Balancing Redox Equations

1
Balancing Redox Equations

• Using half reactions

2
Redox

• Oxidation reduction leo says ger
• Lose Electrons Oxidation
• Gain Electrons Reduction (note reduction in
  Charge)

3
Balancing

• 1) Write the half reactions
• 2) Balance each half reaction showing electrons.
• 3) Use water to balance oxygen and hydrogen ions
  to balance water.
• 4) Using least common multiple, balance the
  electrons.

4
Balance

• Sn2 2Fe 3 ? Sn4 2Fe2
• Sn2 ? Sn4 (how many e- where?)
• Sn2 ? Sn4 2e-
• 2Fe 3 ? 2Fe2 (how many e- where?)
• 2Fe 3 2e- ? 2Fe2 (Why 2e-?)
• Note oxidation electrons are treated as products
• That was easy

5
Balance

• Balance this
• MnO4- C2O42- ? Mn2 CO2
• 5e- 8H MnO4- ? Mn2 4H2O
• C2O42- ? 2e- 2CO2