OpenStax Chemistry 2e
The rate laws far relate the and the of reactants. We can also determine a second form of each rate law that relates the concentrations of reactants and . These are called integrated rate laws. We can use an integrated rate law to determine the amount of reactant or product present after a period of time or to estimate the time required for a reaction to proceed to a certain extent. For example, an integrated rate law is used to determine the length of time a radioactive material must be stored for its radioactivity to decay to a safe level.
Using calculus, the differential rate law for a chemical reaction can be integrated with respect to time to give an equation that relates the amount of reactant or product present in a reaction mixture to the elapsed time of the reaction. This process can either be very straightforward or very complex, depending on the complexity of the differential rate law.
The of a reaction (t1/2) is the time required for one-half of a given amount of reactant to be consumed. In each succeeding half-life, half of the remaining concentration of the reactant is consumed.
Below is a picture summary of rate laws:
Flowers, P., Theopold, K., Langley, R., & Robinson, W. R. (2019). Chemistry 2e. Houston, Texas: OpenStax. Accessed for free at https://openstax.org/books/chemistry-2e/pages/1-introduction