The rate of many chemical reactions is dependant on reactant concentration.

If the product and reactant concentrations are at equilibrium then the mass-action ratio will equal the equilibrium constant.

A negative sign is present to indicate the reactant concentration is decreasing.

Order: The order of the reaction controls how the reactant concentration (or pressure) affects reaction rate.

Some reactions, however, have rates that are independent of reactant concentrations.

When reactant concentrations differ from standard conditions, the cell potential will deviate from the standard potential.

Gibbs' key contribution was to formalize the understanding of the effect of reactant concentration on spontaneity.

The reaction rate, r, is generally dependent on the reactant concentration and the rate constant (k).

This is true for many enzyme-catalyzed reactions, provided that the reactant concentration is much greater than the enzyme concentration which controls the rate.

A deposition process that is surface-reaction-limited is primarily dependent on reactant concentration and reaction temperature.