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 we will see how Le Chatelier's Principle can be used to predict the effect of a change in pressure or temperature on an equilibrium system. This volume teaches the change in the amounts of reactants and products can be unambiguously predicted by Le Chatelier's Principle. That pressure changes are only relevant to equilibriums systems that contain at least one gaseous reactant of product. If we increase the pressure on the system, the system will try to decrease the pressure, and vice-versa. If a system contains the same number of gaseous molecules on both sides of the equation, it cannot respond to a change in pressure.