1. Balancing Redox Reactions

2. Steps: 1.Assign oxidation numbers 2.Write half reactions 3.Balance electrons to determine coefficients needed

3. 2HgO  O 2 + 2Hg +2 -2 0 0 Hg +2 + 2e -  Hg 0 Reduction Problem 1: O -2  O 0 + 2e - Oxidation

4. 2KClO 3  2KCl + 3O 2 +1 +5 -2 +1 -1 0 6e- + Cl +5  Cl -1 Reduction Problem 2: 3(O -2  O 0 + 2e - ) Oxidation

5. 2HCl + Zn  ZnCl 2 + H 2 +1 -1 0 +2 -1 0 2e- + 2H +1  H 2 0 Reduction Problem 3: Zn 0  Zn +2 + 2e-Oxidation

6. 2Ag NO 3 + Cu  Cu(NO 3 ) 2 + 2Ag +1 +5 -2 0 +2 +5 -2 0 2e- + 2Ag +1  2Ag 0 Reduction Problem 4: Cu 0  Cu +2 + 2e-Oxidation

7. 4NH 3 + 3O 2  2N 2 + 6H 2 O -3 +1 0 0 +1 -2 12e- + 3O 2 0  6O -2 Reduction Problem 5: 4N -3  2N 2 0 + 12e-Oxidation

8. 3Mg + 2Al(NO 3 ) 3  2Al + 3Mg(NO 3 ) 2 0 +3 +5 -2 0 +2 +5 -2 6e- + 2Al +3  2Al 0 Reduction Problem 6: 3Mg 0  3Mg +2 + 6e-Oxidation

9. 3Ca + 2Al 3+  3Ca 2+ + 2Al 0 +3 +2 0 6e- + 2Al +3  2Al 0 Reduction Problem 6: 3Ca 0  3Ca +2 + 6e-Oxidation

10. 2Fe 3+ + Sn 2+  2Fe 2+ + Sn 4+ 2e- + 2Fe +3  2Fe +2 Reduction Problem 7: Sn +2  Sn +4 + 2e-Oxidation

11. 2HNO 3 + 3MnCl 2 + 6HCl  2NO + 3MnCl 4 + 4H 2 0 +1 +5 -2 +2 -1 +1 -1 +2 -2 +4 -1 +1 -2 6e- + 2N +5  2N +2 Reduction Problem 8: 3Mn +2  3Mn +4 + 6e-Oxidation

12. K 2 (Cr 2 O 7 ) + 14HCl  3Cl 2 + 7H 2 O + 2CrCl 3 + 2KCl +1 +6 -2 +1 -1 0 +1 -2 +3 -1 +1 -1 6e- + Cr 2 +6  2Cr +3 Reduction Problem 9: 6Cl -1  3Cl 2 0 + 6e-Oxidation