Rip The Can: Difference between revisions
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# 5 minutes before the demonstration, pour 100mL of the copper (II) chloride solution into one of the cans, and set it in the large tub. | # 5 minutes before the demonstration, pour 100mL of the copper (II) chloride solution into one of the cans, and set it in the large tub. | ||
# When starting the demonstration, tell the audience that you can tear a soda can in half using you "magic gloves", indicating the thick waterproof gloves you are wearing. Show that the soda cans don't have any holes, and demonstrate by pouring some of the copper (II) chloride solution into one in front of the audience. Swirl the can and point out that it isn't leaking, then set it in the large tub. | # When starting the demonstration, tell the audience that you can tear a soda can in half using you "magic gloves", indicating the thick waterproof gloves you are wearing. Show that the soda cans don't have any holes, and demonstrate by pouring some of the copper (II) chloride solution into one in front of the audience. Swirl the can and point out that it isn't leaking, then set it in the large tub. | ||
# Pick up the sodacan that has been sitting for 5 minutes. If you have a third can, you can set it in the bowl and pour it into the new sodacan. Otherwise, pour out the contents into the bowl, and then hold the can sideways, with the top and bottom each in a hand. | # Pick up the sodacan that has been sitting for 5 minutes. If you have a third can, you can set it in the bowl and pour it into the new sodacan. Otherwise, pour out the contents into the bowl, and then hold the can sideways, with the top and bottom each in a hand. Grip the can and twist it while pulling, and it will rip apart! | ||
# Ask the audience if they think this has to do with your gloves or something else. Explain the demonstration while performing it with the second soda can. | # Ask the audience if they think this has to do with your gloves or something else. Explain the demonstration while performing it with the second soda can. | ||
Latest revision as of 15:02, 22 August 2016
| Chemistry: | Single Replacement Reactions |
| Grade Range: | Elementary School, Middle School, High School |
| Format: | Stage |
This demonstration needs some preparation time, so plan accordingly in order to present it successfully. Be sure to bring plenty of backup soda cans, because students will love to see it over and over again!
Materials
- Soda Cans
- Large Tub
- Screwdriver
- Copper (II) Chloride Solution
Safety Precautions
Please read the Liquid Chemical section of the Demonstration Safety page before performing this demonstration.
This demonstration requires: Safety glasses, thick waterproof gloves, small blast shield
The waste solution from this demonstration cannot be poured down a drain. Bring the waste solution back from the location and pour it into a waste container.
Demonstration
- Preparation
- Prepare the copper (II) chloride solution: Dissolve 8g of the salt in 400mL of water. Once fully dissolved, store in a 500mL bottle with preparation date and initials.
- Prepare the soda cans: Use the screwdriver to scrape the inside of the soda can and remove part of the inner plastic lining. scratch several circles into the walls of the can, being sure not to puncture the can in the process.
- Presentation
- 5 minutes before the demonstration, pour 100mL of the copper (II) chloride solution into one of the cans, and set it in the large tub.
- When starting the demonstration, tell the audience that you can tear a soda can in half using you "magic gloves", indicating the thick waterproof gloves you are wearing. Show that the soda cans don't have any holes, and demonstrate by pouring some of the copper (II) chloride solution into one in front of the audience. Swirl the can and point out that it isn't leaking, then set it in the large tub.
- Pick up the sodacan that has been sitting for 5 minutes. If you have a third can, you can set it in the bowl and pour it into the new sodacan. Otherwise, pour out the contents into the bowl, and then hold the can sideways, with the top and bottom each in a hand. Grip the can and twist it while pulling, and it will rip apart!
- Ask the audience if they think this has to do with your gloves or something else. Explain the demonstration while performing it with the second soda can.
Why This Works
A Single Replacement Reaction is when a reaction has a single element replace another element in a compound. This type of reaction is quite common, and visually it is easy to see what happens:
| Reactants | Products | |
| A + B-C | → | A-C + B |
For this demonstration, the copper (II) chloride reacts with the aluminum wall of the can. Since aluminum is more reactive than copper, it will replace the copper in solution, and cause the copper to precipitate onto the can wall:
| Reactants | Products | |
| 2 Al(s) + 3 CuCl2 (aq) | → | 2 AlCl3 (aq) + 3 Cu(s) |
Since the aluminum wall is dissolving, and the deposited copper isn't filling the holes, the can walls become weak quickly. After a period of just a few minutes, the can is weak enough that it can be pulled apart!
Additional Information
- Knowing about the reactivity of materials is important when making packaging. The inside of a soda can has a thin plastic layer to prevent the aluminum from reacting with the acid in the soda!
- If students ask about double replacement reactions, you can tell them about a common one: baking soda and vinegar! Since it is two compounds that exchange elements, it is a double replacement reaction with products that instantly decompose into water and CO2 bubbles!
- This demonstration is a part of the Chemistry Show.