  The law of mass action is used widely. The law of mass action does not
automatically conserve current, as is clear from mathematics of a simple case,
chosen to illustrate the issues. The law of mass action does not force a series
of chemical reactions to have the same current flow everywhere. Interruption of
far-away current does not stop current everywhere in a series of chemical
reactions, and so does not obey Maxwell equations. An additional constraint and
equation is needed to enforce the global continuity of current flow. The
additional constraint is introduced in this paper in the special case that the
chemical reaction describes spatial movement through narrow channels. In that
case, a fully consistent treatment is possible using a variety of models of
charge movement. The general case must be dealt with by variational methods
that enforce consistency of all the physical laws involved. Variational methods
have only recently been developed to ensure that charge flow is conserved
globally, along with mass, in dissipative systems like ions in solution or
proteins. The Energy Variational Approach EnVarA should allow the development
of more robust models of chemical, biochemical, and biological systems, making
practical devices more easy to design and build. These difficulties arise away
from equilibrium, when current flows, and the law of mass action is applied to
a non-equilibrium situation, different from the systems considered when the law
was originally derived. Non-equilibrium systems are important. Almost all of
biology occurs away from equilibrium. Almost all devices of our technology
function away from equilibrium. I believe robust models and device designs in
the chemical world will not be possible until continuity of current is embedded
in a generalization of the law of mass action using a consistent variational
model of energy and dissipation.
