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. © 2022 the author(s), published by De Gruyter, Berlin/Boston 2022
ABSTRACT
Social distancing measures due to the SARS-CoV-2 virus have profoundly challenged the educational experimental work. We have sought to remediate this issue by designing a series of low cost, low risk, quick, and qualitative electrochemistry and corrosion experiments to be performed in the student's homes at the microscale with a kit provided by the teacher. One such experience is the electroplating of Sn from an aqueous chloride solution using readily available soldering wires (e.g., Sn-Pb alloy, or Sn-Ag-Cu alloy). This process catches students' attention due to its simplicity and variety of possible applications that include corrosion protection, fabrication of electronic components, plating of cooking utensils, lithium batteries, etc. © 2022 Maite R. Herrera-Loya et al., published by De Gruyter, Berlin/Boston 2022.
ABSTRACT
This paper presents a student-designed one-pot electroless deposition of Bi extracted from a Pepto Bismol® tablet by galvanic displacement of the Zn coating of a galvanized iron nail. This experiment relies on a readily accessible and reasonably safe method and materials and it has been used during the present COVID pandemic as a hands-on activity with higher education students (i.e., Junior and Senior Chemical Engineering students). Its simplicity should allow its use with High School students as well. The entire procedure can be completed in 30-45 min. © 2021 Jose Luis Aguilar-Charfen et al., published by De Gruyter, Berlin/Boston.
ABSTRACT
Due to social distancing constraints during the COVID-19 pandemic, several experiments were designed in the Fall 2020 and Spring 2021 semesters in our Electrochemistry and Corrosion elective course to demonstrate electrochemical phenomena and applications at the students' homes with a kit sent by the school. We report here a student-designed experiment focused on water electrolysis, a well-studied phenomenon of great interest to the electrochemical industry. Its main appeal derives from the use of solar energy for the production of hydrogen gas, which is used in fuel cells. Here, the light-to-electricity converting function of light-emitting diodes is exploited to produce an electric current from solar radiation. This current is, in turn, utilized to perform microscale water electrolysis at graphite electrodes with the aid of a magnetic field. Lastly, the electrolysis products are employed to generate a voltage, demonstrating the fuel cell principle. ©