Patterns in reaction rate data can often be identified by examining the initial rate
of reaction, the instantaneous rate right at the start of a reaction (FIG. 15.6). The
advantage of examining the initial rate is that the presence of products later in the
reaction may affect the rate; the interpretation of the rate is then quite complicated.
There are no products present at the start of the reaction, and so any pattern
due solely to the reactants themselves is easier to find
the instantaneous rate right at the start of a reaction