This presentation deals with the sequence of three experiments performed in experimental physical chemistry course, CHEM 457, at the department of chemistry at Penn State. The sequence was design in order to build/enhance the students’ capacity for complex problem solving and consists of the following experiments: (1) Pyrene fluorescence quenching by iodide, (2) Pyrene excimer formation, and (3) Photophysical study of the thermodynamics of analyte-stationary phase interaction.  The learning goal of the first experiment is to fortify the previously learned basics of chemical kinetics (reaction order, first, pseudo-first and second order reactions, and the corresponding rate constant measurements) by measuring the second order rate constant of a photo-induced reaction. In addition to exercising the basic lab skills, the students learn how to operate a nanosecond laser photolysis setup and to process the data obtained. The second experiment  lab objective is to learn how combined steady state fluorimetry and time resolved laser photolysis measurements are used to elucidate a complex photochemical reaction system comprising two parallel and two consecutive reactions. The corresponding data processing and error analysis are more complex than that in the first experiment and are appropriate for learning at this cognitive level. During the third experiment, the students learn Procedural Knowledge, that is, how to do something, methods of inquiry, and criteria for using skills, algorithms, techniques, and methods. In particular, analyte concentration distributions are determined for the loading peak and eluted peaks at several migration distances in a 30 cm long column packed with silica gel. Discrete band profiles are fit using either exponentially modified Gaussian or Gaussian functions for elution and static diffusion, respectively. Using the fitted concentration profiles, figures of merit such as retention factors, equilibrium constants, changes in Gibbs free energy, and peak asymmetry are determined. In addition, the pyrene concentration profile in a static mobile phase is monitored as a function of time at a migration distance of ca. 73 mm, from which the axial diffusion coefficient of the analyte in equilibrium between the stationary and mobile phase is determined. During this presentation, it will be explained how the third experiment can be modified to design new related experiments that produce new knowledge.

Utilizing the pyrene photophysics and photochemistry in three linked experiments for preparing students for complex problem solving

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.