Organic chemistry students’ challenges with coherence formation between reactions and reaction coordinate diagrams

Abstract

The purpose of this study was to elucidate and describe students’ thinking when making connections between substitution and elimination reactions and their corresponding reaction coordinate diagrams. Thirty-six students enrolled in organic chemistry II participated in individual, semi-structured interviews. Three major themes were identified that characterize students’ difficulties with integrating the information from the reactions and the reaction coordinate diagrams: incorrect ideas about the meanings of the reaction coordinate diagrams’ features, errors when examining reaction mechanisms, and an inability to assess the relative energies of reaction species. These findings suggest that students need support for coherence formation between reactions and reaction coordinate diagrams. Implications for teaching to address these student difficulties are suggested.

Considering alternative reaction mechanisms: students’ use of multiple representations to reason about mechanisms for a writing-to-learn assignment

“…Studies in the literature also examine students' understandings of RCDs with investigations into how students interpret the meaning of RCD surface features (Lamichhane et al, 2018;Popova and Bretz, 2018a, 2018b, 2018cAtkinson et al, 2020. The studies by Popova and Bretz (2018a, 2018b, 2018c specifically report several findings about how organic chemistry students understand RCDs.…”

“…Studies in the literature also examine students' understandings of RCDs with investigations into how students interpret the meaning of RCD surface features (Lamichhane et al, 2018;Popova and Bretz, 2018a, 2018b, 2018cAtkinson et al, 2020. The studies by Popova and Bretz (2018a, 2018b, 2018c specifically report several findings about how organic chemistry students understand RCDs. For example, Popova and Bretz (2018a) identified that students in their study often viewed RCDs as encoding information that reflects only the major reacting species rather than all components of a reaction, often not considering the submicroscopic level.…”

“…For example, Popova and Bretz (2018a) identified that students in their study often viewed RCDs as encoding information that reflects only the major reacting species rather than all components of a reaction, often not considering the submicroscopic level. In another article, Popova and Bretz (2018b) identified that students demonstrated challenges when translating between mechanisms and RCDs for substitution and elimination reactions due to incomplete understandings of the information communicated by RCD surface features. They also found students have difficulty with this task because their reasoning with the mechanisms was often productoriented and focused on the surface features of reactants (Popova and Bretz, 2018b).…”

“…In another article, Popova and Bretz (2018b) identified that students demonstrated challenges when translating between mechanisms and RCDs for substitution and elimination reactions due to incomplete understandings of the information communicated by RCD surface features. They also found students have difficulty with this task because their reasoning with the mechanisms was often productoriented and focused on the surface features of reactants (Popova and Bretz, 2018b). The Popova and Bretz articles (2018a, 2018b, 2018c were all in the context of a course that primarily taught RCDs alongside reactions in first-semester organic chemistry (e.g., substitution, elimination, and addition reactions) but not in the second semester of instruction.…”

“…A growing body of research examines how students reason about organic reaction mechanisms with the EPF (Graulich, 2015). More recently, attention has focused on how students reason with RCDs (Lamichhane et al, 2018;Bretz, 2018a, 2018c), with one study examining how students match reactions to RCDs (Popova and Bretz, 2018b). However, few existing studies explore how introductory organic chemistry students reason with both of these representations together.…”