Baking Soda & Vinegar

[maestro]

i need serious help i am doing a project with this topic:which ratio of baking soda to vinegar produces the most volcanic eruption? I have three days to finish it nd I canot find the answer to it please help

[deleted-71447]

Hi Maestro. What kind of help do you need? Are you running an experiment? Three days should be enough time to run this experiment and to determine which ratio of baking soda to vinegar produces the most "fizz". You could run trials with different ratios of baking soda/ vinegar in a graduated cylinder or measuring cup and then estimate the volume of bubbles produced in each trial.
Good luck,
Chris

[deleted-71712]

Hi Maestro,

Here are a couple of thoughts in addition to Chris's excellent advice:

When you measure the volume of bubbles in the graduated cylinder, some bubbles will have already popped, and some will not have been created yet -- whether or not these amounts are negligible depends on the rates of the reactions. If by "most volcanic eruption", you mean the greatest volume of bubbles at some point in time, this isn't a big deal. But alternately you could define it as the greatest total volume of bubbles produced over time. To measure the total volume of CO2 produced, which is proportional to the amount of acetic acid/sodium bicarbonate reacted, you could use a CO2 trap as discussed here: http://www.sciencebuddies.com/science-f ... =31&t=4546.

You could also try mixing in a small amount of soap with the vinegar before adding baking soda to make the bubbles stick around longer. It would be important to use the same concentration of soap every time. I haven't tried this, but as long as the soap doesn't interfere with the original reactions unexpectedly, you might get more impressive bubbling!

Another thing to think about is that the total amount of reactants consumed (and gas produced) will be predetermined by whichever material you have a smaller amount of. That is, even if you have 1 mole of acetic acid in your solution (distinct from a 1 molar solution -- look up "molarity" if this is unfamiliar), if you only add .2 moles of baking soda, you'll only end up with .2 moles of CO2. And if you added 2 moles of baking soda to the same acetic acid solution, you would get 1 mole of CO2.

The max volume of bubbles could be related to which reactant is in excess (acetic acid is in excess in the first example above, baking soda in the second). If you have baking soda left over at the bottom after the bubbles have stopped, then you know that baking soda was in excess. It may or may not be possible to calculate the actual molarity of the acetic acid solution depending on how it's labeled -- and if you haven't covered solutions in science class, then getting into that much detail would likely be a big bonus rather than expected. Another variable related to the rate of reaction is concentration -- you can experiment with this by diluting the vinegar even if you don't know the absolute concentration.

If you happen to have a video camera, I'd recommend setting it up to film the reaction (at a safe distance away so it stays dry). Not only could this help you read the maximum bubble volume if the volume changes very quickly, but if you participate in a science fair, everyone loves to see demos.

Do you have a hypothesis? If you need help with that, see our project guide: http://www.sciencebuddies.com/science-f ... esis.shtml

Let us know if you have more questions -- even if not, we like to hear how projects turn out!

Best wishes,
Amanda