Analysing the Impact of a Discussion-Oriented Curriculum on First-Year General Chemistry Students' Conceptions of Relative Acidity

Instructional strategies that support meaningful student learning of complex chemical topics are an important aspect of improving chemistry education. Adequately assessing the success of these approaches can be supported with the use of aligned instruments with established psychometrics. Here, we report the implementation and assessment of one such curriculum, "Chemical Thinking," on first-year general chemistry students' conceptions of relative acidity using the recently-developed concept inventory, "ACIDI." Our results reveal that, overall, students performed significantly better on "ACIDI" following instruction, with scores consistent with those previously reported for students who had completed one semester of organic chemistry. Students performed equally well on a delayed post-test administered ten weeks after final instruction, which suggests that instruction promoted a stable conceptual reprioritisation. Item analysis of "ACIDI" revealed that students generally made conceptual gains on items where inductive effects were the primary determinants of conjugate base stability and relative acidity. However, students overwhelmingly struggled on items where resonance was the primary determinant. Analysis of student-student arguments in active learning settings provided evidence for how the quality of student arguments impacted their conceptions. Overall, these findings suggest that students were able to avoid several superficial misconceptions cited in the literature about relative acidity, and that this topic, traditionally taught exclusively in organic chemistry, may be introduced earlier in the sequence of curricular topics. Implications for future studies on the role of argumentational aspects of student-student conversations and facilitation strategies in promoting or hindering meaningful learning are discussed.