Making a Copper-Zinc Battery, Demo #29

This demonstration illustrates what is necessary to make a simple working battery.  One needs only some pieces of copper and zinc  metal, water solutions of copper and zinc sulfates, and a projection voltmeter.

Mystery of the 9-Volt Battery, Demo #30

After a discussion of standard reduction potentials, most students conclude that the battery having the highest possible voltage must be made from lithium and fluorine.  This will give a standard voltage of a little over 5V.  How then is it possible for stores to sell 9V transistor batteries?  This demonstration solves the mystery by showing what is inside such a cell.

Copper (II) Concentration Cell, Demo #35

One can set up a Galvanic cell that plates out copper metal from a concentrated copper (II) solution and dissolves copper metal from a electrode into a dilute copper (II) solution.  The cell potential depends on the concentrations of copper (II) and can be compared to the voltage predicted by the Nerst equation.