Working with mental models to learn and visualize a new reaction mechanism

Creating and using models are essential skills in chemistry. Novices and experts alike rely on conceptual models to build their own personal mental models for predicting and explaining molecular processes. There is evidence that chemistry students lack rich mental models of the molecular level; their mental models of reaction mechanisms have often been described as static and not process-oriented. Our goal in this study was to characterize the various mental models students may have when learning a new reaction mechanism and to explore how they use them in different situations. We explored the characteristics of first year organic chemistry students’ (N = 7) mental models of epoxide-opening reaction mechanisms by qualitative analysis of transcripts and written answers following an audio-recorded interview discussion. We discovered that individual learners relied on a combination of both static (with a focus on symbolism and patterns) and dynamic (reactivity as process or as particles in motion) working mental models, and that different working mental models were used depending on the task. Static working mental models were typically used to reason generally about the reaction mechanism and products that the participants provided. Dynamic working mental models were commonly used when participants were prompted to describe how they pictured the reaction happening, and in attempting to describe the structure of a transition state. Implications for research, teaching, and learning from these findings are described herein.