INVESTIGATING GRADUATE TEACHING ASSISTANTS’ MISCONCEPTIONS IN CHEMICAL EQUILIBRIUM: IMPLICATIONS FOR PEDAGOGICAL SUPPORT

Abstract

This study examines the misconceptions about chemical equilibrium held by first-year graduate teaching assistants (GTAs) in a general chemistry course (CHEM 1). To address the research questions, a Chemical Equilibrium Diagnostic Test (CEDT) and a targeted mini-lecture were developed and implemented. Data were collected from two separate cohorts in Spring 2023 (N=10) and Fall 2023 (N=11) through pre- and post-assessments using the CEDT, classroom observations, and follow-up interviews.Pre-assessment scores averaged 7.10/14 in Spring 2023 and 5.82/14 in Fall 2023, revealing widespread misconceptions, such as misapplying thermodynamic reasoning to predict changes in reaction rate, confusing mass with concentration, and incorrectly applying Le Châtelier’s Principle. Among these, 60% of Spring 2023 GTAs incorrectly believed that lowering the temperature shifts an exothermic equilibrium backward, and 36% of Fall 2023 GTAs believed that removing a reactant would cause a passive decrease in another reactant. Misconceptions were also observed in GTAs’ instructional practices during laboratory sessions. For example, one GTA defined equilibrium as the point at which the concentrations of reactants and products are equal, while another incorrectly stated that decreasing pressure shifts equilibrium toward the side with fewer gas molecules. These findings suggest that, without structured guidance, GTAs may unintentionally introduce or reinforce student misconceptions during lab instruction. Post-assessment scores improved in both cohorts, particularly among mini-lecture attendees. In Spring, attendees improved by 2.5 points while non-attendees by 1.5; in Fall, attendees improved by 2.0 points and non-attendees by 0.66. Although mixed ANOVA results did not show a statistically significant interaction between mini-lecture attendance and score gains, item-level analyses revealed that attendees more frequently corrected specific misconceptions and adopted more precise, IUPAC-aligned terminology. Interview data (N=4) indicated that GTAs found both the diagnostic test and the mini-lecture helpful. Participants recommended regular content reviews, stronger alignment between lab and lecture materials, and standardized instructional resources to reduce preparation time. The findings contribute to the broader field of TA training by demonstrating that brief and targeted pedagogical interventions can meaningfully improve GTAs’ conceptual understanding and instructional delivery of foundational chemistry topics.