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. In this program several "mole problems" are solved. There are actually two goals to achieve. We should improve our understanding of the quantities used in the calculations and improve our ability to "visualize" problems and to apply our understanding of quantitative reasoning to each "new" situation we encounter. This volume teaches how to improve your ability to "visualize" problems apply our understanding of quantitative reasoning. The quantities utilized in solving the mole problems are grams, moles and molecules. All moles contain the same number of particles, namely 6.02 x 1023. Moles of different substances will have different masses because some molecules are heavier than others.