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Online Chemistry Labs | Learning Objectives

Background:

This laboratory introduces students to the classic combustion analysis experiment in which an organic compound containing only C, H, and O is combusted in excess oxygen to produce CO2 and H2O, which are captured in traps that are weighed on the balance before and after the run. After performing a run with a known compound, the student performs the same type of analysis on an unknown. The student is guided through the calculation of moles of C and H in each compound, followed by calculation of the moles of O, leading in each case to the determination of the two empirical formulae. The student is assigned one of several different unknown compounds.

 Combustion

Learning Objectives:

  1. Become familiar with the principles of a combustion apparatus for burning an organic compound in oxygen by manipulating the valves properly and weighing the traps and reagents.
  2. Introduce the concept of carbon-hydrogen analysis via combustion to carbon dioxide and water. 
  3. Perform the calculation of the moles of C, H, and O in the combusted compounds.
  4. Illustrate how to determine empirical formula from the mole ratios of C:H:O.
  5. Be able to discuss sources of error and suggest test experiments to confirm proper operation.