Balancing

1. BALANCING CHEMICAL
EQUATIONS

2. Balancing Chemical Equations
H2O2  H2O + O2
H
O
2
2
H
O
2
3

3. Balancing Chemical Equations
H2O2  2H2O + O2
H
O
2
2
H
O
4
4

4. Balancing Chemical Equations
2H2O2  2H2O + O2
H
O
4
4
H
O
4
4
BALANCED!!!

5. Balancing Chemical Equations
RE-DO:
H2O2  H2O + O2
H
O
2
2
H
O
2
3
You may be tempted to put a 3 in
front of the H2O2…let’s try that!

6. Balancing Chemical Equations
RE-DO:
3H2O2  H2O + O2
H
O
6
6
H
O
2
3

7. Balancing Chemical Equations
RE-DO:
3H2O2  3H2O + O2
H
O
6
6
H
O
6
5

8. Balancing Chemical Equations
RE-DO:
15H2O2  18H2O + O2
H
O
30
30
H
O
32
20
GETS HARDER AND HARDER!!!!!!!
If it doesn’t seem to work, start again using DIFFERENT coefficients

9. Balancing Chemical Equations
H2O2  H2O + O2
H
O
2
2
H
O
2
3
When you see an odd number, just multiply
the compound that is making the number odd
by 2 to make it even, and easier to work with
2
X 4
X 4

10. Balancing Chemical Equations
CaSO4 + KOH  Ca(OH)2 + K2SO4
Ca
SO4
K
OH
1
1
1
1
Ca
SO4
K
OH
1
1
2
2
Polyatomic ions!!!!
You can think of polyatomic ions as INDIVIDUAL
elements when completing the chart

11. Balancing Chemical Equations
CaSO4 + 2KOH  Ca(OH)2 + K2SO4
Ca
SO4
K
OH
1
1
2
2
Ca
SO4
K
OH
1
1
2
2

12. Balancing Chemical Equations
CaSO4 + 2KOH  Ca(OH)2 + K2SO4
Ca
SO4
K
OH
1
1
2
2
Ca
SO4
K
OH
1
1
2
2
BALANCED!!!

13. Balancing Chemical Equations
H3PO4 + NaOH  H2O + Na3PO4
You can pretend that each polyatomic ion is an
INDIVIDUAL element when making the chart

14. Balancing Chemical Equations
H3PO4 + NaOH  H2O + Na3PO4
H
PO4
Na
O
4
1
1
1
H
PO4
Na
O
2
1
3
1

15. Balancing Chemical Equations
H3PO4 + 3NaOH  H2O + Na3PO4
H
PO4
Na
O
6
1
3
3
H
PO4
Na
O
2
1
3
1

16. Balancing Chemical Equations
H3PO4 + 3NaOH  3H2O + Na3PO4
H
PO4
Na
O
6
1
3
3
H
PO4
Na
O
6
1
3
3
BALANCED!!!

17. Balancing Chemical Equations
BaCl2 + (NH4)2CO3  BaCO3 + NH4Cl
You can substitute each polyatomic ion with an X, Y, or Z
to make life a little easier…
BaCl2 + (NH4)2CO3  BaCO3 + NH4Cl
X Y

18. Balancing Chemical Equations
BaCl2 + (X)2Y  BaY + XCl
Ba
Cl
X
Y
1
2
2
1
Ba
Cl
X
Y
1
1
1
1

19. Balancing Chemical Equations
BaCl2 + X2Y  BaY + 2XCl
Ba
Cl
X
Y
1
2
2
1
Ba
Cl
X
Y
1
2
2
1
BALANCED!!!
...but not done yet

20. Balancing Chemical Equations
Ba
Cl
NH4
CO3
1
2
2
1
Ba
Cl
NH4
CO3
1
2
2
1
BaCl2 + (NH4)2CO3  BaCO3 + 2NH4Cl
DON’T KEEP X’s and Y’s in your answer. Replace
them with the polyatomic ions. CORRECT!

21. Balancing Chemical Equations
zinc sulfide + oxygen gas  zinc oxide + sulfur dioxide
WORD EQUATION
Convert this to a chemical equation (also known as a “skeleton
equation”).
This is when you use your naming/formula-writing rules!!!
ZnS + O2  ZnO + SO2
CHEMICAL EQUATION

22. Balancing Chemical Equations
ZnS + O2  ZnO + SO2
Zn
S
O
1
1
2
Zn
S
O
1
1
3
Make this number even
by multiplying the
compound that’s causing
the oddness by 2

23. Balancing Chemical Equations
ZnS + O2  2ZnO + SO2
Zn
S
O
1
1
2
Zn
S
O
2
1
4

24. Balancing Chemical Equations
2ZnS + O2  2ZnO + SO2
Zn
S
O
2
2
2
Zn
S
O
2
1
4

25. Balancing Chemical Equations
2ZnS + O2  2ZnO + 2SO2
Zn
S
O
2
2
2
Zn
S
O
2
2
6

26. Balancing Chemical Equations
2ZnS + 3O2  2ZnO + 2SO2
Zn
S
O
2
2
6
Zn
S
O
2
2
6
BALANCED!!!