An investigation of student understanding in the undergraduate organic chemistry laboratory

John Leo Grutsch, Purdue University

Abstract

Laboratory activities in organic chemistry involve a mixture of sophisticated logic and empirical observation that requires the integration of mechanistic thought, laboratory technique, and problem-solving skills. In an effort to understand how students develop the thought processes and problem-solving skills necessary for laboratory work in organic chemistry, student understanding of how the interaction between a reaction system (reactants or starting material(s), reagent(s), and/or solvent), experimental variables (pH, temperature, concentrations, etc), provides a result of interest (yield, selectivity, purity, etc.) for an experiment performed in the organic chemistry laboratory was investigated through the collection of responses to questions posed on pre-laboratory quizzes followed by in-depth interviews during which student volunteers discussed their responses along with their experiences in the laboratory. The conceptual change theory of learning which assumes new conceptions are understood, judged, acquired, or rejected in a conceptual context was used as a theoretical paradigm to examine students responses to questions posed on pre-laboratory quizzes and transcripts of the interviews with student volunteers. Students were found to not have developed a mechanistic understanding of how the interaction between a reaction system (reactants or starting material(s), reagent(s), and/or solvent), experimental variables (pH, temperature, concentrations, etc), provides a result of interest (yield, selectivity, purity, etc.) for an experiment performed in the organic chemistry laboratory. However, students' prior exposure to and understanding of chemical concepts was found to simultaneously assist and hinder in their development of a partial mechanistic understanding of how a reaction system (reactants or starting material(s), reagent(s), and/or solvent), experimental variables (pH, temperature, concentrations, etc), interact to provide a result of interest (yield, selectivity, purity, etc.). Even though students were able to develop a partial mechanistic understanding, they still did not understand the rationale behind chemical or physical manipulation performed in the organic chemistry laboratory or how either may be applied to other experiments. Therefore, experiments performed in the organic chemistry laboratory became activities in which students gave little thought to what they were doing resulting in little meaningful learning, unsafe practices, and an unpleasant experience that demotivated students. To address this deficiency, instructors need to create an environment where students are allowed to develop an understanding of the role of reagents and reaction conditions in an experiment in order to acquire the knowledge and skills that permits them to develop a deep mechanistic understanding of how organic chemistry reactions are implemented in the organic chemistry laboratory.

Degree

Ph.D.

Advisors

Bodner, Purdue University.

Subject Area

Organic chemistry|Science education|Higher education

COinS