The hypothesis that a better representation of energy is important to help students understand the founding knowledge in chemical thermodynamics is formulated. A simple model is used to help students with such a representation: as the chain energy model. The benefit of this model can be anticipated on the basis of the known pre-university students’ conceptions, which are reviewed in this article. An innovative teaching sequence involving the chain energy model is then designed, analyzed and evaluated. This teaching sequence involves an experimental work and a computer simulation to introduce chemical thermodynamic concepts such as bonding energy, heat of reaction or changes of states, from both microscopic and macroscopic viewpoints.