Residual function partial molar

These mathematical properties have a simple practical result they ensure that the same relationships can be written among all forms of a thermodynamic function, including molar, total, residual, partial molar, or residual partial molar. 

Partial molar properties play a central role in phase-equilibrium thermodynamics, and it is convenient to broaden their definition to include partial molar residual functions and partial molar excess functions. Hence, we define, analogous to Eq. (1.2-3),... 

To use these values in Eq. 7.18 we need the partial molar volume residual methane- We find its value at 100 psia by plotting the volume residuals at 100 psia as a function of mol fraction, as shown in Figure 7.9, drawing the tangent to the data points at Xmethane = 0.784 and reading its intercept on the 100 mol% methane axis as 0.6 ft /lbmol. 

Figure 4 Normative spinel Iherzolite mineral abundances (wt.%) in batch partial melt extraction residues (0-25%) from fertile peridotite (composition 8, Table 1) as a function of Mg (molar Mg/(Fe + Mg)) at 0.5 GPa, 1 GPa, and 2 GPa, based on the melting model of Kinzler and Grove (1992a, 1993). Normative mineral compositions are calculated using the spinel Iherzolite normative algorithm of Kelemen et ai, (1992).

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