Assessing college students' understanding of acid base chemistry concepts

Typically most college curricula include three acid base models: Arrhenius', Bronsted-Lowry's, and Lewis'. Although Lewis' acid base model is generally thought to be the most sophisticated among these three models, and can be further applied in reaction mechanisms, most general chemistry curricula either do not include Lewis' acid base model, or quickly mention it at the end of the acid base chapter, because of the concern that Lewis' model may confuse general chemistry students (Shaffer 2006). While such a disconnection in curriculum might put students to disadvantage as they try to construct solid and coherent acid base mental models, there has not been any research data to favor one curriculum over another. The large sizes of general chemistry courses at most universities (from one hundred to several hundred students per lecture section) pose further challenges to the comparison of different general chemistry curricula on their effectiveness in helping students construct acid base mental models. In light of these challenges, the research questions I focused on were: 1) What are the important characteristics of activities that effectively promote and retain argumentation skills among college students? 2) In what ways is argumentation an effective assessment method for student understanding of acid base models? 3) How do different curricula affect students' acid base models? This dissertation presents promising results from using BeSocratic activities in promoting argumentation skills among college students and at the same time using their responses in the activities to understand aspects of their acid base mental models, and compare how two different general chemistry curricula affected students' acid base mental models.