If you don’t have equipment lying around for this experiment, wait until you complete Unit 10 (Electricity) and then come back to complete this experiment. It’s definitely worth it!
Electroplating was first figured out by Michael Faraday. The copper dissolves and shoots over to the key and gets stuck as a thin layer onto the metal key. During this process, hydrogen bubbles up and is released as a gas. People use this technique to add material to undersized parts, for place a protective layer of material on objects, to add aesthetic qualities to an object.
Materials:
- one shiny metal key
- 2 alligator clips
- 9V battery clip
- copper sulfate (MSDS)
- one copper strip or shiny copper penny
- one empty pickle jar
- 9V battery
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Download Student Worksheet & Exercises
Place the copper sulfate in your jar and add a thin stream of water as you stir. Add enough water to make a saturated solution (dissolves most of the solids). Connect one alligator wire to the copper strip and the positive (red) wire from the clip lead. Connect the other alligator wire to the key and the negative (black) lead.
Place the copper strip and the key in the solution without touching each other. (If they touch, you’ll short your circuit and blow up your battery.) Let this sit for a few minutes… and notice what happens.
Clean up: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. Rinse three times, wash with soap, rinse three times.
Wipe off the electrodes. The solution and solids at the bottom of your cup cannot go in the trash. The liquid contains copper, a toxic heavy metal that needs proper disposal and safety precautions. Another chemical reaction needs to be performed to remove the heavy metal from the copper sulfate: Add a thumb sized piece of steel wool to the solution. The chemical reaction will pull out the copper out of the solution. The liquid can be washed down the drain. The solids cannot be washed down the drain, but they can be put in the trash. Use a little water to rinse the container free of the solids.
Place all chemicals, cleaned tools, and glassware in their respective storage places.
Dispose of all solid waste in the garbage. Liquids can be washed down the drain with running water. Let the water run awhile to ensure that they have been diluted and sent downstream.
Exercises
- Look at your key. What color is it?
- Where did the copper on your key come from?
- What happened when you added a second battery?
- Which circuit (series or parallel) did the reaction accelerate faster with?
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