Famous Fugacity Formulae

Values for fugacities are nearly always calculated using one of the five famous fugacity formulae dted in 6.4. Again, these five formulae represent options that we can exploit in solving all kinds of phase separation and chemical reaction problems. The commonly used procedxues for attacking such problems will be developed in Chapter 10, the solution techniques will be described in Chapter 11, and particular examples will be offered in Chapter 12. 

Before we can solve the equilibrium criteria (8.2.18) and (8.2.19) to obtain the saturation curve, we must replace the fugacities with measurables. One way to proceed is to use famous fugacity formula 1 (6.4.1), which connects fugacities to measurables via fugacity coefficients q). Since both vapor and liquid are pure phases and the pressures in each phase are the same, (8.2.19) combined with (6.4.1) reduces to... 

Here Vjy is the stoichiometric coefficient for species i in reaction j and G,- is the chemical potential for component i. To translate (10.3.7) into a computational form, we choose to use fugacities rather than chemical potentials, for then we can exploit the five famous fugacity formulae presented in 6.4. Recall the fugacity is defined in terms of the chemical potential by... 

All phase and reaction equilibrium computations require expressions for the fugaci-ties of all components. The possible expressions are presented in 6.4 as the five famous fugacity formulae (FFF). Here are some general guidelines for choosing from those possibilities. 

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