Rate Laws
The rate of a chemical reaction is, perhaps, its most important
property because it dictates
whether a reaction can occur during a lifetime. Knowing the rate
law, an expression relating
the rate to the concentrations of reactants, can help a chemist adjust the
reaction conditions to get a more
suitable rate. If there are two competing reactions for a single reagent,
one can, knowing the rate
law, favor the exclusive formation of a single product.
To obtain this kind of knowledge about reactions, we will first define what
rate means. We
will then derive the rate law expression. Using the method of initial
rates, we will discuss how to
determine the form and order of the rate law. Next, we will probe rate
laws in depth and
introduce the integrated rate law as an alternative form of the simple
rate law that allows us
another, more simple, experimental method to determine the order of the
rate law. The integrated rate
law will also allow us to determine the half-lives of chemical reactions.
