Adapting Meaningful Learning Strategies to Teach Liquid–Liquid Extractions

Although teaching laboratories offer students the opportunity to act and think like chemists, in many cases students simply follow written procedures to generate predetermined outcomes. In recent years, there has been a movement toward inquiry-, problem-, and discovery-based learning. In a similar vein, the first-semester introductory organic chemistry laboratory curriculum at the University of Michigan was recently overhauled, informed by the strategies of meaningful learning. The new course consists of three interconnected modules, and we present herein the second module, which focuses on liquid-liquid extraction (LLE). In the first week, students learn how to perform LLE by designing their own separation of a dye mixture, gaining an understanding of how the solution pH impacts molecular structure and solubility. In the second week, they practice using LLE by designing a separation method to remove a pollutant from water, and then, in the third week, they apply LLE to isolate a reaction product. We assessed student learning through a writing assignment at the end of the three-week module. We also assessed how the overall course affects student understanding of LLE concepts and their confidence in the lab. Our findings suggest that this learn, practice, apply approach for teaching LLE leads to modest learning gains and increased confidence.