Osmotic pressure proves to be a useful topic for illustrating the disputes brought to bear on the chemistry profession when mathematics was introduced into its discipline. Some chemists of the late 19th century thought that the introduction of mathematics would destroy that "chemical feeling" or "experience" so necessary to the practice of…

Discusses the Donnan Effect by considering three possible cases of membrane equilibrium. (MLH)

An easily constructed apparatus that models the effect of penicillin on the structure of bacterial cells is described. Background information and procedures for using the apparatus during a classroom demonstration are included. (JN)

Discusses the use of an ideal gas model to explain osmotic equilibrium and nonequilibrium flows through an ideal semipermeable membrane. Included are a justification of the relationship between an ideal gas and a dilute solution, a review of the irreversible thermodynamic flow, and some sample applications to physiology. (CC)