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. Equilibrium systems are very changeable. By altering conditions such as the concentration, the pressure or the temperature, we often can cause the system to establish a new equilibrium with different concentrations of reactants and products. Le Chatelier's Principle usually allows US to answer several important questions regarding what will happen to an equilibrium system when the conditions of the system are changed. This volume teaches a simple way to state Le Chatelier's Principle is to say that whatever you do to a system at equilibrium, it will try to do the opposite. If a stress is applied to a system at equilibrium, the system will shift. Le Chatelier's Principle is an extremely useful qualitative tool in chemistry.