El principio de Le Chatelier a través de la historia y su formulación didáctica en la enseñanza del equilibrio químico

摘要

The historical evolution of the Le Chatelier's principle is connected with its use in the chemistry classroom. The apparent simplicity in which the Le Chatelier's principle was first formulated and the success achieved in the implementation of some important industrial processes gave it an initial acknowledgement still kept nowadays. Nevertheless, since the beginning of this century, different authors have pointed out the limited character of the qualitative rule and its vague and ambiguous formulation. Furthermore, thermodynamics gives for the Le Chatelier's principle some quantitative formulations that limit its applicability. However, most general chemistry textbooks have treated the Le Chatelier's qualitative rule as a universal and infallible principle, making suitable for teaching the statement given by Le Chatelier in 1888. This didactic teaching approach is a source of different misconceptions which are generated in the prediction of the evolution of a perturbed chemical equilibrium system. Hence, some authors have suggested avoiding the Le Chatelier's rule. This new option assumes to use exclusively the chemical equilibrium constant.