What are the relative contributions of the various terms in the gamma/phi expression for VLE? One way to address the question is through calculation of the activity coefficients for a single binary VLE data point via Eq. (14.1):

Term (A) is the value that would follow from modified Raoult's law; term (B) accounts for vapor-phase nonidealities; term (C) is the Poynting factor [see Eq. (11.44)]. Use the single-point data below for the butanenitrile(l)/benzene(2) system at 318.15 K to evaluate all terms for i = 1 and i = 2. Discuss the results.
VLE Data: P = 0.20941 bar, x1 = 0.4819, y1 =0.1813
Anciliaiy data: P1sat = 0.07287 bar, P2sat = 0.29871 bar
B11 = -7, 993 cm3 mol-1, B22 = -1247 cm3 mol-1,
B12 = -2089 cm3 mol-1, V11 = 90 cm3 mol-1, V12 = 92 cm3 mol-1€ƒ

Transcribed Image Text:

rsat УР Yi = t; P sat sat fi (C) (A) (B)