Chemical Kinetics

In this experiment you will find the rate law and rate constant of a chemical reaction.


Answer in writing:

  1. What are the limitations of the Beer-Lambert law? What are the upper and lower concentration limits?
  2. How will the Beer-Lambert's plot appear if the concentration is above the linear region? Why does this deviation occur? Remember: The graph axes are absorbance (y-axis) and concentration (x-axis)
  3. Why is the iodination of acetone independent of the iodine concentration, according to the presented mechanism?
  4. For systems with reaction orders of 0, 1, and 2 in which ε = 100 M-1cm-1 and l = 2 cm
    1. Plot the concentration as a function of time, for an initial concentration of 10 mM.
    2. How will the Beer-Lambert's plot change if the concentration is doubled?
    3. How will the Beer-Lambert's plot change if the molar extinction coefficient, ε, is doubled?
  5. It was found that the reaction A + BC is of the first order in both A and B. What will happen to the reaction rate if the concentrations of A and B are doubled?
  6. The reaction SO2Cl2(g) → SO2(g) + Cl2(g) is a first-order reaction, with a reaction rate of k = 2.2·10-5 sec-1 at 320°C. How much of the SO2Cl2 will be decomposed after 90 minutes at this temperature?
  7. Why can't you use a plastic cuvette in this experiment?

What you should know before the experiment:

  1. How does the spectrometer work and what are its components? What are the parameters you can change in order to control the resolution? What are the advantages and disadvantages of changing each of these parameters?
  2. Understand the mechanism of the acetone iodination reaction and find the expected reaction rate in the literature. What assumptions are made when analyzing this reaction?
  3. If a reaction has an order of 0, 1 or 2, what does it mean? How will the concentration depend on time for reactions of each of these orders?
  4. Understand the rate equation and the relationship between K at equilibrium to k1, k2 and the reaction rate.