First year prospective teachers' perceptions of molecular polarity and properties of solutions

The purpose of this study is to explore the perceptions of first year students regarding particular concepts of solution chemistry and to determine the difficulties that students may have in understanding these concepts. The test was administered to 122 first year undergraduates enrolled in the Elementary Science Teacher Education Department of a State University, Turkey, at the end of spring semester during 2007 educational year. A diagnostic survey composed of 4 open-ended items was prepared for this study. Items-1 and 2 required students to define the polar/non-polar molecule and the solubility. Item-3 examines the students' reasons to explain why freezing/boiling point of a salt solution is lower/higher respectively than pure water. Item-4 was used to find out whether students predict which solvent (water, ethanol and acetone) be used to prepare solutions of the solutes (sucrose, sodium sulphate, sodium chloride and iodine). To analyze the data, qualitative method was used and the subjects' responses were categorized separately in five understanding levels. The findings of this study showed that students have some difficulties to understand polarity of molecules, solubility and explanation of freezing or boiling point of solution