This is a conceptual paper aimed at chemistry educators. The purpose of this paper is to illustrate the use of the semantic code of Legitimation Code Theory in chemistry teaching. Chemistry is an abstract subject which many students struggle to grasp. Legitimation Code Theory provides a way of separating out abstraction from complexity both of which provide substantial challenges to students. These are termed semantic gravity (degree of abstraction) and semantic density (degree of complexity). These ideas are then illustrated using chemical examples in order to demonstrate how they may aid the teaching of chemistry. There is a second pedagogical device which Maton, the developer of Legitimation Code Theory, calls "semantic waves". This is also discussed in the context of chemistry education. The semantic code could be applied to chemistry at all levels.