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1st Order Kinetics Plot and Half Life Determination

After applying 2,4-D to turf, an experiment was conducted measuring the concentration of 2,4-D that was present over time. The 2,4-D concentration was 80 ppm on day zero, 45 ppm on day 14, and 6 ppm on day 56.

a. Do a first order kinetic plot to determine the rate constant for the disappearance of 2,4-D.
b. What is the half life for disappearance of 2,4-D in this experiment?

Solution Preview

Chemical kinetics involves 'rate laws' which are mathematical equations that describe the progress of a certain reaction. A rate law expresses the rate as being directly proportional to the rate constant (k) and the concentration of the reactant/s.

First-order kinetics is based on a reaction whose rate depends on the concentration of just one reactant. In a first order reaction the rate is directly proportional to the concentration of one of the reactants. There may be other reactants involved, but their concentrations will ...

Solution Summary

This solution shows the detailed steps on how to make a first order kinetic plot from a given set of experimental data including concentration and time. It also shows the important equations needed to construct the plot and calculate the rate constant and half life of a specific substance. An attachment is included so that students will be easily understand how to maximize the use of MS Excel in constructing kinetic plots. The solution can be applied to any branch of chemistry that encompasses chemical kinetics.