Abstract: Addressing the common challenges in teaching fugacity—a core concept in chemical thermodynamics—such as its abstract nature, fragmented understanding, and disconnection from practical applications, this study proposes a progressive teaching reform approach grounded in the dynamic interplay of intermolecular attraction and repulsion forces. Departing from the traditional linear teaching model of definition-derivation-exercise, this approach reconstructs a comprehensive cognitive framework encompassing microscopic molecular essence, macroscopic thermodynamic phenomena, quantitative mathematical expressions, and practical engineering applications. A series of visualized teaching aids were designed to facilitate deep integration of abstract thermodynamic concepts with students' prior knowledge of molecular physics. Teaching practice results demonstrate that this reform approach significantly improves students' correct understanding rate of fugacity's essential connotation from 38.2% to 92.7%, while markedly enhancing their engineering application skills and scientific thinking competencies. This study provides a replicable model for reforming the teaching of core concepts in chemical thermodynamics.

Key words: Chemical thermodynamics, Fugacity, Intermolecular force, Teaching reform, Conceptual essence, Visualized teaching