Students’ mental models of chemical reactions and balancing of chemical equations : A case study of a Ghanaian senior high school

Abstract

This study investigated students’ mental models of chemical reactions and balancing chemical equations at Diamono Senior High School in the Brong Ahafo region of Ghana. The study employed case study design using Action Research approach. An intact class of form 2 science class made up of 24 males and 6 female students’ were used for the study. The data for this study were derived from class exercises done by students to probe their mental models of chemical reactions and balancing chemical equations for various chemical phenomena. Data collected from the study was analysed qualitatively. Thematic analysis of the students’ discourse of their mental models revealed different types of mental models; named Model A, B, and C. Model A was considered as an initial mental model, which was based on students’ experience with changes of matter in their daily life. Model B was based either on the attributes related to the kinetic theory of particles or attributes related to chemical bonding. Model C was based on students’ scientific ideas but include some erroneous assumptions. A general conclusion drawn from this study was that, some students’ mental models were found to be lacking in attributes that relate to scientific ideas such as particle model, particle collisions, activation energy and entropy, despite being introduced with these ideas in their formal learning. It is suggested that students’ should be introduced to model-based instruction that encourages them to construct acceptable mental models of particles and link these models with the chemical phenomena. Therefore, an inquiry that investigates the impact of an intervention would be beneficial.