1. utilizes electrical energy to create chemical energy
Electrolytic Cells
utilizes electrical energy
to create chemical energy

2. Electrolytic Cells
electricity used to force non-spontaneous reactions to occur = endothermic
electrolytic cells identified by presence of battery or power supply

3. Galvanic Cell
Chemical
Potential
Energy
Electrical
Potential
Energy
Electrolytic Cell

4. Electrolytic Decomposition of H2O
H2 produced at one electrode, O2 at other
2H2O + energy 2H2 + O2
Can you tell from the picture which electrode is producing H2? Which is producing O2?

5. Electrolytic cell works as the reverse of a galvanic cell
this time:
Zn is cathode; where reduced takes place
&
Cu is anode; where oxidation takes place

6. Two kinds of electrolytic cells
Fused Salt Cells – used to purify metals
(Fused means melted!)
Electroplating Cells – designed to cover a surface with metal so will have specific properties

8. Electroplating
Move desired coating from anode onto object to be plated
Solution contains ions of element to be plated

9. Electroplating: Cu onto Al
Al above Cu in Table J
reaction will not happen spontaneously so…
use external energy source (power supply or battery) to force reaction to occur

10. An Ox ate a Red Cat anode: electrode at which oxidation occurs
cathode: electrode at which reduction occurs
Electrode polarity opposite than galvanic cell!
anode is positive
cathode is negative

11. A POX on Electrolytic Cells
Anode – Positive – Oxidation
electrolytic cell: polarity determined by outside power supply
anode attached to (+) terminal
cathode attached to (-) terminal

12. (+) (-) (+) (-) Anode = Oxidation Cu  Cu+2 + 2e- Battery
Cathode (Obj being Plated)
= Reduction
Cu e-  Cu
(-)
Cu+2 and SO4-2
Note: just moving Cu around

14. Plating cathode = object to be plated
anode - made of metal want to plate on object
solution: contains ions of plating metal
Plating

15. purify metals from their ores Fused Salt Cells: used to
Ox: 2Cl-1  Cl2 + 2e-
Red: Na+1 + 1e-  Na

16. Why does NaCl have to be molten?
Which electrode will Na+1 ions be attracted to?
Which electrode will Cl-1 ions be attracted to?