The Most Common Observations of Liquid-Phase Activity Coefficients

1 THE MOST COMMON OBSERVATIONS OF LIQUID-PHASE ACTIVITY COEFFICIENTS 

As discussed in Chapter 8, we have no direct measurements of liquid- or gas-phase activity coefficients. We compute them from observed VLE (or other kinds of physical measurements [1, p. 173]) or estimate them from molecular interaction models. To compute them from VLE observations we must make some kind of assumption about the behavior of the gas. At low pressures we normally assume ideal gas behavior, at modest pressures we use the methods shown in Section 9.7, and at high pressures we use the methods in Chapter 10. 

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