Abrupt disruptions to academia, due to the COVID-19 pandemic in Spring 2020, have brought unprecedented challenges in teaching, yet it has brought many lessons, driving the development of strategies in response to the crisis. The general chemistry laboratory course is often considered difficult to teach, due to students' heterogeneous chemistry backgrounds and learning levels, and transitioning from in-person to remote teaching made it even more challenging. In this communication, we will share our experiences, strategies, and lessons learned from the remote teaching of a large general laboratory course at Brown University (Providence, RI, USA) during the pandemic. Future improvements to maximize student learning will also be outlined. Several novel approaches have been applied to our remote teaching; interactive lab videos, created prior to the pandemic through a collaborative effort for students to visualize the experimental procedures, enabled a less stressful transition to remote teaching for this large laboratory course. Furthermore, our hybrid lab reports, along with other online materials, helped students to better understand how experiments are conducted. The lessons learned from this pandemic prompted further improvement to the pedagogy of remote teaching. Such experiences and reflections will benefit other educators to combat pandemic crises in the future.

Introducing chemical equilibrium concepts in undergraduate general chemistry promotes improved understanding of chemical reactions. We have developed an engaging laboratory experiment exploring the equilibrium of cobalt complexation in alcohols using UV−vis spectroscopy and successfully implemented in a large general chemistry class of 378 students at Brown University. The octahedral to tetrahedral (pink to blue) cobalt complex transition generates vivid visualizations, increasing students' interest in learning. The equilibrium constants can be measured using UV−vis absorption spectroscopy and the Beer−Lambert law. Vast differences in molar absorptivity coefficients between octahedral and tetrahedral geometries of cobalt complexes prompt discussions on absorptivity, orbital splitting, and color change under the purview of learning Le Chatelier's principle. Additionally, the experimental results regarding the equilibrium constant allowed students to examine possible mechanistic pathways. Student responses to conducting the experiment were positive, most notably because this experiment encouraged them to analyze their experimental results critically and propose possible reaction mechanisms and equilibrium expressions while appreciating the sharp color transition that the complexation equilibrium undergoes.