Chemistry - the Complete Course Series, teaches students quantitative reasoning to solve chemistry problems. The 30 volume series covers all aspects of Chemistry from density to the mole, to molarity, stoichiometry and equilibrium. It demonstrates how to ask meaningful questions and conduct careful investigations to build knowledge of chemical and physical concepts and develop the skills to solve mathematical and scientific problems. One of the most important concepts to master is the concept of the mole. Before you can begin to develop an understanding of the mole concept, it is necessary to master simpler concepts. Included among these concepts are things like the meaning of the terms atoms, molecules, ions, and formula units. This volume teaches the meanings of things such as symbols and formulas, and to interpret the formulas of substances. Atomic weights represent the relative weights of different atoms. Atomic, molecular & formula weights are expressed in atomic mass units.