Les difficultés rencontrées dans l’apprentissage du concept de concentration en chimie. Construction d’un outil didactique permettant de mettre en évidence les erreurs d’élèves lors de l’utilisation du concept de concentration chimique

Abstract

The concentration of a solute in a solution is a central concept in chemistry that comes up throughout the whole curriculum. A lot of difficulties prevent the learners from gaining an expert acquisition. The transfer of this concept in new situations is therefore very complicated or even impossible. This research is situated in the theoretical framework of conceptual change completed by results of neuroscientific studies. Open and multiple-choice questionnaires have been submitted to French-speaking students from Belgian schools (degree 10 to 12) to bring out the learners’ conceptions faced with the concept of chemical concentration. The analysis of the results highlights the most frequently committed errors. The most recurrent ones are those connected to the intensive nature of the chemical concentration and those linked with the confusion between the volume of the solvent and that of the solution. Individual interviews enable us to clarify the main dysfunctions at the origin of these errors. A didactic tool for self-assessment has been elaborated to enable students to identify quickly the type of errors they commit and move towards an adapted remediation.