1. February 18 th, 2016 Balancing Equations Introduction

2. Products Reactants Coefficient Arrow Atoms Molecules Diatomic Molecules Catalyst Subscripts Law of Conservation of Mass Phases (g), (l), (aq), (s)

3. Chemical Reaction (CH 3 ) 2 CHOH (l) Isopropyl Alcohol (CH 3 ) 2 CHOH (l) + O 2 (g) ----> CO 2 (g) + H 2 O 2 (CH 3 ) 2 CHOH (l) + 9 O 2 (g) ----> 6 CO 2 (g) + 8 H 2 O

5. A 2 + 3BA2B3A2B3 Balancing Equations can be fun yet tough! This presentation will provide you some helpful tricks.

6. Chemical Reactions Chemical Reaction (rxn): Atom arrangement is changed. (Bonds are formed or broken) Chemical Equation: Shorthand notation describing what has taken place in a rxn.

7. Chemical Reactions Reactants: Beginning substances Products: Ending substances Reactants Products Yields

8. Chemical Reactions Phases of Matter: Solid (s) Liquid (l) Gas (g) Aqueous Solution (aq) -solids dissolved in water solution

9. Chemical Reactions Catalyst: Speed up a reaction, but are not used up in the reaction & are shown above the arrow Reactants Products A + B AB

10. Chemical Reactions Law of the Conservation of Matter: Matter is not created nor destroyed, but conserved in any chemical reaction Must have same # of elements on both sides of the reaction.

11. Chemical Reactions Coefficients: Numbers placed in front of a formula, used to balance HgO Hg + O 2 Reactants Products 22

12. Chemical Reactions H 2 O (l) H 2 + O 2 Notice that as it stands, we have one oxygen on the reactants side and two oxygen atoms on the product side of the equation. 2 Adding a coefficient “2” in front of H 2 O corrects our oxygen problem, but now causes Hydrogen to be unbalanced... 2 Adding a coefficient “2” in front of H 2 corrects our unbalanced hydrogen problem. We now have the same number of hydrogen and oxygen atoms…It’s balanced!

13. Chemical Reactions H 2 O (l) H 2 + O 2 Notice that as it stands, we have one oxygen on the reactants side and two oxygen atoms on the product side of the equation. 22 Reactants H = 2 O = 1 Products H = 2 O = 2 Unbalanced 2 4 4

14. Chemical Reactions Cu + AgNO 3 Cu(NO 3 ) 2 + Ag It is helpful to list the atoms involved and find out what is balanced and what is unbalanced (Hint = Polyatomic ions stay together!) Reactants Cu = 1 Ag = 1 NO 3 = 1. Products Cu = 1 Ag = 1 NO 3 = 2. Unbalanced 2 2 2 2 2

15. Chemical Reactions F 2 + H 2 O HF + O 2 Reactants F = 2 H = 2 O = 1. Products F = 1 H = 1 O = 2. Try this one on your own! Unbalanced 2 2 4 4 4 4 2 4 Balanced!

16. Try this on your own and then learn a great trick NH 3 + O 2 N 2 O 4 + H 2 O Reactants N = 1 H = 3 O = 2. Products N = 2 H = 2 O = 5. 2 2 6 6 3 7 The only way to make 2 oxygen atoms into 7 oxygen atoms is to have a coefficient of 3.5. This is not acceptable. 3.5 Hint: Double all coefficients except the “problem”. 4 4 12 2 4 11 6 12 14 Now there are an even # of product oxygen atoms 7 14