Total Chemical Footprint of an Experiment: A Systems Thinking Approach to Teaching Rovibrational Spectroscopy

Abstract

Rovibrational spectroscopy is a fundamental component of most physical chemistry curricula. This article describes an adaption of the rovibrational spectroscopy of carbon dioxide experiment that can be used as a stand-alone experiment or in conjunction with a traditional hydrogen chloride experiment. The case is made that the laboratory investigation of carbon dioxide provides students with an alternative learning experience to hydrogen chloride experiments alone because the spectroscopic properties of carbon dioxide facilitate a wider discussion and integration of important physical chemistry concepts either directly or peripherally related to rovibrational spectroscopy. However, the motivation to use carbon dioxide is driven by green chemistry considerations. By applying a systems thinking approach to the green chemistry principle of reducing or eliminating toxic reagents, the proposed experiments use only ambient atmospheric carbon dioxide to completely eliminate any purchased reagent. Additionally, without the need for vacuum lines, pumps, traps, and IR gas cells to prepare a sample, instructors can discuss with students the concept of the total chemical footprint of an experiment in relation to not only the reagents but the equipment used to perform the experiment. The use of carbon dioxide also facilitates a discussion of issues related to climate change that reinforces the systems thinking methodology to green chemistry.