Ensino de eletroquímica no ensino médio por meio de uma proposta didática com abordagem de equilíbrios simultâneos de oxirredução e de complexação

Abstract

Electrochemistry is a content that involves difficulty in the teaching and learning process, both in high school and college. Aiming to contribute to the teaching of electrochemistry concepts in basic education, a sequence of classes based on digital technologies, computer simulation and experimentation was used, using an experimental kit made from a question of the 2019 entrance exam from the Instituto Militar de Engenharia (IME), tools that can facilitate the teaching of these concepts, allowing an association between three representational levels: macroscopic, microscopic and symbolic. The work was developed in a State College of the Military Police, in the city of Itumbiara-GO, during the COVID-19 pandemic, with remote classes. However, with the gradual in person return, after almost two years of remote classes, the experimental activity was carried out in person. The didactic proposal was developed with the participation of 11 students from the 2nd year of high school (except in the face-to-face experimental activity, where 7 students participated), during 11 50- minute classes, taught in september and october 2021, outside the students' regular class hours. The activities were carried out in the following sequence: i) diagnosis of the students' knowledge in electrochemistry, through the application of three instruments; ii) classes using powerpoint slides containing theoretical aspects of electrochemistry and chemical equilibrium; iii) use of a simulator, focusing on the galvanic cell known as Daniell's Cell and evaluation of the activity; iv) resolution of the highly complex IME-2019 entrance exam question, which inspired the making of the experimental kit, assembly and use of the electrochemistry experimental kit and activity evaluation; and v) reapplication of the three instruments of item i), which made it possible to evaluate the efficiency of the didactic proposal in the teaching-learning process of the students. The results obtained indicate the efficiency of the didactic proposal in the teaching-learning process of the students, as there was an improvement in their performance in all instruments, comparing the two moments of its application, that is, before and after the development of the didactic proposal. This shows evidence that computer simulation and experimentation are pedagogical resources that can complement each other and, when associated with traditional lectures, can lead to an improvement in the teaching-learning process of chemistry content in basic education. Thus, through diversified classes, it becomes possible for the teacher to explore various concepts, such as oxide-reduction reaction, complexation reaction, galvanic cell, Nernst equation, equilibrium constant, among others. It is important to emphasize that the experimental kit developed in this work is easily reproducible, made with easily accessible, low-cost materials that can be used as a didactic tool to enhance the teaching and learning process. This experimental kit consists of the educational product of this dissertation, and was accepted for publication in the Experimentation in Chemistry Teaching section of the journal Química Nova na Escola (QNEsc).