Large, multi-section laboratory courses are particularly challenging when managing grading with as many as 35 teaching assistants (TAs). Traditional grading systems using point-based rubrics lead to significant variations in how individual TAs grade, which necessitates the use of curving across laboratory sections. Final grade uncertainty perpetuates student anxieties and disincentivizes a collaborative learning environment, so we adopted an alternative grading system, called specifications grading. In this system each student knows exactly what level of proficiency they must demonstrate to earn their desired course grade. Higher grades require demonstrating mastery of skills and content at defined higher levels. Each students' grade is solely dependent on the work they produce rather than the performance of other students. We piloted specifications grading in the smaller, third quarter course of the lower division organic chemistry laboratory series held during a summer term. Open-ended questions were chosen to gather student and TA perceptions of the new grading system. TAs felt that the new grading system reduced the weekly grading time because it was less ambiguous. Responses from students about the nature of the grading system were mixed. Their perceptions indicate that initial buy-in and multiple reminders about the bigger picture of the grading system will be essential to the success of this grading system on a larger scale. File list (2) download file view on ChemRxiv CHEMRXIV_REVISED2-Developing and Implementing a ... (1.17 MiB) download file view on ChemRxiv Supporting Information.pdf (441.79 KiB)

The instruction of high enrollment general and organic chemistry laboratories at a large public 10 university always have curricular, administrative, and logistical challenges. Herein, we describe how we met these challenges in the transition to remote teaching during the COVID-19 pandemic. We discuss the reasoning behind our approach, the utilization of our existing web-based course content, the additions and alterations to our curriculum, replacement of experimental work with videos, the results of both student and TA surveys, and lessons learned for iterations of these courses in the near 15 future. File list (3) download file view on ChemRxiv CHEMRXIV_REVISED-Online in No Time.pdf (1.34 MiB) download file view on ChemRxiv Online in No Time Supporting Information.pdf (181.10 KiB) download file view on ChemRxiv bigbrother_python_code.py (3.15 KiB)

A new undergraduate organic chemistry laboratory experiment has been developed to determine the absolute configuration of enantioenriched secondary alcohols with the competing enantioselective conversion (CEC) method. The CEC method uses both enantiomers of a chiral kinetic resolution reagent in parallel reactions to identify the fast-reacting reagent and thus the configuration of the alcohol. Students working in pairs are given one of three enantioenriched secondary alcohols with an unknown absolute configuration. They assign the molecular structure using the corresponding 1H NMR spectrum and determine the absolute configuration via the CEC method. The parallel reactions are run at room temperature for 1 h using small quantities of solvent, substrate, and catalyst. Students use thin-layer chromatography (TLC) to analyze the parallel reactions and determine the fast reaction qualitatively. The free program ImageJ is used with a picture of the TLC plate to carry out a quantitative analysis of reaction conversion. Data collected in the spring 2013 laboratory course (n = 1036) show that 93.6% of students determined the absolute configuration of their unknown correctly with just a qualitative analysis of the TLC plate. This experiment provides a platform for discussions of stereochemistry, mechanism, kinetics, energy diagrams, and transition states.

The instruction of high enrollment general and organic chemistry laboratories at a large public 10 university always have curricular, administrative, and logistical challenges. Herein, we describe how we met these challenges in the transition to remote teaching during the COVID-19 pandemic. We discuss the reasoning behind our approach, the utilization of our existing web-based course content, the additions and alterations to our curriculum, replacement of experimental work with videos, the results of both student and TA surveys, and lessons learned for iterations of these courses in the near 15 future.

Assumptions about the feasibility of teaching chemistry laboratories online have been challenged by the ongoing COVID-19 pandemic. We argue that, despite the fact that pandemic social distancing restrictions will be eventually eliminated, the development of quality digital laboratory resources must continue to receive attention from the chemistry community. Even if higher education institutions fully return to in-person operating conditions, these materials could serve as prelaboratory preparation to reduce student anxiety, as supplementary support materials to enhance student understanding, as optional distance education resources for students unable to be present in the laboratory, and as training materials for teaching assistants.