Kinetics Trace Lab Report

Abstract To determine the rate law with respect to bleach and blue dye, a series of graphic and algebraic manipulations were done on the data obtained in the kinetic trace experiment in order to determine the different components that made up the rate law. Using absorbance spectroscopy to monitor concentration over time, rate order of the dye was found to be 1st order through the integrated rate law and through the proportionality method; the order of the bleach was also determined to be 1st order. Using this information, the rate constant was determined to be 0.408 M-1S-1, the units indicating that the reaction was a second order . Our overall rate law for the entire reaction was Rate =.408[dye][bleach].

Introduction: The rate law is a mathematical relationship that models the direct proportionality between the rate of a reaction and its reactants, and can be used to predict the rate at any point in time, if the concentration of the reactants is known. The rate is influenced by a variety of factors like concentration, temperature and the addition of a catalyst which changes the reaction mechanism. The rate order, which depicts the effect of the reactant concentrations on the overall rate of the reaction, can only be experimentally determined. One of the methods that can be used in the determination of the rate order is the integrated rate law model, which tries to linearize the concentration and time by fitting it into particular graphical format. Zero order reaction is modeled through concentration v time, 1st order model through ln[A] v time , while second order is modeled through 1/[A]/ linear. The other method known as the proportionality method, determines the rate order of the reactants, by monitoring the change on the rate of the reaction as the initial concentration of the reactants are manipulated. Absorbance spectroscopy is used to monitor concentration as a function of time. Due the transparent nature of the bleach, absorption spectroscopy