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Online Chemistry Labs | Learning Objectives

Background:

This experiment allows students to observe directly the effect of matching reactants to a stoichiometric ratio. A quantitative organic reaction is supplied with the two reactants, first in which one is the limiting reagent while the other is in excess. Thin Layer Chromatography is used to observe the compounds present in the flask after reaction. Next the student computes the quantities required for a stoichiometric ratio, and the reaction is carried out. Again using TLC, the reaction products are analyzed. The student is asked to consider various scenarios and to discuss the experimental requirements that make this study effective.

 Synthesis

Learning Objectives:

  1. Become familiar with the principles of thin layer chromatography to identify compounds in a reaction mixture.
  2. Learn how to manipulate TLC equipment and use a capillary tube to sample a reaction mixture.
  3. Use the stoichiometry of a reaction to establish conditions in which one reactant is in excess and the other limiting, as well as how to calculate a  stoichiometric combination ratio. 
  4. Interpret TLC results.
  5. Discuss advantages and limitations of TLC as an analytical method.