ERIC Number: EJ759017
Record Type: Journal
Publication Date: 2005-Mar
A Guided Inquiry Experiment for the Measurement of Activation Energies in the Biophysical Chemistry Laboratory: Decarboxylation of Pyrrole-2-Carboxylate
Hutchinson, Kelly M.; Bretz, Stacey Lowery; Mettee, Howard D.; Smiley, Jeffrey A.
Biochemistry and Molecular Biology Education, v33 n2 p123-127 Mar 2005
A laboratory experiment for undergraduate biophysical chemistry is described, in which the acid concentration and temperature dependences of the decarboxylation of pyrrole-2-carboxylate are measured using a continuous ultraviolet (UV) spectrophotometric assay. Data collection and analysis are structured using principles of guided inquiry. Data leading to the calculation of multiple rate constants at varying temperatures and acid concentrations can be collected within one laboratory period, using inexpensive reagents and standard instrumentation. These experiments permit determination of activation energies that are lower at high acid concentration, indicative of a subtle change in the reaction mechanism with decreasing pH. The reaction is readily observable by students as they collect UV spectrophotometry data, and the decarboxylation reaction is related to biologically relevant enzymatic reactions.
Descriptors: Laboratory Experiments, Chemistry, College Science, Undergraduate Students, Biochemistry, Science Experiments, Spectroscopy, Inquiry, Energy, Science Instruction
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Publication Type: Guides - Classroom - Teacher; Journal Articles; Reports - Descriptive
Education Level: Higher Education
Authoring Institution: N/A