Today I took a familiar but intriguing chemical reaction and brought it into a popping experience. I took three one-quart plastic bags and in each of them I added 1 tablespoon of baking soda.
I then filled three snack sized bags with different quantities of vinegar. Using a drinking glass to help me hold the bags open, I filled one bag with a 1/2 cup (120mL) of vinegar, another with a 1/3 cup (80mL), and the last one with 1/4 cup (60mL).
Then I sealed the snack bags containing the vinegar and placed them inside the quart bags with the baking soda. I then squeezed all the air I could out of the bag.
Once every bag was set for a scientific reaction, I grabbed a cookie sheet and headed outside.
Enjoying the day of warmth, I set the tray on a table. Not knowing which bag to do first, I decided on the bag with a 1/2 cup of vinegar. With a punch, I broke the inner bag releasing the vinegar. I shook the bag to help the reactants mix.
As the reaction produced carbon dioxide, it filled up the bag, pushing against the plastic as hard as it could.
It kept growing…..
..and growing…
..and growing…
..and growing too big for my taste…
..and yet it still grew! This is how big it got.
Then the overstuffed pillow finally popped.
The next two were not as exciting, but I learned a lot.
The 1/3 cup vinegar bag was difficult to break.
But after squeezing it into submission, the vinegar mixed with the baking soda. This is how big the bag got.
It obviously did not get as big as the 1/2 cup bag. Thus, it did not pop.
This is the 1/4 cup reaction. the bag didn’t even blow up very big.
This is an experiment on limiting reactants. In this situation, the limiting reactant is the vinegar. Because it is the only variable changing, everything else is relatively the same. In the 1/2 cup vinegar test, the baking soda had all the vinegar it wanted to make a lot of CO2 . However the 1/3 and the 1/4 cup was not a lot of vinegar to let the baking soda be fully used up. Thus as the amount of vinegar went down, so did the amount of CO2 . There just wasn’t enough vinegar to satisfy the needs of the baking soda. You didn’t know that, in some situations, baking soda can be picky!
