1. III.Electrochemical Cells: (ie: Batteries or Galvanic Cells)  Redox reactions that take place in such a way that electrical energy (or voltage) is produced, instead of energy being released as heat (as in the following) eg: Place Zn (s) in Cu(NO 3 ) 2(aq) Zn Cu(NO 3 ) 2 Cu (s) deposits while Zn 2+ dissolves into solution. Cu(NO 3 ) 2(aq) + Zn (s)  Cu (s) + Zn(NO 3 ) 2(aq) Net Ionic: Cu 2+ (aq) + Zn (s)  Cu (s) + Zn 2+ (aq)  In this example energy is released as heat.  We need to modify this system to produce electrical energy rather than heat.

2. eg: An electrochemical cell using Zn and Cu. Cu Cu(NO 3 ) 2 Zn Zn(NO 3 ) 2 Zn (s)  Zn 2+ + 2e - Cu 2+ + 2e -  Cu (s) Salt bridge KNO 3(aq) NO 3 - K+K+ e-e- CATHODECATHODE ANODEANODE Oxidation at AnodeReduction at Cathode

3. Sketch the following electrochemical cells: a)Cs, Mg Practice: b)Zn, Cac)Cu, Mn d)Sn, Cre)Al, Pb  Use nitrates of corresponding metals  Label: anode, cathode, salt bridge, chemicals, and direction of electron and ion flow.  Include the half-reaction for each half cell.  Predict which cell will have the highest voltage.