1. Electrochemical Cells
Taking redox to the next level!

2. Realization!
This is where the movement of electrons hits the road: the release or absorption of energy (electricity) determines which reactions occur.
If there is a positive reduction cell potential, then the reaction is spontaneous. Obviously, this means that if the reduction cell potential is negative, the reaction will not occur unless it is driven, usually by an outside application of energy/electricity.

3. History lesson
1800: Alessandro Volta: first electrochemical cell to generate DC current.
Salt bridge: see section 21.1, read about salt bridges and batteries.

4. Practical Cells
Voltaic cells: generate flow of electric current via a spontaneous redox reaction
Electrolytic cells: require an outside source of current for the reaction to occur
Examples:
Electroysis of water, brine,
Electroplating of metals: Ag, Cu, Ni, Cr
Electrorefining: Ag, Pb, Cu
Electrowinning: Al