Graduation Year

2026

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Chemistry

Major Professor

Scott E. Lewis, Ph.D.

Committee Member

Jeffrey Raker, Ph.D.

Committee Member

Sandra Schneider, Ph.D.

Committee Member

Ioannis Gelis, Ph.D.

Keywords

intermolecular forces, molecular representation, reaction mechanisms

Abstract

Chemical representations play a central role in how students learn and reason aboutchemistry. While representations are routinely used in chemistry classrooms, students often struggle to extract relevant information, connect representations to underlying chemical principles, and apply this information to problem-solving. This dissertation investigates the role of representations in supporting students’ conceptual understanding and reasoning across general and organic chemistry through three qualitative studies.

The first study in this work explores how variation in chemical representation influences how students understand foundational chemistry principles. This study sought to characterize how second semester general chemistry students approach dipole–dipole interaction tasks with four distinct representations. Eighteen participants were recruited for semi-structured interviews, and their strategies to solve the tasks were analyzed to examine the influence of both representation features and their presentation order. Findings revealed that students’ approaches were shaped by the explicit features within each representation, and the sequence in which representations were presented influenced which features students noticed and applied. These findings highlight the importance of carefully selecting representations that emphasize features aligned with the target concept, ensuring students attend to elements that support their foundational understanding. Additionally, when introducing a new representation, it is essential to explicitly guide students in exploring both its implicit and explicit features so they can recognize and interpret the properties being conveyed.

The second study in this work builds on the idea that representations are influential factors in students understanding of chemistry and explores the utility of electrostatic potential maps (EPMs) in promoting mechanistic reasoning in organic chemistry. Nineteen students participated in semi-structured interviews that examined their use of EPMs with concealed and then revealed atomic identities to predict reaction outcomes. When atomic identities were hidden, participants focused on electron density patterns to guide their reasoning. Upon revealing the identities, most students reverted to memorized reaction mechanisms, though a subset attempted to integrate electron density with atomic identity. These findings highlight the potential of EPMs as an intervention to encourage sense-making and support deeper reasoning in organic chemistry.

The third study further investigates the use of EPMs to support conceptual change in students’ understanding of intermolecular forces. Thirteen general chemistry students completed a set of tasks on intermolecular forces, first using Lewis-dot structures and then the same tasks presented with EPMs. Students were also given the opportunity to compare their responses across the two representations. Analysis revealed that EPMs often promoted productive conceptual changes by challenging prior conceptions but occasionally introduced additional complexities that caused students to question their canonical understandings. This study emphasizes both the promise and the challenges of integrating EPMs into instruction and suggests that integration of EPMs may enhance students’ proficiency with foundational chemical concepts when learning chemistry. Collectively, these studies advance our understanding of how chemical representations shape student thinking and provide practical insights for leveraging representations to support learning in the chemistry classroom.

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