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
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
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