Interações intermoleculares e o fenômeno da solubilidade: explicações de graduandos em Química

Abstract

The present study investigated the use of intermolecular interaction concepts by freshman chemistry students during general chemistry classes, explaining some of the solubility phenomenon. For this purpose, classes on the topic in question were monitored and two tests were asking for explanations for the difference in solubility of oxygen and carbon dioxide in water and in perfluorocarbons and oxygen in fresh or salt water. Students also made graphic representations showing the water - oxygen molecules interactions. An analysis of the data demonstrated that several students had difficulties in correctly identifying that intermolecular interactions are involved in these systems. The concept of polarizability, fundamental in these systems, was rarely used in their explanations. The answers also indicated extensive use of the “like dissolves like” rule to explain solubility rather than using a complete description of the interactive processes involved. Most of the students’ explanations suggest an understanding of the knowledge as data or fact reproducing information and ideas without an effective use and understanding of the chemical concepts.