Wonderama Rules: Safety first. Wear safety glasses and alway ask permission and be supervised by an adult when conducting an experiment.
Yes, you CAN try this at home! On this week’s segment of Cool Science with Rachel, we learned how to restrain a gas (with explosive results). No, David, not the Stinky Pig kind of gas… the kind that we breathe out: carbon dioxide! For this and any experiment, be sure to ask an adult’s permission, and carry out the steps in a place that would be okay with a little spillage, like your backyard or even on top of a baking sheet.
- Baking soda (sodium bicarbonate)
- Vinegar (acetic acid)
- 1 gallon zip-top plastic bag
- Bag clip
- Measuring cups
- Put 2 cups of vinegar in the plastic bag.
- Twist the bag above the vinegar tightly and secure with the bag clip.
- In the open section of the bag above the clip, add ½ cup of baking soda.
- Seal the bag with and make sure that the zipper is closed all the way across.
- Remove the clip from the bag, shake so that the baking soda falls down into the vinegar, and stand back!
This is the same kind of chemical reaction that you would use if you were making a volcano for a science fair, but in this case we are restraining the gas inside the plastic bag. Because gas has a tendency to expand infinitely, it pushes against the walls of the bag until the strength of the plastic gives out. The reaction takes place in 2 steps:
- Acetic acid reacts with sodium bicarbonate to form sodium acetate and carbonic acid.
NaHCO3 + HC2H3O2 → NaC2H3O2 + H2CO3
Sodium bicarbonate + Acetic acid → Sodium acetate + Carbonic acid
- Carbonic acid is the same kind that makes your soda fizzy! It’s unstable, so it undergoes a decomposition reaction to produce water and carbon dioxide gas.
H2CO3 → H2O + CO2
Carbonic acid → Water + Carbon dioxide
The full reaction (combining the 2 steps) looks like this:
NaHCO3 + HC2H3O2→ H2O + CO2
For more information on the reaction, click on the following citation: