At the other limit, as the solution becomes dilute in component A, the partial pressure curve turns into the straight line labeled Henry's law in Fig. 8.2. For this functional dependence, Eq (8.5) shows that the activity coefficient must be constant, although not equal to unity. This dilute solution behavior of a constant activity coefficient reduces Eq (8.5) to:

The product of the activity coefficient and the vapor pressure, kHA, is termed the Henry's law constant. Physically, Henry's law behavior in dilute solutions simply reflects the fact that all A molecules are surrounded by B molecules, irrespective of the concentration of A (as long as it is low). In the Henry's law limit for component A, component B obeys Raoult's law.

Exercises that apply the general partial pressure-composition formulas of Eqs (8.5) and (8.6) are part of problems 8.2, 8.10, 8.15, 8.18 and 8.19. In some of these problems, the activity coefficient is expressed by the regular-solution formulas of Eqs (7.42). The remaining exercises involve nonideal solutions with nonregular activity coefficients.

Was this article helpful?

0 0
Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

Get My Free Ebook

Post a comment