This article outlines a procedure that was used to develop a written test for evaluating the conceptual knowledge of chemical equilibrium constant among university students. The concepts in the subject matter were carefully defined through propositional statements. Students' understanding of the topic was determined through interviews. These data were used to produce nine multiple choice questions. Each question was designed to identify misconceptions related to the chemical equilibrium constant. The test was evaluated by foure associate professors and was administred to a total of 196 spanish university students. This test has a Cronbach's alpha reliability of 0.63 and its content validity values ranged from 3.7 to 5.

In this study we investigated alternative conceptions about galvanic cells and interpretations of the process occurring in a voltaic cell. It was conducted with fifty-five 12th grade high school students and forty-three first-year university chemistry students. Comparative analysis of the results obtained by means of a test and an open question reveals that: a) Many high school and university students hold misconceptions about galvanic cells; b) There is no significant difference in misconceptions and interpretations between the two groups of students, and c) Few students can correctly explain how a voltaic cell works. Finally, the implications of these results are discussed.

En el presente trabajo se han investigado las concepciones alternativas sobre pilas galvánicas y las interpretaciones de los procesos que tienen lugar en una pila voltaica simple. Han participado en él 55 estudiantes del 2° de Bachillerato español (curso previo al ingreso en la universidad) y 43 estudiantes de primer año del Grado de Química. El análisis comparativo de los resultados de la administración de un test y de una pregunta abierta revela que: a) Tanto los estudiantes de 2° de Bachillerato como los de 1° de Grado sostienen concepciones erróneas sobre pilas galvánicas; b) No hay diferencias significativas en las concepciones e interpretaciones entre ambos grupos de estudiantes, y c) Pocos estudiantes son capaces de explicar cómo funciona una pila voltaica simple. Finalmente, se discuten las implicaciones que tienen estos resultados.