Pictorial analogies that demonstrate concepts of amounts allow instructors to teach that in stoichiometric problems, the number--or moles--of molecules of a chemical is what matters, even though it must be measured in masses or volumes. Analogies to stoichiometric relationships include the ratio of four wheels to one body in making wagons and…

This unit on the mole is one of 10 first year units produced by the Independent Learning Project for Advanced Chemistry (ILPAC). The unit, designed to help students consolidate some of the ideas about the mole learned in previous courses, consists of two levels. The first level focuses on: (1) relative mass; (2) the concept of the mole as the unit…