Chapter 3: Molecules and Chem Equations Section 3.2: Chemical Formulas and Equations Monday, September 8, 2014 2:44 PM Chemical Equations: symbolic representation of a chemical reaction Left side: reactants (original materials) Right side: products (compounds formed from reaction) ? Notation: Reaction w/ heat is indicated by delta Reaction w/ light energy is indicated by hv (called a photochemical reaction) ? Hints: Balance elements that occur in only one compound on each side first Balance free elements last Balance polyatomic ions as groups ? Balancing Chemical Equations Remember LAW OF CONSERVATION OF MATTER Stoichiometry: study of relationships between reactants and products in a chemical reaction (numbers in chem equations are stoichiometric coefficients) ?