摘要：Chemistry textbooks have a great influence in teaching and learning. In this work, an analysis is carried out about the definitions of basic chemical concepts presented in twenty textbooks mostly utilized by argentine teachers. The concepts revisited were: objective of chemistry study, substance, chemical reaction, elementary substance, element, compound, atom, molecule and ion. The author has preoccupation of the results with regard to: (1) the diversity and ambiguity of the definitions, (2) the absence of coincidences between textbooks, (3) the little internal coherence of discourse, (4) the promotion of alternative conceptions, (5) the relationship between macroscopic and microscopic levels, and (6) the scarce precaution in the introduction of historical information. A proposition about the definition of each of the surveyed concepts has been added in italics.
关键词：definitions; basic chemical concepts; secondary textbooks; alternative conceptions
