Absorption

Absorption in chemistry is a physical or chemical process in which atoms, ions or moleculs enter some bulk phase-gas, liquid,solid material.In many technologically important processes, the chemical absorption is used in place of the physical process, e.g. absorption of carbon dioxide by sodium hydroxide - such processes do not follow the Nernst partition law. In the case of gas absorption, one may calculate its concentration by using e.g. the ideal gas law. Alternatively one may use partial pressure instead of concentration. This is a different process from adsoption since the molecules are taken up by the volume, not by surface.