Chemical Kinetics
3.0 Rate Law
3.0 Rate Law
The law states that the rate of a reaction is proportional to the concentration of the reactants.
$$\begin{equation} \begin{aligned} Rate \propto {\left( {concentration} \right)^{order}} \\ Rate = k{\left( {concentration} \right)^{order}} \\\end{aligned} \end{equation} $$ where $k$ is rate constant.
Rate constant is a constant value for any particular reaction and only change with temperature and use of catalyst.
Unit of rate constant is $$\begin{equation} \begin{aligned} Rate = k{\left( {concentration} \right)^{order}} \\ k = \frac{{Rate}}{{{{\left( {concentration} \right)}^{order}}}} = \frac{{conc.}}{{time.{{\left( {conc} \right)}^{order}}}} = {\left( {conc.} \right)^{1 - order}}{\left( {time} \right)^{ - 1}} \\\end{aligned} \end{equation} $$
Therefore, we can say that rate of a reaction decreases with passage of time.
