1. Balancing Chemical Equations

2. Conservation of Mass (Counting Atoms)
Step 1: Count the number of atoms on both sides of the equation (for the reagents and products). If it’s balanced, you don’t have to do anything!
2 NaCl + F NaF + Cl2

3. Conservation of Mass (Counting Atoms)
Step 1: Count the number of atoms on both sides of the equation (for the reagents and products). If it’s balanced, you don’t have to do anything!
FeCl33 + NaOH Fe(OH)3 + NaCl

4. Conservation of Mass (Counting Atoms)
Step 2: Add a coefficient in front of a molecule such that one element becomes balanced.
FeCl3 + NaOH Fe(OH)3 + NaCl

5. Conservation of Mass (Counting Atoms)
Step 3: If it is not fully balanced, add another coefficient to another molecule to bring another element into balance. Repeat until the equation is fully balanced.
FeCl3 + NaOH Fe(OH)3 + NaCl

6. Important Rules
You are only allowed to add coefficients, and they must appear at the front of the molecule… not in the middle!
Ex: H2SO H2SO4

7. Important Rules
No changing the subscript. This would change the molecule, which is not allowed. You can only change the quantity of each molecule.
Ex: H2SO H2SO4

9. One more important rules
Hate fractions? Good news, they’re NOT allowed as coefficients.
What should you do about this?

10. Tips
Sometimes you will only have to change one coefficient, and sometimes you will have to change several. This is normal. Keep going until it is perfectly balanced.
Sometimes you may have to adjust a coefficient more than once in the same equation. This is also normal. Keep going!

12. Workbook p. 21

14. What coefficient should go here?

15. C: C: 1
H: H: 2
O: O: 3
Tip #1
List all atoms neatly underneath each side of the equation, and count them up. Write them in the same order

16. 2
Tip #2
Notice the atoms are out of balance. Try to fix them one at a time. If we double the amount of CO2, we will balance the C’s.
C: C: 1 2
H: H: 2
O: O: 3 5

17. 2 3
Tip #3
Find the next atom imbalance that we can adjust. In this case, if we triple the amount of H2O, we will balance the H.
C: C: 1 2
H: H: 2 6
O: O:

18. 3 2 3
C: C: 1 2
H: H: 2 6
O: O:
Tip #4
Triple the amount of O2 on the reagents side. This will balance out the O’s.

19. Balanced! :) 3 2 3 C: 2 C: 1 2 H: 6 H: 2 6 O: 3 7 O: 3 5 7 Tip #4
Triple the amount of O2 on the reagents side. This will balance out the O’s.

20. Workbook p.19
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