1. Balanced Chemical Equations C O OC O C O O O C O

2. The Law of Conservation of Mass: In any chemical reaction matter cannot be created or destroyed. We call this equation unbalanced because the atoms are not conserved. H 2 (g) + O 2 (g) H 2 O (g) H O HHH O 22 HH O HH O

3. Balancing Rules: 1.You cannot change a formula. (what it is) H2OH2O3 3 2. You can ONLY add a coefficient. (how many there are)

4. 2 a. Coefficients can only be placed in front. You can write 2 H 2 O, but not H 2 2O. 2 b. Coefficients apply to the whole molecule. H2OH2O3

5. BALANCING STEPS: 1.Determine the number of atoms for each element in reactants and products. 2. Balance metals first, then non-metals. 3.Balance single elements last. 4.Check and recount all the atoms. Use trial and Error.

6. C + O 2 CO 2C: 1 O: 2 BALANCED

7. HCl + MgBr 2 MgCl 2 + HBr H: 1H: 1 Cl: 1 Cl: 2 Mg: 1 Br: 2 Br: 1 BALANCED 2 (2) = 2 2

8. CH 4 + O 2 CO 2 + H 2 O C: 1 H: 4 H: 2 O: 2 O: 2 + 1 BALANCED 2 (2) = 4 2

9. K(NO 3 ) + Mg Mg(NO 3 ) 2 + K K: 1K: 1 NO 3 : 1 NO 3 : 2 Mg: 1 BALANCED 2 (2) = 2 2

10. Balancing Word Equations

11. Step 1: Write reactant and products using the symbols + and Step 2: Write correct formula for reactant and product (skeleton equation) Step 3: Next we have to balance the equation Step 4: Complete the equation by adding all states (solid, liquid, gas)

12. Solid aluminum and nitrogen gas react to produce solid aluminum nitride. aluminum nitrogen aluminum nitride Al + N AlN (s)(g) (s) 2 22 + +3 -3

13. Solid potassium iodide and chlorine gas react to produce potassium chloride and liquid iodine. potassium iodide chlorine potassium chloride KI + Cl KCl + I (s)(g) (l)2 2 2 + +1 -1 iodine + +1 -1 2

14. Methane gas and oxygen gas react to produce carbon dioxide gas and water. methane oxygen carbon dioxide CH 4 + O CO 2 + H 2 O (g) (l)2 2 2 + water + (g)

15.  explain the Law of Conservation of Mass  differentiate between subscripts and coefficients  balance skeleton equations by adding coefficients  translate word equations into balanced chemical reactions  translate balanced chemical reactions into word equations