Beer-Lambert Law and Rates of Reaction?

Question

I just did a lab to find the rate of reaction of iron and iodine (order of reaction, etc.). However, how would I use the Beer-Lambert law and a standard iodine solution to calculate "k"?

I realize you cannot determine "K" directly from the BL law, but how could I use it to realte BL and the rate law?

Answer 1

k (the reaction rate) is not determined from the Beer-Lambert law. The Beer-Lambert law allows you to measure the concentration of a species by measuring the absorbancy at a particular wavelength. You would first need to determine the molar absorbancy coefficient using a series of standard solutions.

Answer 2

Use your standard iodine solution, and other solutions made from it by a known amount of dilution, to get your "calibration graph" of A as a function of iodine concentration.

Use this graph to convert your measured values of A during the experiment to values of iodine concentration.

Then you can work out the kinetics, including the value of k, by seeing how the iodine concentration varied over time.