Secondary school students' understanding of the mole concept and its use in problem solving

النوع : Mémoire

This research attempts to study the conceptions held by students concerning the mole concept and its utilization in problem solving. It describes and compares grade 10 and grade 11 students’ ideas about: 1) the definition of the mole concept according to the international system (SI), 2) explaining the relationship between the mass ratio and the mole ratio of a substance, and 3) solving stoichiometric problems. To do so, a paper-pencil test was composed of three parts: the first part is related to the definition of the mole, the second part is related to the ability to solve problems that relate the amount of substance to masses in a chemical formula, and the third part is related to the ability to solve more complex stoichiometric problems using equations. The results of this study indicate that students develop insufficient understanding of the mole concept and use memorized algorithms to solve the problems. It also identifies the relationship between students’ reasoning abilities and their success in solving problems related to mass and moles. Due to their lack of understanding the mole concept, students use incorrect relations such as equating mole ratio with mass ratio or mole ratio with molar mass ratio. Furthermore, success in mole concept problem solving is directly related to a student’s mastery of mathematics concepts such as scientific notations and division problems.