rate equation

The rate law or rate equation for a chemical reaction is an equation that links the reaction rate with concentrations or pressures of reactants and constant parameters (normally rate coefficients and partial reaction orders). For many reactions the rate is given by a power law such as

where [A] and [B] express the concentration of the species A and B, respectively (usually in moles per liter (molarity, M)). The exponents x and y are the partial reaction orders and must be determined experimentally; they are often not equal to the stoichiometric coefficients. The constant k is the rate coefficient or rate constant of the reaction. The value of this coefficient k may depend on conditions such as temperature, ionic strength, surface area of an adsorbent or light irradiation.