Oxidation and Reduction

Edwina Nelson                    William W. Carter
                                 5740 South Michigan Ave.
                                 Chicago, Il 60637
                                 312-947-7160

Objectives:

Grade Level 8th
To construct an electroplating device.
To describe chemical changes that involve the transfer of electrons.
To describe the procedures used and the reactions occurring during the 
   electroplating of a metal.

Materials Needed:

300mL beaker                                6 volt battery
Alligator Clips                             Copper sulfate solution (CuSO4)
Copper Strip                                Spoon

Recommended Strategy:

     Draw large cartoon on board.  Student bringing a RED-OX to class-explaining 
very defensively that; "The book said the class would be studying RED-OX 
behavior."  Say, "Class-How's this REED OX-He eats REEDS in the forest and takes 
naps in the afternoon."  What do we mean by- ReDox?  Today we will participate in 
an activity, "YOU CAN'T LOSE FOR WINNING", (printed on board).  Explain to 
students that Electroplating (today's activity) is a form of oxidation-reduction.  
Say to students, "We will now collect materials placed on the Lab table, take one 
of each.  Working in groups, students set up electroplating apparatus.  Directions 
are given on lab sheets; Pour 150mL of the Copper Sulfate solution in a 300 mL 
beaker.  Place the spoon and the copper strip in the solution.  CAUTION: THE SPOON 
AND THE COPPER STRIP SHOULD NOT TOUCH.  Attach one alligator clip to the spoon 
(the metal being reduced).  Attach one alligator clip to the copper strip (the 
metal being oxidized.)  IMPORTANT: Connect the spoon to the negative terminal of 
the battery and the copper strip to the positive terminal.  Wait approximately 5-7 
minutes for a reaction.  The students should observe the color of the solution.  
Red copper color is evident on the spoon.  Disconnect the alligator clips, remove 
the spoon and copper strip from solution, observe end of copper strip that was 
attached to alligator clip and discuss observations.  Discuss the value of 
electroplating.  Concepts students should comprehend are that oxidation is a loss 
of electrons, reduction a gain of electrons.  The battery supplied the extra 
electrons.  The (Cu) ions in the solution combine with the extra electrons on the 
object to be plated.  The copper strip becomes oxidized (loses electrons) and the 
spoon becomes reduced (gains electrons).