Chemical Kinetics
In this experiment you will find the rate law and rate constant of a chemical reaction.
Experimental Procedure
Part 1: Beer-Lambert's Law Validation
In this section you will validate Beer-Lambert's law and calculate the molar absorption coefficient of the iodide ion at several wavelengths.
- Prepare solutions of iodide at a number of different concentrations. You will recieve an Iodine stock solution at a concentration of 0.05 M.
- Obtain the absorption spectrum for each concentration.
- Choose several wavelengths within the range of iodide absorption.
- Plot the absorption at these wavelengths as a function of the concentration. Is the obtained plot linear? If not, is there a regime where the plot is linear?
- Calculate the molar absorption coefficient of the iodide at each selected wavelength.
Part 2: Determination of Optimal Acid:Acetone:Iodide Ratio
Find the ratio of acid to acetone to iodide that will produce a reaction time of 2-3 minutes within the experimental framework. You will recieve a concentrated HCl solution at 32% (w/w) and a 100% w/w solution of acetone.
Part 3: Finding the Reaction Order for Each Component
- Measure the absorption as a function of time. Plot the iodine concentration versus time and determine the reaction rate of the iodination.
- Repeat the previous step with different concentrations of acid, acetone and iodide. Note: take at least 4 points per component.
- Calculate the reaction order for each component.
Part 4: Data Analysis
Using the data from the previous section, calculate the rate constant for the reaction.