1. Writing Balanced Chemical Equations

2. Law of Conservation of Mass In normal chemical processes (non- nuclear) mass can be neither created nor destroyed. Application: The numbers and types of atoms must be exactly the same on both sides of the chemical equation. mass before rxn = mass after rxn

3. Step 1 Determine formulas of all reactants and products using the rules of nomenclature and their required oxidation states.

4. Step 2 Classify the Reaction as… Single displacement Double displacement Combustion Synthesis Decomposition

5. Step 3 Use proper notation to write an unbalanced equation. Reactants to the left Products to the right Reactants → Products Symbols: → yields (s) solid (l) liquid (g) gas (aq) aqueous – means water solution (cr) crystalline Up or down arrows to indicate gas evolved or precipitate (g)  or (s) ↓ Indicate special conditions above the yields sign Acid, base, catalysts, heat, temperature, acidic, basic

6. Step 4 Balance using the following rules Do not change subscripts after you have determined proper formulas Change only coefficients Do not insert coefficients within a chemical formula Reduce coefficients to lowest terms

7. Rules of Thumb Balance free elements last Balance oxygen last Focus on only one element at a time Balance polyatomic ions as a unit if possible Use fractional coefficients if helpful, but remember to multiply the entire equation by 2 to get rid of the fractions