1. Chemical Equations

2. The “sentences” of chemistry Show how elements react with each other and what compounds they will form So that’s what happens when sodium and water mix!!!!

3. Parts of a chemical Equation Reactants Always on the left of the equation What the reaction STARTS with Products Always on the right of the equation What is produced from the reaction (made) Yield= Where the reaction actually occurs

4. Can you show me what you just said??? Mg + O 2  MgO ReactantsProducts Yield Sign

5. Law of Conservation of Mass The reason we balance reactions Matter is neither created nor destroyed You must account for all elements before and after reaction Who came up with this law? Antoine-Laurent de Lavoisier was the first to state this law.

6. Rules for Balancing equations 1.Inventory first 2.Locate one element that does not balance 3.Add a coefficient to make it balance NEVER TOUCH A SUBSCRIPT 4.Look to make odd numbers even 5.Re inventory 6.Repeat until balanced KClO 3  KCl + O 2 It’s best to leave H and O for the end

7. Balancing Example: Mg + O 2  MgO 1Mg 1 2 O 1 2 2 2 / / 2

8. Practice Problems Balance the following reactions: P 4 + O 2  P 4 O 10 Zn + HCl  ZnCl 2 + H 2 Ca + O 2  CaO NaClO 3  NaCl + O 2 5 2 2 2 2 2 3

9. Diatomic Molecules Memorize these Br I N Cl H O F When these elements are in there pure state they only exist as PAIRS.

10. Questions