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Online Chemistry Labs | Learning Objectives

Background:

This laboratory introduces students to calorimetric determination of the heat of combustion of an organic compound. After performing a calibration run with a massed Al powder, the student calculates the calorimetric response of the equipment. The student next combusts a measured mass of an unknown and measures the heat rise. The student is assigned one of several different unknown compounds. From the observed J/g released, the student selects from a list of possible compounds and calculates the molar heat of combustion of the unknown. A realistic set of time-temperature data curves require extrapolation to obtain the true temperature change.

 Calorimetry

Learning Objectives:

  1. Become familiar with the principles of an oxygen combustion calorimeter.
  2. Introduce the concepts of calibration and extrapolation of time-temperature data to deal with heat losses and non-linear drift. 
  3. Perform the calculation of the equipment response factor.
  4. Illustrate how to determine the heat of combustion of an unknown.