The concept of substance is considered fundamental in order to understand chemistry and other related concepts, but many problems have been reported about its learning process. Considering the importance of textbooks in the training of chemistry teachers, this study aimed to identify the concepts of substance in general chemistry textbook glossaries. In addition, the study assessed the concepts of substance in relation to other chemical concepts and, when available, compared them with the concepts established by the IUPAC. The methodology employed (...) was content analysis and the results showed that concepts and statements related to the term ‘substance’ are different in the general chemistry textbooks analyzed. They also differ from those stated by IUPAC. Furthermore, it was found that many concepts are dependent on the concept of substance. It is concluded that there must be a greater effort from the community of chemists and the teaching of chemistry in the search for conceptual uniformity to reduce the problems of conceptual understanding. (shrink)

A new chronology is introduced to address the history of chemistry, with educational purposes, particularly for the end of the twentieth century and here identified as the fifth chemical revolution. Each revolution are considered in terms of the Kuhnian notion of ‘exemplar,’ rather than ‘paradigm.’ This approach enables the incorporation of instruments, as well as concepts and the rise of new subdisciplines into the revolutionary process and provides a more adequate representation of such periods of development and consolidation. The fifth (...) revolution developed from 1973 to 1999 and is characterized by a deep transformation in the very heart of chemistry. That is to say, the size and type of objects, the way in which they must be done and the time in which they are transformed. In one way or another, chemistry’ limits had been set out. (shrink)