Resumen: Una clase de química puede ser considerada como un espacio de comunicación entre el docente experto y los estudiantes novatos, donde los lenguajes utilizados son la interfase explícita y observable del intercambio comunicativo. En el presente trabajo se muestra con dos ejemplos cómo la diversidad de lenguajes químicos en lugar de favorecer la comprensión de los estudiantes, puede actuar como fuente de obstáculos que dificultan la comunicación en el aula. Así mismo, se analizará con otros dos ejemplos cómo el discurso con el que se enseña la disciplina también es potencial generador de errores en los estudiantes, cuando ellos construyen sus modelos mentales idiosincrásicos a partir de un discurso recortado y simplificado, desde las mejores intenciones de realizar buenas transposiciones didácticas. Se plantea que un enfoque de análisis de la situación de aula como un encuentro comunicativo entre experto y novato conduce a una necesaria diferenciación entre "hablar química" y "comprender química".Palabras clave: Enseñanza de química. Comunicación. Discurso. Didáctica. Aprendizaje. Abstract:A class of chemistry can be considered as a forum for communication between the expert teacher and novice students, where the languages used are explicit and observable interface of a communicative exchange. In this paper we show, with two examples, how the diversity of chemical languages, instead of promoting student understanding, it can act as a source of barriers to communication in the classroom. Also, will be discussed in two examples how the speech with which the discipline is taught is also generating potential errors in students when they build their idiosyncratic mental models from a cut and simplified speech from the best intentions of make good didactic transpositions. It is argued that an approach to analysis of the situation in the classroom as a communicative encounter between expert and novice leads to a necessary distinction between "talking chemistry" and "understanding chemistry."

Hydrophobic interaction chromatography was employed for the fractionation of the glycopeptide mixture obtained after autoproteolysis and delipidization treatment of normal human seminal plasma samples. This sequence of procedures led to the elimination of highly hydrophobic components and to the concentration of the carbohydrate-rich fractions. A partial separation between the O- and N-glycosidic-linked oligopeptides was also achieved after the chromatographic step.

En el presente trabajo se analiza el tema estequiometría, en su relación con la Ley de Conservación de la Masa, desde la perspectiva de análisis comunicacional en el aula de química para la interpretación de errores de los estudiantes. La revisión del discurso docente a través de libros de textos permite reflexionar sobre los significados otorgados por los docentes a los términos “reacción química”, “reactivos” y “productos”, y sobre qué podrían comprender los estudiantes, cuando se omiten reflexiones históricas y epistemológicas sobre dichos términos.

The aim of the work in hand is to come to conclusions as to why students relate boiling points of substances, such as halogens, with their atomic properties. The fact that this mistake has been observed in many evaluations brought about the implementation of a specific test to find out whether the students know that the boiling point is a macroscopic property of an elemental substance as in this case and not an atomic property.As the energy associated with a physical change is generally much lower than the one related to chemical bond breaking, the test also included a question aimed at finding out if students are able to differentiate between physical and chemical properties. It is thought that this could be helpful for them to relate boiling points to strength of intermolecular forces, and therefore overcome one of the most common alternative conceptions associated with this subject.Finally, in view of the different interpretations of the word "chlorine", used on an equal basis for the atom, the molecule and the elemental substance, the test provided a way to detect whether students that have already studied the subject of chemical bonds, are able to relate experimental data, state of matter and atomicity of chlorine; that is, that they can relate submicroscopic and macroscopic states.The analysis of the obtained results allows the identification of difficulties the students are faced with in this subject and the interpretation of possible causes.