Introduction/Background:

By studying the rate of reaction, valuable information can be gained about how the reaction proceeds- the reaction mechanism. The rate of a reaction is based upon the concentration of reactants and can be expressed mathematically as the "rate law". In order to perform this lab, a reaction between crystal violet (CV+) and sodium hydroxide (OH-) ions must be monitored using a spectroscopic method and applying Beer's Law, A= E l c. The rate law can then be used to relate the rate of the disappearance of reactants or the rate of appearance of products to the concentration of the reactants. Next, the individual reactant reaction orders can be determined by monitoring the change in concentration of one of the reactants or products. The absorption of varying concentrations of both crystal violet and sodium hydroxide will then be measured using a red tide machine. The resulting graph, of ln [CV+] vs. time, can then be used to determine the rate constant (slope).

Purpose:

To determine how fast is "fast" for a chemical reaction.