The document provides step-by-step instructions for balancing chemical equations. It demonstrates how to balance equations with monatomic and polyatomic ions, including making coefficients even numbers when needed. Examples show balancing equations such as H2O2 → H2O + O2, CaSO4 + KOH → Ca(OH)2 + K2SO4, and ZnS + O2 → ZnO + SO2. Key steps include writing element symbols, choosing coefficients, and balancing the numbers of each element on both sides of the equation.

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!!!