This study aims to identify and analyze processes of representation involved in Organic Chemistry didactics focused into undergraduate courses.

We consider semiotic representations as cognitive products whose meaning depends on use, as they intervene in intentional processes recognized and legitimated by a community (Araújo Neto, 2009).In a cognitive and semiotic perspective, one can understand that a representation is a notation that 're-presents' something for us, ie, it represents something in the absence of that object. Under the Social Semiotics, Mercer (1997) and Lemke(1997) consider learning as a semiotic science, ie a process of thinking that depends on the manner of language acquisition in the process of knowledge construction: learning to do science is essentially a sociolinguistic process. Classrooms are small social communities where meaning circulates; teaching science is therefore “teaching to use language" according to the semantic standards of science. Considering that meaning is formed within the same social group that it forms, in a dialectical interaction, and that it is expressed – and expresses itself - through oral, visual or written language, our proposal is to use the Peircean Semiotics as a method of interpretation of data, for its wide approach in understanding the phenomena, especially those that can be described by written, graphical, and visual language.

For Peirce, the sign pattern articulates qualities, events and processes and therefore can be interpreted as a relationship between these three elements. Signs are representations that allow the observation of the phenomenon (which present themselves to perception and mind) which, in turn, can be classified into three universal categories (Firstness, Secondness and Thirdness) identified by Peirce (2005). Semiotics is based on a triad of ratings and inferences, to demonstrate that there are objects in the world, their representations in the form of signs and mental interpretation of these objects. Therefore, in a semiotic approach, the representations can be interpreted considering the levels of relationships (meaning, objectification, interpretation) established by the signs and perceived by the students (interpreters), which implies experimental/empirical relationships or conceptual generalizations issued by them for their actions which make it possible to observe elements indicative of his thinking.

The chemical knowledge constitutes interpreted formal systems, implying that theoretical models, consisting in a body of statements, acquire content to be linked indirectly to aspects of the observable physical world of external reality. Interpretations lead to a theoretical model that pretends to be the actual representation of reality (Ferk, Blejec, Gril, 2003; Aduriz-Bravo, Galagovsky, 1997; Badillo-Gallego, 2004).Thus, the appropriate use of symbols constitutes a significant part of chemical knowledge and a deeper understanding about the meaning processes of chemical representations can influence student learning, given its peculiarities (structure and organization). Consequently, learning chemistry depends in large part on the student's ability to use language symbolic (representational) which requires some degree of abstraction (Engida, Barke, 2001).

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