Learning about molecular structures often becomes abstruse, due to its complex compositions, being aggravated by the restricted interactivity provided by the software commonly used. This difficulty can also be attached to the fact that most of the students do not present the necessary knowledge to work with biomolecular systems, affecting also the motivation in the object of study. In this context, the objective of this work is to analyze the influences related to interactivity, usability and motivation, provided by a web system called MMAR (Molecular Modeling with Augmented Reality), designed to support the learning of three-dimensional (3D) molecular structures. The system was applied to twenty-five students in the Chemistry discipline, from a technical course in a public school from basic education in Brazil. The results show that it was possible to assist students in the gain of knowledge, while simultaneously allowing them to enjoy themselves, providing unconventional learning, by increasing attractiveness, curiosity, attention, enthusiasm and relevance of such a complex subject in Chemistry.