The purpose of this lab is to determine how fast is "fast" for a chemical reaction. The area of chemistry that deals with how quickly or slowly reactions take place is called kinetics. The rate of the reaction depends on the concentration of the reactants and can be mathematically expressed as the rate law. If the reaction was bB + cC -> products, then the rate law can be expressed as :
k is the rate constant and b and c are the individual reaction orders for each reactant.
To measure the rate of the reaction, the change of concentration over the change of reactants or products is found using the rate law. the rate of the reaction is always positive. In this lab the concentration of the reaction is monitored in a chemical reaction using a spectroscopic method and using Beer's Law. The chemical reaction is between crystal violet and OH- ions. Crystal violet is a blue color and the OH- ions are colorless. The absorption is attributed to the reactant present in the solution. The "initial rate method" will be used to determine the order of reactants. This is done by measuring the initial rate of the reaction under carefully chosen conditions and then applying the rate equation under two different conditions. This reaction is expected to be a first order reaction. It is important that the results reflect what the expected order of reaction is.