Balance Redox Rxns:

1. Balance Redox Rxns: • Fe(OH)3 + [Cr(OH)4]-1 • Fe(OH)2 + CrO4-2 • in base

2. Electrochemistry

3. Metallic Conduction • The flow of electrons through a metal

4. Ionic Conduction • The movement of ions (electrolytes) through a solution • Electrolytic Conduct.

5. Electrode • The surface or point in which oxidation or reduction takes place

6. Anode • The electrode where oxidation takes place • An Ox (-)

7. Cathode • The electrode where reduction takes place • Red Cat (+)

8. Voltaic or Galvanic Cell • Electrochemical Cell in which:

9. a spontaneous oxidation-reduction reaction produces electrical energy

10. Half-Cell • A cell where only oxidation or only reduction takes place

11. An electrochemical cell must have two half-cells connected by a salt bridge

12. A half-cell will not work by itself • Both half-cells are required

13. Salt Bridge • ) Allows electrical contact between the two half-cells

14. ) Prevents mixing of the two half-cell solutions

15. ) Allows ions to flow maintaining electrical neutrality

16. Determining the Redox Rxn & Voltage of an Electrochemical Cell

17. Identify all molecules & ions (reactants) that exist in the electrolytic cell

18. ) Determine all possible half-reactions that could occur in the system

19. ) Look up each half-rxn from the Std. Redox Tables

20. ) Record each half-rxn & its standard voltage

21. ) Save the oxidation half-rxn that has the highest voltage

22. ) Save the reduction half-rxn that has the highest voltage

23. ) Balance the electrons between the two half-rxns

24. ) Add the two half-rxns to obtain the full electrochemical reaction

25. ) Add the voltage of each half-rxn to obtain the std. voltage required

26. Voltaic Cell Problems

27. Determine all when a cell with a Cu electrode in CuCl2(aq) is connected to a cell with a Zn electrode in ZnBr2(aq)

28. Determine all when a cell with a Fe electrode in FeCl3(aq) is connected to a cell with a Mn electrode in MnCl2(aq)

29. Determine all when a cell with a Mg electrode in Mg(NO3)2(aq) is connected to a cell with a Au electrode in Au(NO3)3 (aq)

31. Electrolysis • Using electricity to force a non-spontaneous electrochemical rxn

32. Electrolytic Cell • Chemical cell where electrolysis is being performed

33. How to determine the Redox Rxn & voltage of an Electrolytic Cell

34. Identify all molecules & ions (reactants) that exist in the electrolytic cell

35. ) Determine all possible half-reactions that could occur in the system

36. ) Look up each half-rxn from the Std. Redox Tables

37. ) Record each half-rxn & its standard voltage

38. ) Save the oxidation half-rxn that has the highest voltage

39. ) Save the reduction half-rxn that has the highest voltage

40. ) Balance the electrons between the two half-rxns

41. ) Add the two half-rxns to obtain the full electrochemical reaction

42. ) Add the voltage of each half-rxn to obtain the std. voltage required

43. Determine the rxn that takes place when 1.5 V is passed through two Pt electrodes in a solution containing MgI2(aq) & ZnCl2(aq)

44. 0 • Determine the rxn that takes place when 2.5 V is passed through two Pt electrode in a solution of NaCl(aq)

45. Determine the rxn that takes place when 2.0 V& 9.65 A is passed for 2.5 Hrs through two Pt electrodes in a solution containing MnBr2(aq) & AlF3(aq)

46. Relating Equations • DGo = DHo - TDSo • DGo = -RTlnKeq • DGo = -nFEo

47. Nernst Equation • E = Eo - (RT/nF)lnQ • for non-standard conditions

48. Determine the voltage of a cell with a silver electrode in 1.0 M AgNO3 & an iron electrode in 0.10 M Fe(NO3)2 at 27oC

49. Determine the voltage of a cell with a silver electrode in 1.0 M AgNO3 & a zinc electrode in 0.010 M Zn(NO3)2 at 27oC

50. Determine the voltage of a cell with a copper electrode in 0.10 M CuNO3 & a zinc electrode in 1.0 M Zn(NO3)2 at 27oC