Читать книгу Geochemistry - William M. White - Страница 132

Consider a liquid, water for example, in equilibrium with a gas, the atmosphere for example. Earlier in this chapter, we found that the partial pressure of component i in the gas could be related to the concentration of a component i in the liquid by Henry's law:

(3.10)

where h is Henry's law constant. We can rearrange this as:

(3.94)

Notice that this equation is analogous in form to the equilibrium constant expression (3.88), except that we have used a partial pressure in place of one of the concentrations. A Henry's law constant is thus a form of equilibrium constant used for gas solubility: it relates the equilibrium concentration of a substance in a liquid solution to that component's partial pressure in a gas.