Move Copper Atoms from a Penny to a Nickel

Objective:  Use electricity to move copper atoms from a penny to a nickel. Transferring metal atoms with electricity is called electroplating.

Materials

9V battery
Clear bowl
1 penny
1 nickel
Rubber gloves
Goggles
¼ cup copper sulfate (Zep Root Kill)
2 alligator clips with a few inches of lead wire

ProcedureDownload the Word document.

  1. Fill the bowl with water.
  2. Clip one alligator lead to the positive terminal on the battery, and clip the other lead to the negative terminal, so that you have two wires coming off the battery. Do not let the leads touch or else electricity will run through the wires too quickly and use up your battery. It will get hot if this happens.
  3. Clip the penny to the lead on the positive terminal, and clip the nickel to the lead on the negative terminal. (You can remember which one by their first letters: penny-positive, nickel-negative.) Don't let the coins touch or else the warning in step 3 will happen.
  4. Dip both coins into the bowl of water ten times without touching each other. What happens to the coins?
  5. Electricity does not travel through pure water. We need to add an electrolyte to carry the charge. Many substances behave like an electrolyte in water, such as salt, vinegar, baking soda, and copper sulfate. We will use copper sulfate because it already has copper in it, which speeds up the process. Protect yourself from the copper sulfate with gloves and goggles.
  6. Dissolve as much copper sulfate into the water as you can. Warming the water helps. It's okay if some extra copper sulfate sits on the bottom of the bowl.
  7. Dip both coins into the bowl of water ten times without touching each other. What happens to the coins?

Questions

  1. If there is copper already in the water, where do you think the nickel is getting copper atoms from?
  2. If the nickel is getting copper atoms out of the water, where are the copper atoms from the penny going?

Conserve
Copper sulfate is a common chemical for chemistry labs. Keep it for future labs, such as:

  1. Flame colors – the copper will cause a flame to turn green. Dip pine cones in a solution of copper sulfate and let them dry, then make your next camp fire look like the Northern Lights. Or coat a few grains with rubbing alcohol in a glass dish and light it on fire. Research electron configurations and electromagnetic radiation.
  2. Insert a piece of zinc (nail or washer) into copper-sulfate water. The zinc will take the copper's place with the sulfate, forcing the copper to clump with itself into little granules that fall to the bottom. Research single-displacement reactions.

Clean Up

  1. Copper sulfate is poisonous for people, and corrosive for metals. Flush your solution down the toilet so it gets sufficiently diluted.
  2. Wash your materials, hands, and working area well with soapy water.

Experiment More

  1. Copper sulfate is a shortcut to getting copper atoms to the nickel. Even though the nickel is getting copper atoms out of the copper-sulfate water, the sulfate just turns around and steals copper atoms from the penny to replace those it lost. Try this experiment with an electrolyte that does not contain copper and see how long it takes for the atoms to travel all the way from the penny.
  2. Try this experiment with other metals, and try reversing the electrodes.