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
![](http://info.babylon.com/onlinebox.cgi?rt=GetFile&uri=!!ARV6FUJ2JP&type=0&index=3615)
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.