An average reaction rate is calculated as the change in the concentration of reactants or products over a period of time in the course of the reaction. An instantaneous reaction rate is the rate at a particular moment in the reaction and is usually determined graphically.
The reaction of compound \rm A forming compound \rm B was studied and the following data were collected:
Time (\rm s) \rm [A] (M)
0. 0.184
200. 0.129
500. 0.069
800. 0.031
1200. 0.019
1500. 0.016
What is the instantaneous rate of the reaction at t=800.~{\rm s}?