Teaching Stoichiometry with Particulate Diagrams – Linking Macro Phenomena and Chemical Equations

Abstract

This chapter explores a way stoichiometry is introduced to secondary school students that aims at fostering a conceptual understanding and a relational understanding of the chemistry triplet (i.e. macro, submicro and symbolic). We start by discussing students’ difficulties in understanding macro phenomena, submicro and symbolic representations that are relevant to the learning of stoichiometry. Then we argue that a teaching sequence starting with macro phenomena, then a submicro representation of the corresponding macro phenomena, and finally deriving a chemical equation based on the submicro representation, should be likely to facilitate students’ understanding of stoichiometry. Strategies that guide the selection of a particular macro phenomenon and diagrammatic representation of submicro interactions are proposed. We then analyze a lesson that was conducted based on the design. Particularly, we focus on good practice of teaching with diagrammatic representation of submicro phenomena that served to link macro phenomena and chemical equations as symbolic representations.