Balancing Equations

1
Chapter 9

• Balancing Equations
• Part 2

2
Balancing Equation Strategy

• Balance elements that occur in only one compound
  on each side first.
• Balance free elements last.
• Balance unchanged polyatomic ions as groups.
• Fractional coefficients are acceptable but must
  be cleared at the end using multiplication.

3
Balancing Example
Chemical Equation
C6H14O4 O2 ? CO2 H2O
6
6 7
1. Balance C.
2. Balance H.
3. Balance O.
4. Multiply by two
2 C6H14O4 15 O2 ? 12 CO2 14 H2O
and check all elements.
4
Ca3(PO4)2 H2SO4 ? CaSO4 H3PO4

• In this equation, the polyatomic ions do not
  break up.
• Instead of counting individual atoms, polyatomic
  ion groups may be counted.

5
Ca3(PO4)2 H2SO4 ? CaSO4 H3PO4
6
Cu H2SO4 ? CuSO4 H2O SO2

• The sulfate group breaks up. Each atom must be
  counted individually.

7
Cu H2SO4 ? CuSO4 H2O SO2
8
Balancing Equations

• This method of balancing equations is the
  inspection method.
• The method is trial and error.
• You need to Practice.

9
Homework

• Worksheet Balancing Equations Ch. 9