Research on learning difficulties associated with thermodynamics is well documented. These studies have characterized student conceptions of energy,1 phase changes, 2.3 equilibrium, 4-7 and the second law of thermodynamics. 8-10 Comprehensive reviews covering students’ conceptual difficulties about several thermodynamic ideas such as chemical equilibrium, 7 chemical energetic, chemical thermodynamics,1 and entropy 11 establish that students have significant learning difficulties with thermodynamics.presentation of Gibbs energy would be far beyond an introductory chemistry level and (ii) current attempts to introduce those difficult concepts in first-year university chemistry courses are usually full of misleading formulations.