No abstract

As a result of social distancing measures in response to the Covid-Sars 2 pandemic, our school sent chemistry kits to the students’ homes for remote experimentation. This allowed the performance of ∼25 experiments per person in each of the Fall 2020 and Spring 2021 semesters in an elective chemistry course. Students were requested to design some experiments of their own and then have the entire group reproduce them. One such experiment consisted of the anodic indirect electrogeneration of colloidal sulfur by solution acidification to produce thiosulfate disproportionation. This was evidenced by the well-known Rayleigh scattering phenomenon. Here, the trajectory and polarization state of light are modified by its interaction with a medium containing particles of smaller diameter than the wavelengths of incident light. If white light interacts with this medium, the smaller wavelengths (e.g., blue, violet) are radially scattered while the longer wavelengths (e.g., orange, red) pass through the suspension. Such scattering is responsible for beautiful sunsets and blue skies and is produced here by an indirect electrochemical process that generates colloidal sulfur. Students evidence the scattering of light shone from simple cell phone flashlights. The entire procedure is performed in a 2-h class session. Key student outcomes are presented.

During the SARS-2-Covid pandemic our institution sought to continue the teaching and learning of experimental laboratories by designing, assembling, and delivering a microscale chemistry kit to the students´ homes. Thanks to this approach students were able to perform ~25 experiments during each one of the Fall 2020 and Spring 2021 semesters in an elective Electrochemistry and Corrosion course offered to Chemical Engineering undergraduates. In addition to performing traditional experiments, students were encouraged to design some of their own and have the entire group reproduce them. One of such student-designed experiments involved the capture of CO2 and its reduction with a readily available active metal (i.e., Al foil) in aqueous media to generate potentially useful products. The highly negative standard potential of Al is exploited for the reduction of lab-generated CO2, and the products are chemically tested. Al as a foil has been reported to be electrochemically inactive for carbon dioxide reduction. However, encouraged by an earlier report of the reduction of CO2 to CO, the Al surface is activated in the present experiment by removal of its natural oxide layer with a solution of CuCl2 produced in an electrochemical cell. This procedure enables Al to react with CO2 and yield useful chemistry. This experiment turned to be a discovery trip. The detailed procedure is discussed here, as well as the teaching methodology, grading scheme, and student outcomes.

In view of the COVID-19 pandemic and the ensuing lock-down, we assembled an experimental kit composed of basic lab items and sent it to each student´s home before the start of the Fall 2020 and Spring 2021 semesters so that the experimental activities would not be discontinued. The kit contained electrical components, general laboratory items and glassware, electrode materials, volume measurement and transfer equipment, various solutions and reagents, and safety equipment. Students performed 25 remotely supervised experimental activities each semester in the following areas: basic electrical circuits and measurements, redox reactions, energy generation and storage, electroless and electrodeposition, environmental electrochemistry, water electrolysis, organic electrochemistry, inorganic electrochemistry, and corrosion. Such hands-on experiences were very successful. Student learning outcomes were assessed.