Secondary school students' difficulties with stoichiometry

This article aims to identify the misunderstandings and problem-solving strategies of secondary school students when solving stoichiometry problems. The two sources of data were the Stoichiometry Test and unstructured interviews. Results showed that students have misunderstandings in five topics related to stoichiometry (molar quantities, limiting reagent, conservation of matter, molar volume of gases at STP, coefficients in a chemical equation). The problem-solving strategies used by the students were classified into three categories: correct strategies, incorrect strategies, and incomplete strategies. The correct strategies were further subdivided into traditional, efficient, and messy while the incorrect strategies were subdivided into incorrect strategies-incorrect answer and incorrect strategies-correct answer.