The Can Ripper

Science Concept:

When a copper chloride solution is exposed to an aluminum can, the can will corrode and dissolve the aluminum metal to form ions. Copper metal is formed from the copper solution.

Materials:

• 10 g copper chloride crystals (may not use copper sulfate)
• 500 mL distilled water
• triangular file
• 2 aluminum pop cans
• empty 400 mL beaker

Introduction:

Who here thinks that I am stronger than my teacher? Well, Dr. _____ has an empty pop can (the one that is not scratched) and here is my empty can (the one in the solution with the scratch). Here we go!!

Procedure:

• Mix 10 g copper chloride crystals with 500 mL water until dissolved.
• Use file to scratch a line entirely around the inside of a can.
• Pour copper chloride solution into a can past the scratched line.
• Let the can sit for 15 to 20 minutes in the 400 mL beaker.
• When scratched line becomes more pronounced, pour solution into the beaker and rip the can in half.

Explanation:

Aluminum cans have a polymer coating on the inside of the can. When the file is used to scrape away the polymer coating, the aluminum metal is exposed.

The aluminum reacts with the copper chloride solution and an electron exchange takes place. Aluminum gives electrons to the copper ions. This causes the copper ions to turn into copper metal. At the same time aluminum metal turns into aluminum ions.

Al metal + Cu⁺² ions ---> Al ⁺³ ions + Cu metal

The solution ions become a metal (Cu) which are the orange red particles you see at the bottom of the solution. The new aluminum ions have different properties than the aluminum metal. This is why you can easily rip the can in half. The aluminum ions are not in a solid form, but dissolve into the liquid.

 

Safety: Take usual precautions.

Disposal: Save the copper solution for proper waste disposal.

Reference: Flinn Scientific - Chemfax