Stoichiometry is one of the most major branches in chemistry that deals with the relative qualities and quantities of reactants and products in chemical reactions. Stoichiometry is based on the Law of Conservation of Mass. Stoichiometry is broke into the subjects of: Reaction Stoichiometry and Composition Stoichiometry. Reaction Stoichiometry describe relationships of substances during a chemical reaction. Composition Stoichiometry describes the quantitative mass among elements and its relationship with compounds. Next their is Gas Stoichiometry which is part of Reaction Stoichiometry. Gas Stoichiometry involves chemicals and compounds in its relationship that involves gases, such as steam or burning magnesium. The term Stoichiometry itself derives from the greek word, stoicheion metron, which means element measure or measurement of an element. Stoichiometry relies on scientific laws in chemistry to understand things better. The main use of Stoichiometry is to balance equations in chemical reactants.