What Are They Seeing? How Students Predict and Explain Substitution and Elimination Reactions

• Main Author: Hunter, Kevin H
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2023
• Subjects: Chemistry; Education; Science education
• ISBN: 9798379793999

Reasoning about reaction mechanisms has been a noted difficulty for students in organic chemistry. Substitution and elimination reactions often represent the first time that students are required to think about the deeper reasoning behind these processes, but not much research has been done about how students broadly conceptualize these reactions. Here, we focus on developing a description of the ways that students conceptualize bimolecular and unimolecular substitution and elimination reactions. Through the lens of coordination class theory as a theoretical framework, our analysis identifies the visual features students attend to and knowledge they coordinate when reasoning about reaction mechanisms across multiple tasks. Based on the data gathered from ten semi-structured student interviews, we developed representations of the ways students conceptualize the four reaction mechanisms and how they explained and predicted those reaction mechanisms on exam-type tasks. Our data indicates that across tasks, students place a heavier emphasis on the importance of the starting substrate in the outcome of a reaction but less focus on the function of the nucleophile or base in each reaction. Students need support in reasoning about all species in a reaction mechanism and coordinating those features when making predictions about a reaction’s outcome. Based on this, we provide implications for researchers and practitioners.