1. Balancing Chemical Equations

2. Parts of a Chemical Equation What is a chemical equation? It is a way to symbolize what is happening in a chemical reaction. There are basic parts to a chemical equation. Reactants Products Coefficient Subscript “Yields” Arrow A + 2B  AB 2

3. Coefficients vs. Subscripts A coefficient tells you how many SEPARATE atoms or molecules you have. Example: 2Fe (Means I have two SEPARATE atoms of Iron) A subscript tells you how many atoms are BONDED together. Example: O 2 (Means I have two oxygen atoms BONDED together) Fe OO

4. What if I have 2H 2 This means I have two molecules of H 2 Multiply the coefficient by the subscript 2 x 2 = 4 Hydrogen Atoms H H HH

5. Let’s Practice Counting How Many See the Worksheet….

6. Time to Balance Why balance? The Law of Conservation of Matter Matter cannot be created or destroyed. If I start with 2 Oxygens, I should end with 2…was matter destroyed? No…the equation just has to be balanced! H 2 + O 2  H 2 O

7. Add Coefficients Coefficients can be changed NEVER change subscripts – this changes the identity of the substance Add coefficients until the left side of the reaction equals the right side of the reaction. H 2 + O 2  H 2 O H = O = We need more Oxygen…add a coefficient on the right Now the number of Hydrogen changes Add a coefficient on the left side 22 2 4 42 2 2 1

8. One More Example Rb + P  Rb 3 P Rb = P = Rb needs to be balanced. Add coefficients to the left side. 3 31 11 3

9. Time to Practice!