R. Thomas Smith, Justin Carmel, Ellen Yezierski (Miami University, USA)
Stoichiometry is a fundamental chemistry concept, which students begin learning in high school and is further developed throughout college level chemistry courses. Typically, it is approached through problems and exercises focused on the mathematical and symbolic domains. Even in light of a body of research which suggests otherwise, some topics are treated solely through problem solving without aiming to explicitly develop students’ conceptual understanding. Conceptual understanding for this study is framed by Alex Johnstone’s work and is augmented by a mathematical domain (Donald Wink). This means that students can accurately describe matter and its changes in four domains (particulate, symbolic, macroscopic, and mathematical) and make connections between them. A diagnostic assessment comprised of twelve test items was developed. Each item asks a question in one domain and requires an answer in a different domain (e.g. symbolic question requiring a particulate answer). Semi-structured interviews with 20 first semester general chemistry students working through the assessment will reveal which domain connections are most challenging for students post-instruction. Results will be presented.