Redox Review

1. KK+ + 1e- Has potassium been oxidized or reduced?

KK+ + 1e- Potassium has been oxidized, it has become more positive from reactant to product and potassium is a solid on the reactant side.

2. Ag+ + 1e-  Ag Has silver been oxidized or reduced?

Ag+ + 1e-  Ag Silver has been reduced, it has gained an electron to neutralize the ion and it is an ion on the reactant side.

3. K + Na+  K+ + Na Identify which element has been oxidized and which element has been reduced.

K + Na+  K+ + Na Potassium has been oxidized (LEO) and sodium has been reduced (GER).

4. K + Na+  K+ + Na Write the half reactions for potassium and sodium.

K + Na+  K+ + Na K  K+ + 1 e- LEO Na+ + 1e-  Na GER

5. Cu + AgCl  Predict the products.

Cu + AgCl  Cu + AgCl  Ag + CuCl2

6. Cu + AgCl  Ag + CuCl2 Write the half reactions for copper and silver, show that chlorine is the spectator ion

Cu + AgCl  Ag + CuCl2 Cu + Ag+ + Cl-  Ag + Cu+2 + Cl- Chlorine hasn’t changed from reactant to product, so it’s the spectator. Chlorine can be removed. Cu  Cu+2 + 2e- Ag+ + 1e-  Ag Electrons must be equal, so…. 2 x [Ag+ + 1e-  Ag] = 2Ag+ + 2e-  2Ag Now copper and silver electrons are equal

7. Cu + AgCl  Ag + CuCl2 Write the net ionic equation for this reaction.

Cu + AgCl  Ag + CuCl2 Cu + 2Ag+  2Ag + Cu+2

8. Mg + Al+3  Mg+2 + Al Create a half reaction for magnesium and one for aluminum, and balance the electrons.

Mg + Al+3  Mg+2 + Al Mg  Mg+2 + 2e- Al+3 + 3e-  Al So the electrons don’t match, so bring each equation up to 6e- by multiplication. 3 x [Mg  Mg+2 + 2e-] = 3Mg  3Mg+2 + 6e- 2 x [Al+3 + 3e-  Al] = 2Al+3 + 6e-  2Al

9. Diagram lithium with sodium, identify anode and cathode Porous cup V

lithium with sodium Porous cup V Li Na Na+ Li+

10. Create half reactions and a net ionic equation for lithium and sodium V Li Na Na+ Li+

Li  Li+ + 1 e- ; Na+ + 1e-  Na Li + Na+  Li+ + Na V Li Na Na+ Li+

11. An Ox sat on a big Red Cat, where does oxidation and reduction take place? Li  Li+ + 1 e- Na+ + 1e-  Na

Li  Li+ + 1 e- Na+ + 1e-  Na Lithium = LEO , oxidation takes place at the anode. Sodium = GER, reduction takes place at the cathode.

12. Assign oxidation numbers PbSO4 H2 H2O NaCl Ag+ SO4-2 Na

Oxidation numbers PbSO4 ; Pb = +2, S = +6, O= -2 x 4 oxygens = -8 H2 = 0 H2O; H = +1, 2 hydrogens = +2; O = -2 NaCl; Na= +1, Cl = -1 Ag+ = +1 SO4-2; S = + 6, O = -2 x 4 oxygens = -8; -2 is the final charge Na = 0

13. Identify this equation as Redox using oxidation numbers Na +AgCl  NaCl + Ag

Oxidation numbers Na +AgCl  NaCl + Ag Na: 0  +1 LEO Ag: +1  0 GER Cl- both sides spectator ion

14. Identify LEO and GER for the following equation Cu + AgBr CuBr2 + Ag

Oxidation Numbers Cu + AgBr  CuBr2 + Ag Cu: 0  +2 LEO Ag :+1  0 GER