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| Phase Diagrams | |||||||||||||
| ·
The
phase equilibrium idea can be generalized to a system with C components
containing P phases to yield the Gibbs Phase Rule.
· The number of degrees of freedom of a system is determined by the number of variables describing the system and the number of constraints linking these variables. · For P phases in equilibrium there are (P - 1) distinct pairs of phases that obey the chemical potential constraint for each of their C components. This gives C (P - 1) constraints from the requirement of phase equilibrium. · Matter is also conserved, and the mole fractions of the components in each of the P phases must sum to unity. This gives P constraints due to the chemical compositions of the phases. · The total constraints experienced by the system are: Total Constraints ={C(P - 1) + P} |
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