This article is the result of an investigation conducted in 2012, whose main objective is to use the labs as a teaching strategy from the constructivist paradigm that promotes the construction of school scientific knowledge. The methodological approach is qualitative research. The study sample group contained 8 eleventh graders randomly chosen. 4 times in the methodology were implemented in the first test were performed to identify the previous ideas of students; in the second laboratory guidelines and practices they were designed taking into account the levels of openness, then applying the same was done at the last moment and the corresponding qualitative analysis was developed. As a result it is evident that in the development of practical motivation and interest in the process was higher in students, which contributed to the development of certain scientific skills, the results of the post test were significant, it was possible to strengthen students the skills and understanding of concepts related to the topic of chemical reactions. The investigation can be concluded that laboratory practices conceived as a teaching strategy for teaching and learning of chemical reactions allowed the development of some scientific skills and a more meaningful learning of concepts associated with the topic in students