A sistematização dos conceitos ácido-base e suas implicações para o processo de ensino-aprendizagem em química

Abstract

The general objective of this work is to contribute to the teaching-learning process of acid-base concepts through a proposal for the systematization of these concepts in order to minimize possible theoretical and conceptual confusions that may occur around them. The understanding of the teaching-learning process of acid-base concepts contributes to the systematization of chemistry, since they relate to and influence other concepts as supported by the History of Chemistry, the focus of the systematization of chemical thought. It was considered that systematizing involves organizing one concept in relation to another, i.e., by nature, a concept presupposes the existence of a certain system of concepts. This is an exploratory research, with a qualitative approach, aiming at the interpretation and analysis of papers published in chemistry journals, textbooks and national events in this area. The methodological procedure consisted of reading the selected texts, where we sought to identify which thematic categories could be the most representative to illustrate the problem detected: the perpetuation of theoretical-conceptual confusions. The analysis of the investigated works allowed the identification of the main theoretical-conceptual confusions around the acid-base concepts: (1) Acid, base, salt and oxide: functions of inorganic chemistry? (2) Disjointed classification rules; (3) Disjointness between acid-base theories or absence of acid-base theory; (4) Generalized chemical reaction: acid + base → salt + water; and finally, (5) Lack of contextualization. The results of this research showed that, to a large extent, the first theoretical-conceptual confusion - focus of the textbook and teaching journal analysis - is still perpetuated among the analyzed works. The indiscriminate use of the term "inorganic functions" to classify substances with an acid-base character, as well as salts and oxides, was verified in some works. This shows that this research problem has not yet been solved within the community of chemical educators. In this thesis, I seek to argue that the theoretical-conceptual confusions are not only problems that were identified from the analyzed works; it is a historical problem, that is, the acid-base concepts go through history in such a way that their understanding is confused with the very origin of Chemistry. I believe that the biggest problem is the dogmatization of scientific knowledge, that is, the acid-base concepts are, in a way, transferred without the presentation of their origins, without their development - in short, without their construction or elaboration and in a confusing way. A proposal for the systematization of acid-base concepts was elaborated as a possible approach for the teaching of chemistry.