system can be brought to any point on the phase diagram. From a point in the solid stability region (left side of the diagram), increasing the temperature of the system would bring it into the region where a liquid or a gas is the equilibrium phase (depending on the pressure).
CALPHAD stands for Computer Coupling of Phase Diagrams and Thermochemistry, a methodology introduced in 1970 by Larry Kaufman, originally known as CALculation of PHAse Diagrams. [1] [2] [3] An equilibrium phase diagram is usually a diagram with axes for temperature and composition of a chemical system. It shows the regions where substances or ...
The phase space can also refer to the space that is parameterized by the macroscopic states of the system, such as pressure, temperature, etc. For instance, one may view the pressure–volume diagram or temperature–entropy diagram as describing part of this phase space. A point in this phase space is correspondingly called a macrostate.