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Online Chemistry Labs | Learning Objectives

Background:

This experiment allows the student to perform the classic iodine clock kinetics reaction. The student prepares solutions of the various reagents to evaluate the reaction rate dependence on iodide concentration. Students calculate the concentrations of all species and monitor with a timer each reaction's time to observe the appearence of blue starch color. Students perform a linear regression analysis using s log-log plot of rate vs concentration to determine the power of  the iodide term in the rate law. The student discusses various sources of error in the experiment and predicts expected outcomes for new conditions.

 Iodine Clock

Learning Objectives:

  1. Prepare and carry out four trials using the correct combination of available reagent solutions.
  2. Be able to calculate the concentration of each species in each reaction when different additive volumes and initial concentrations are combined.
  3. Plot e log[rate] versus log[conc] relationship and obtain the slope, yielding the rate law dependence.Use a spreadsheet to perform a linear regression analysis.
  4. Be able to discuss the possible sources of error and predict behavior when conditions are altered.