Fugacity and Fugacity Coefficient of Species in Mixture
| |||||||||||||||||||||||||||

The definition of the fugacity of a species in a mixture is parallel to the definition of the pure species fugacity. For an ideal gas mixture the chemical potential is given by eqn. (6.63):
| |||||||||||||||||||||||||||

(6.63) | |||||||||||||||||||||||||||

Or: (at const. T) | (6.120) | ||||||||||||||||||||||||||

But (at const. T) | |||||||||||||||||||||||||||

Thus: | (6.121) | ||||||||||||||||||||||||||

Or: | (6.122) | ||||||||||||||||||||||||||

Using the same idea implicit in eqn. 6.86, we extend eqn. 6.122 to define a similar expression for fugacity of species in a
real mixture: | |||||||||||||||||||||||||||

| (6.123) |