Students’ interpretations of mechanistic language in organic chemistry before learning reactions

Abstract

Research on mechanistic thinking in organic chemistry has shown that students attribute little meaning to the electron-pushing (i.e., curved arrow) formalism. At the University of Ottawa, a new curriculum has been developed in which students are taught the electron-pushing formalism prior to instruction on specific reactions—this formalism is part of organic chemistry's language. Students then learn reactions according to the pattern of their governing mechanism and in order of increasing complexity. If students are fluent in organic chemistry's language, they should have lower cognitive load demands when learning new reactions, and be better positioned to connect the three levels of chemistry's triplet (i.e., Johnstone's triangle). We developed a qualitative research protocol to explore how students use and interpret the mechanistic language. Twenty-nine first-semester organic chemistry students were interviewed, in which they were asked to (1) explain a mechanism, given all the starting materials, intermediates, products, and electron-pushing arrows, (2) draw in arrows for a reaction mechanism, given the starting materials and products of each step, and (3) predict the product of a reaction step, given the starting materials and electron-pushing arrows for that step. To investigate the students’ ideas about mechanistic language rather than their knowledge of specific reactions, we selected reactions for the interview guide that had not yet been taught. Following transcription, we analyzed the interviews using constant comparative analysis to explore how students used and interpreted the mechanistic language. Four categories of student thinking emerged with electron movement underlying students’ thinking throughout the interviews. Herein, we discuss these categories, students’ interpretation of the symbolism, connections to learning theory, and implications for teaching, learning, and research.

Development and evaluation of a Lewis acid–base tutorial for use in postsecondary organic chemistry courses

“…Such work should be built using the vast array of literature that exists regarding student understanding of organic chemistry reaction mechanisms. 26,27,[64][65][66][67][68][69][70] For example, research findings related to student understanding of other reaction types and components of reactions (e.g., nucleophiles and electrophiles, 71,72 leaving groups 73 ) could be used to develop additional tutorials.…”

An online categorization task to investigate changes in students' interpretations of organic chemistry reactions

“…The course has been described as a difficult and confusing course for undergraduate students (Anderson & Bodner, ; Bradley, Ulrich, Jones, & Jones, ) and often has high attrition rates (Grove, Hershberger, & Bretz, ; Rowe, ). Novices in the domain of organic chemistry may initially struggle with fundamentals of chemistry and yet can become proficient, including in areas of interpreting functionality of chemical structures (Bodé, Caron, & Flynn, ; Flynn et al, ), placing meaning to the symbolic language of organic chemistry (i.e., the electron‐pushing formalism) (Flynn & Featherstone, ; Galloway, Stoyanovich, & Flynn, ), and organizing their knowledge around the deep underlying concepts of organic reactions (Galloway, Leung, et al, , ). Moreover, students' understanding can be based on surface‐level features rather than process or reactivity‐oriented concepts (Cruz & Towns, ).…”

“…Ideally, students become better able to explain the chemical basis for reaction mechanisms (i.e., causal mechanistic reasoning), analyze competing reaction pathways, predict the reactivity of unknown reactions, and transfer these principles of reactivity to other areas and disciplines (Flynn & Ogilvie, ). A curriculum evaluation is underway using a design‐based research approach (Cobb, Confrey, diSessa, Lehrer, & Schauble, ), in which studies have been performed to assess students' knowledge and skills in the context of the transformed curriculum (Galloway, Leung, et al, , ; Galloway, Stoyanovich, et al, ; Webber & Flynn, ). The present study extends this evaluation, investigating how students chose and were able to organize their knowledge around organic chemistry reactions and how this organization changed over time as a reflection of aspects of their expertise in organic chemistry.…”

What are students’ learning and experiences in an online learning tool designed for cognitive and metacognitive skill development?

“…Students struggle, however, with organic chemistry's symbolism (Kozma & Russell, 1997) and in order for students to learn organic chemistry concepts, they must learn how to speak and understand the language (Taber, 2009). Students may struggle to become H DOI: 10.22329/celt.v11i0.5039 fluent in organic chemistry's language because of its technical and specialized vocabulary in addition to the symbolism (Bhattacharyya, 2013;Galloway, Stoyanovich, & Flynn, 2017). In this article, we describe an open education resource that empowers students to master this language, the Organic Mechanisms module in orgchem101.com.…”