Investigating Pre-service Chemistry Teachers’ Problem Solving Strategies: Towards Developing a Framework in Teaching Stoichiometry

Abstract

The present study investigated pre-service chemistry teachers' problem solving strategies and alternative conceptions in solving stoichiometric problems and later on formulate a teaching framework based from the result of the study. The pre-service chemistry teachers were given four stoichiometric problems with increasing complexity and they need to write the process that they undertake to solve the problem. The study found out that the most prominent strategy among pre-service chemistry teachers is the mole method, which is algorithmic by nature. Very few of them used the proportionality method and none made use of the logical method. Alternative conception noted among the pre-service chemistry teachers is that some of them rely on Avogadro's number in converting between moles with a given mass. The results indicate that these pre-service chemistry teachers has the tendency to teach stoichiometry using the mole method only and that they might carry on the alternative conception about Avogadro's number as they start their teaching career. It is therefore suggested that the teaching of stoichiometry to pre-service chemistry teachers should not be confined to demonstration as they will imitate such technique when they are already a full pledged chemistry teacher. They should be involved in the process of thinking of ways to solve the stoichiometric problem in such a way that it will help them become independent thinkers and be responsible for their own learning by developing metacognitive and critical thinking strategies.

Understanding How Chemistry Teachers Transform Stoichiometry Concepts at Secondary Level in Lesotho

“…9 Anecdotal evidence suggests that many teachers in Lesotho struggle with the teaching of stoichiometry and that many students do not perform well in stoichiometry questions in external examinations. Research elsewhere shows that stoichiometry demands special efforts from teachers to develop effective teaching strategies 10 , drawing on their topic specific Pedagogical Content Knowledge (PCK). 11,12 This study explored the construct of PCK within the context of science education in Lesotho.…”

Assessment: A Suggested Strategy for Learning Chemical Equilibrium

“…Stoichiometry is considered as a complex concept and it is associated with misconceptions of chemistry language, no specific organization of thoughts in solving problems, the incorrect application of reasoning, and an unsupportive environment [85].…”

Analyzing Characteristics of Experts in the Context of Stoichiometric Problem-Solving

“…Student difficulties with problem-solving are persisting with students having difficulty with problem-solving due to the use of ineffective strategies and lack of confidence in their problem-solving abilities [14,20]. As a deeper probe into problem-solving, comparisons between expert and novice problem-solving pathways [21,22] have been widely studied and reported across a range of subjects including physics [23] and chemistry [24,25]. The literature on experts' problem-solving strategies, their overall success in problem-solving, and their differences from novices are quite prevalent throughout the academic community.…”

“…Specifically, what subproblems are chunked by experts and how does this vary based upon experience. A previous study [25] investigated how an expert solves algorithmic and conceptual problems but only focused on the time spent in 1 of 5 stages, providing little information about the details of problem-solving and how subproblems are effectively chunked by experts. This study aims to analyze how experts, with variable backgrounds and careers, approach solving stoichiometry exercises.…”