The reaction rate is the change in the concentration of a reactant or product per unit time, adjusted by the stoichiometric coefficient so that a single rate describes the reaction. It is usually measured as a decrease in reactant concentration or an increase in product concentration over time. The rate generally falls as a reaction proceeds and the reactants are used up.

反应速率是单位时间内反应物或生成物浓度的变化,并按化学计量系数加以调整,使单一速率即可描述整个反应。它通常以一段时间内反应物浓度的减小或生成物浓度的增大来测量。随着反应进行、反应物被消耗,速率一般会下降。