Where is the thermochemistry that was here? Analysis of thermochemistry content in a collection of didatic books

Abstract

The National Common Curricular Base (BNCC) is the official document that guides the Brazilian basic education curriculum and, as a normative document, the BNCC pedagogical foundations also influence teaching materials. Understanding textbooks as an important instrument for accessing systematized knowledge, the objective of the research was to analyze the thermochemistry content in the collections Ser Protagonista for the Chemistry discipline or the Natural Sciences area, for highschool education, of the Programa Nacional do Livro e Material Didático (PNLD) in 2018 and 2021. The thermochemistry contents in each volume of the collections were identified through a keyword search. Afterwards, the contents were analyzed considering: the adequate definition of concepts, use of examples, the importance of thermochemical calculations and Hess's Law as a particular case of the first law of thermodynamics. The analysis was carried out in a comparative way, relating the changes in textbooks with the BNCC curricular guidelines. The analysis demonstrated that the 2018 PNLD collection presents an inadequate concept of enthalpy and approaches Hess's Law as a purely mathematical discussion. The analysis also showed that the 2021 PNLD collection, despite a chapter dedicated to thermodynamics, with the definition of important concepts such as heat and internal energy, absent in the previous collection, there is a predominance of the physical approach in this content and the absence of the study of thermal effects associated with chemical reactions. Based on the results found, we consider that, in the new collection, guided by BNCC, there was a suppression in the thermochemistry content in the Ser Protagonista collection of PNLD 2021, prejudicial to the student in their human formation.