Contextualização da química ambiental no ensino médio a partir da construção de um titulador automático controlado por arduino para análises da acidez em água de Parintins-AM

Abstract

In quantitative chemistry, volumetric methods are widely used to characterize and determine the concentration of an analyte. The volumetric titration technique is based on the complete reaction of a known volume of a sample with a determined volume of a reagent of known nature and concentration, called standard solution, being defined as titrant and the solution whose concentration is to be determined designates himself by title. Volumetric titration is a method widely used by chemists for the determination and characterization of samples for a long time. Among the volumetric methods, the acid-base titration stands out, the focus of this work. However, the acid-base determination process has been generating handling problems, such as the turning point outside the determined time and the use of toxic indicators. Thus, the automatic titrator is an alternative for more accurate and reliable analysis, this analytical instrument is based on the movement of the piston with a synchronous motor - peristaltic pump - with the aid of an Arduino UNO board and IDE programming, a software responsible for communication of the computer program. In this context, the objective of this work is to develop an automatic titrator with the aid of an Arduino UNO board to determine the acidity of water in different locations in Parintins, proposing to evaluate the quality and accuracy of the use of software to replace manual work in the laboratory. with the validation of the method with potentiometric titration and its application in experimental teaching of Environmental Chemistry for high school students. In this work, it was demonstrated that the automatic titrator, in addition to being easy to acquire/build and low cost, can execute the commands and perform more accurate analyzes when compared to the traditional titrator. The standardizations performed with the automatic titrator were compared with the classic titration, and this did not present significant differences with the application of the t test close to 95% confidence. In addition, this prototype can be developed and applied in the context of the school environment for a more meaningful student learning, enabling the study with pH measurements as a didactic activity. Experimentation in teaching chemistry is considered an alternative approach to teaching chemistry. According to the literature reviews on the subject, there are several perspectives and obstacles to experimental teaching. And even with the challenges of inserting the experimental class in the school environment, it is important for educators to overcome this barrier. Because experimentation in teaching chemistry is capable of strengthening the student's learning process. And as perspectives of this work, a larger study with the automatic titration is necessary for the deepening about the possibilities of the use of this prototype, as well as the development of other chemistry projects involving the Arduino as a new alternative in the construction of projects.