Chapter 21.1

 Electrochemistry occurs through the use of spontaneous redox reactions

 For any two metals in an activity series, the more active metal is the more readily oxidized.

 Because metals have different activities of oxidation, we can use this to do things like electroplating… Zinc is more readily oxidized than copper. Causing the copper to plate the zinc kicking off zinc atoms. As the copper replaces the zinc as a solid, the zinc replaces the copper sulfate with zinc sulfate.

 All electrochemical processes involve redox reactions.  An electrochemical process is any conversion between chemical energy and electrical energy.  An electrochemical cell is any device that converts chemical energy into electrical energy or electrical energy into chemical energy.

 This is an electrochemical cell that converts chemical energy to electrical energy.  Named after Italian physicist Alessandro Volta.

 Electrical energy is produced by a spontaneous redox reaction.  Electrons flow and create a voltage.  Can measure using a voltmeter or use to run a small motor or light a light bulb!

 Redox Reaction:  2Ag + + Cu  2Ag + Cu +2  Identify the electrodes (cathode and anode), salt bridge, and electron flow.

 Galvanic Cell = Voltaic Cell  Have you ever heard of galvanized metal? ◦ It is a metal coated with another metal.

 What current technologies use electrochemical processes to produce electrical energy?  1) Dry Cells  2) Lead Storage Batteries  3) Fuel Cells

 A dry cell is a voltaic cell in which the electrolyte is a paste.  Both dry cells and alkaline batteries are single electrochemical cells that produce about 1.5 V.

 A battery is a group of cells connected together. The half-reactions for a lead storage battery are as follows.  A 12-V car battery consists of six voltaic cells connected together. One cell of a 12-V lead storage battery is illustrated here.

 Are voltaic cells that have renewable electrodes.  Electrical energy is continually obtained and can be designed to emit no air pollution and are more cost-effective. The hydrogen- oxygen fuel cell is a clean source of power. Such cells are often used in spacecraft.

 Build a simple voltaic cell with a partner.  Measure the voltage.  Maybe try hooking it to a motor or light bulb??