Steps for balancing
chemical equations
H2+ O2  H20
Make a list of the elements
in the equation.
H
O
1
Tally the number of
atoms of each element for
the left side of the
equation.
2H
2O
3
Check to see if the
number of atoms is equal
for each element.
2H2
2O1
5
Readjust your tally of
atoms and recheck to see
if they are equal.
2
Tally the number of
atoms of each element for
the right side of the
equation.
2H2
2O1
4
If they are not equal,
write a coefficient in
FRONT of the element or
compound that needs
more atoms.
2H2+ O2  2H20
If they are equal your
equation is balanced. If
not add another
coefficient to a different
element or compound to
make them even.
4H4
2O2
6
8
7
Remember to multiply
the coefficient and the
subscript with each other.
Rules to remember!
9
10
Coefficients MUST be
WHOLE numbers!
3CO2
NOT
You can NEVER EVER
add in or change a
subscript.
1.5CO2
2H20
NOT
H 2 O2
12
11
Coefficients are the same in math
class. Distributive property!
3(x-1)= 3x-3
3H20, means that there are 6 atoms of
hydrogen and 3 atoms of oxygen.
Multiply the coefficient and the
subscript!
13
If you see (parenthesis)
Mg(OH)2
DISTRIBUTE the subscript (2) to
all elements within the
parenthesis.
Mg 1 atom
O 2 atoms
H 2 atoms
14
If an element appears
twice on the SAME side of
an equation you will ADD
them together.
3Mg(OH)2
3 Mg atoms
6 O atoms
6 H atoms
CH4 + O2  CO2 + H2O
So there are
1C1
4H2
2O3
15
So to balance that
equation, you still place a
coefficient in front of the
compounds.
These cards
belong to:
_____________________
CH4 + 2O2  CO2 + 2H2O
1C1
4 H 4 (2 +2)
( 2+2) 4 O 4 (2 +2)
16
18
17