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Online Chemistry Labs | Learning Objectives

Background:

This experiment requires the student to obtain thermodynamic data for a reaction using a voltaic cell. The cell reaction involves a Cu electrode in a Cu2+ aqueous solution versus a Pb electrode in a Pb2+ solution. The temperature of the cell is controlled over a temperature range of 15°C to 33°C. Voltage readings are taken at regular intervals. The noise in the readings is comparable to the change in the readings over the temperature range. The student must use linear regression to fit a straight line to the voltage versus temperature plot to obtain values for ΔG°, ΔH°, and ΔS° to compare with literature values. An analysis of the experimental errors in the values is performed, and the assumptions made are evaluated.

 Entropy

Learning Objectives:

  1. Study a typical method for obtaining thermodynamic data for a reaction.
  2. Be able to derive useful data from an experiment that poses significant errors which must be overcome.
  3. Be able to evaluate the importance of experimental error when comparing results with literature values.
  4. Be able to calculate the theoretical temperature at which a reaction is at chemical equilibrium.
  5. Be able to evaluate the assumptions inherent in this method.