Affordances of Electrostatic Potential Maps in Promoting Use of Electronic Features and Causal Reasoning in Organic Chemistry

Instructional materials in organic chemistry include a wide variety of representations, such as chemical formulas, line-angle diagrams, ball-and-stick diagrams, and electrostatic potential maps (EPMs). Students tend to focus on explicit features of a representation while they are reasoning about chemical concepts. This study examined the affordances of electrostatic potential maps in students' approaches when the maps were integrated into four foundational organic chemistry problems using an experimental design approach. First-semester organic chemistry students were surveyed from two different institutions, where they made predictions and explained their reasoning behind identifying an electrophilic site, predicting the product, selecting the faster reaction, and classifying a mechanism. Students were randomly assigned to one of four surveys that differed by the representation they were given for the prompts: chemical formula, line-angle diagram, ball-and-stick diagram, and EPM. Responses from students with EPMs were analyzed and compared to responses from students with the non-EPM representations. Results indicated that students with EPMs had higher performance depending on the problem. They were also more likely to cite electronic features such as electron density, nucleophilicity, etc., and were more likely to use causal reasoning in their explanations. This study offers evidence in support of affordances of EPMs in promoting students' use of electronic features and causal reasoning. This evidence adds to the chemistry education literature by offering a potential means for promoting students' use of electronic features and causal reasoning by incorporating EPMs into assessment items. Implications for instruction include using EPMs in both instruction and assessment as a tool to help students build skills around invoking electrostatics and causal reasoning to solve problems in organic chemistry.