Exploring the progression in students' understanding of chemical reactions across different grade levels

Abstract

This study aimed to map students’ conceptual progression of how and why chem ical reactions happen across different grade levels. This study also investigated how students’ patterns of understanding change with respect to the type of chemical re action under analysis. A total of 77 students participated in the study from different grade levels: Grade 12 students in high school level (n=20), Undergraduate 1 chem istry students (n=20), Undergraduate 4 chemistry students (n=20), and Graduate chemistry students (n=17). Grounded theory was utilized as the research method ology and semistructured individual interviews were conducted with the participants. Semistructured interview protocol included four types of chemical reactions (i.e., single displacement, double displacement, decomposition, and combination) based on parti cle arrangements. Through constant comparative analysis of the data, dimensions and conceptual modes were identified and conceptual modes were sequenced based on in creasing sophistication. Data analysis showed that students’ understanding of how and why chemical reactions happen depended on the grade level and the reaction type un der analysis. The findings showed that the participants’ understanding demonstrated progression regarding how chemical reactions proceed and chemical causality as the grade level increased. The participants mostly struggled while explaining the agents, processes, energetic, and entropic factors affecting chemical reactions. Therefore, the expression of the conceptual modes regarding the dimensions of what causes chemi cal reactions and what drives chemical reactions was lower when compared with the other dimensions. The findings of the study seemed to provide insights into designing curriculum, developing assessment tools and instructional practices.