Download Intro to Balancing Equations

Name ______________________________ Date ______________________ Section ____________ Introduction to Balancing Equations
The Law of Conservations of Mass tells us that the total amount of matter is neither created
nor destroyed during any physical or chemical change. Therefore, the mass stays the
same before and after a chemical reaction.
Chemical equations demonstrate this principle because they are always
balanced. The total mass of the reactants must equal the total mass of the
products. You can check to see if an equation is balanced by counting up the
number of atoms- it has to be the same on each side of the equation.
To balance an equation, you can adjust the coefficients until there are the same
number of each type of atom on both sides. You are never allowed to change the
smaller numbers that make up the chemical formulas.
is bala
See! This
nced!
N2
+
3 F2

2 NF3
6
ogens and
and 2 nitr this side!
n
fluorines o
s and 6
2 nitrogen
n this side
fluorines o
Practice
Balance each equation using the law of conservation of mass. There is a chart above each problem
to help you. Use the chart to make sure that you have the same number of atoms on each side.
the
First- Count up
s you
number of atom
e. Write
currently hav
the
that number in
sides of
chart for both
the equation.
Second- If the
numbers don’t m
atch,
try adjusting the
coefficients one
at at
time. Make sure
to
change the num
ber in
the chart.
ou can’t
Remember- y
mulas!
change the for
1.
Reactants
Products
H
H
O
O
____ H2
2.
+
____ O2

Reactants
Products
P
P
O
O
____ P4
+
____ H2O
____ O2
©2015 Adventures in Science

____ P2O3
You should
do this in
pencil!
Reactants
Products
N
H
____ N2
5.
+
Reactants
Products
N
K
K
H
Cl
Cl
____ H2 
4.
____ NH3
____ K
6.
+
Reactants
____ Cl2 
Reactants
Products
C
C
Ga
Ga
F
F
F
F
Br
Br
Cs
Cs
____ KCl
Products
___ CF4 + ___ Br2  ___ CBr4 + ___ F2
___GaF3 + ___ Cs  ___ CsF + ___ Ga
7.
8.
Reactants
Products
Products
Ag
Ag
Ba
Ba
N
N
S
S
O
O
Pt
Pt
Cu
Cu
F
F
___ AgNO3 + ___ Cu  ___ Cu(NO3)2 + ___ Ag
9.
Reactants
___ BaS + ___ PtF2  ___ BaF2 + ___ PtS
Reactants
Products
Na
Na
Mg
Mg
P
P
F
F
O
O
Li
Li
K
K
C
C
H
H
O
O
___ Na3PO4 + ___ KOH  ___ NaOH + ___ K3PO4
10.
Reactants
Products
___ MgF2 + ___ Li2CO3  ___ MgCO3 + ___ LiF
©2015 Adventures in Science
3.
Answers
Name ______________________________ Date ______________________ Section ____________ Introduction to Balancing Equations
The Law of Conservations of Mass tells us that the total amount of matter is neither created
nor destroyed during any physical or chemical change. Therefore, the mass stays the
same before and after a chemical reaction.
Chemical equations demonstrate this principle because they are always
balanced. The total mass of the reactants must equal the total mass of the
products. You can check to see if an equation is balanced by counting up the
number of atoms- it has to be the same on each side of the equation.
To balance an equation, you can adjust the coefficients until there are the same
number of each type of atom on both sides. You are never allowed to change the
smaller numbers that make up the chemical formulas.
is bala
See! This
nced!
N2
+
3 F2

2 NF3
6
ogens and
and 2 nitr this side!
n
fluorines o
s and 6
2 nitrogen
n this side
fluorines o
Practice
Balance each equation using the law of conservation of mass. There is a chart above each problem
to help you. Use the chart to make sure that you have the same number of atoms on each side.
the
First- Count up
s you
number of atom
e. Write
currently hav
the
that number in
sides of
chart for both
the equation.
Second- If the
numbers don’t m
atch,
try adjusting the
coefficients one
at at
time. Make sure
to
change the num
ber in
the chart.
ou can’t
Remember- y
mulas!
change the for
1.
Reactants
Products
H
4
H
4
O
2
O
2
2 H2
____
2.
+
____ O2

Reactants
2 H 2O
____
Products
P
4
P
4
O
6
O
6
____ P4
+
3 O
____
2
©2015 Adventures in Science

2 PO
____
2 3
You should
do this in
pencil!
Reactants
4.
Reactants
Products
N
2
N
2
K
2
K
2
H
6
H
6
Cl
2
Cl
2
____ N2
5.
Products
3 H 
____
2
+
Reactants
2 NH
____
3
Products
2 K
____
6.
____ Cl2 
+
Reactants
2 KCl
____
Products
C
1
C
1
Ga
1
Ga
1
F
4
F
4
F
3
F
3
Br
4
Br
4
Cs
3
Cs
3
2 Br  ___ CBr + ___
2 F
___ CF4 + ___
2
4
2
3 Cs  ___
3 CsF + ___ Ga
___GaF3 + ___
7.
8.
Reactants
Products
Reactants
Products
Ag
2
Ag
2
Ba
1
Ba
1
N
2
N
2
S
1
S
1
O
6
O
6
Pt
1
Pt
1
Cu
1
Cu
1
F
2
F
2
2 AgNO3 + ___ Cu  ___ Cu(NO3)2 + ___
2 Ag
___
___ BaS + ___ PtF2  ___ BaF2 + ___ PtS
9.
10.
Reactants
Products
Reactants
Products
Na
3
Na
3
Mg
1
Mg
1
P
1
P
1
F
2
F
2
O
7
O
7
Li
2
Li
2
K
3
K
3
C
1
C
1
H
3
H
3
O
3
O
3
3 KOH  ___
3 NaOH + ___ K3PO4
___ Na3PO4 + ___
2 LiF
___ MgF2 + ___ Li2CO3  ___ MgCO3 + ___
©2015 Adventures in Science
3.