By: Danielle Salvatore

Luigi Galvani discovered when copper and zinc were connected together and then both touched to different parts of a nerve of a frog leg at the same time, they made the leg contract.

This is a common example of a galvanic cell. The cell is split into two parts connected by a salt bridge. Each part is called a half-cell, and consist of one electrode and one electrolyte. This one has two half-cells , copper metal in a solution of copper ions, and zinc metal in a solution of zinc ions.

An arrangement of two half-cells that can produce electricity spontaneously.

://video.google.ca/videosearch?q=danielle+cell&hl=en&emb=0&aq=f#q=galvanic+cell&hl=en&emb=0

Constructed Galvanic Cells

Standard Cell Potentials

Challenge!On your cue card, write out the half-reaction

and E˚. Find your parter AND…• Determine which reaction will be the oxidation and

which will be the reduction in the spontaneous direction.

• Determine which half reaction will occur at the anode and the cathode.

• Together write and balance the net electrochemical reaction they form.

• Determine cell potential.• Arrange yourselves from lowest cell potential to

highest cell potential.

Electrolysis of Aqueous Solutions• Consider who had the electrolysis of water half reactions and

the E˚cell it required.• Whose cell reactions, if they were hooked up to a battery and

run in the NON-SPONTANEOUS direction, would NOT occur because water would react first?

• Calculate all possible cell potentials for your two half-reactions and the two electrolysis half-reactions. Whichever combination is lowest will occur when hooked up to a battery.

• Go stand in one of four groups:• A) Your reaction proceeds as written (no water electrolysis)• B) Your reaction has one water half-reaction producing H2(g)• C) Your reaction has one water half-reaction producing H2(g)• D) Your reaction causes only the electrolysis of water

Homework Extension

• Determine the charge on each electrode.• Write out the short-hand notation for the

Galvanic Cell.• Draw out the Galvanic cell diagram. Show

electron flow, current flow, charge on the electrode and movement of all ions.

• Do the same for the Electrolytic Cell.