摘要:The purpose of this study was to describe and classify the strategies high school students use when solving stoichiometry problems and compare and contrast problem solving strategies of students with different learning approaches and different conceptual understanding levels. Subjects were forty students enrolled in two sections of a Grade 11 class in a highly selective private school in Lebanon. Three sources of data were utilized in this study: The Learning Approach Questionnaire (LAQ), the Stoichiometry Test, and unstructured interviews. 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 algorithmic, efficient, and messy while the incorrect strategies were subdivided into Incorrect strategies-Incorrect answer and Incorrect strategies-Correct answer. Results showed that learning approach was not related to conceptual understanding or to specific types of problem solving strategies and that the overwhelming number of strategies used were algorithmic with very few efficient ones. Moreover, conceptual understanding was found to be a determining factor in students' success in solving the problems.