How Kinetic Experiments are Performed

We now turn our attention to the goals of studying kinetics, how kinetic experiments are performed, and how they are analyzed. The study of the kinetics of a reaction is often one of the first experiments that chemists consider when setting out to determine the mechanism of a reaction. However, it is usually just one of the experiments performed, and the information obtained is combined with data collected from many other observations. It is important to note that kinetics does not give a complete picture of a mechanism. The information can only be used to support or refute a particular mechanism, and cannot be used to prove a mechanism. 

In Sections 7.1.4 and 7.1.5 we introduced rates, rate laws, rate constants, kinetic order, and molecularity. You may want to quickly review these sections before proceeding if you are uncomfortable with these terms and concepts. Our discussion here assumes you have a good understanding of these concepts. 

The goal of kinetics is to establish a quantitative relationship between the concentrations of reactants and/or products, and the rate of the reaction. As we will see, this usually entails a separate kinetic study at several different concentrations of a reactant, with the goal of discovering the kinetic order of the reaction with respect to that reactant. A thorough analysis gives the kinetic order for each reactant, which in turn gives the rate law for the reaction. Once the rate law is in hand, one of the several analyses given below is used to determine a rate constant. 

One obvious piece of information that a kinetic experiment yields is the actual rate of the reaction. Is the reaction relatively fast (over in microseconds) or relatively slow (takes days to weeks to go to completion) The rate is expressed as the time dependence of the appearance of product or disappearance of reactant and is a positive number (Eq. 7.2). Determining the concentration of the reactant and / or product as a function of time is the essence of every kinetic experiment. 

What does the order of the reaction tell us about the mechanism How do we determine the rate law of a reaction, and thereby the order of the reaction with respect to each reactant In addition, how do we determine rate constants These are the questions that are of para- 

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