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I want to thank you. Your site has really helped me develop interesting and appropriate demonstrations and observation activities for my class. Recently, I consulted your data base to discover that the chemical compositions of vinegar and baking soda were H2O+C2H4O2 and NaHCO3. I was also able to determine that the chemical reaction from the mixing of the two results in the release of CO2 gas. I have not been able to find, however, what the chemical composition of the remaining liquid is. I understand (I think) that combinations of acids and bases create salts. Is that true in this situation? Is the liquid some form of salt? Can you help me? Thanx!!!
Micheltorena Street School, Los Angeles, CA
Well, the first thing to notice is that vinegar is mostly water, with a little acetic acid (HC2H3O2). The Sodium
ion in the baking soda is exchanged for the Hydrogen ion in the
vinegar, giving NaC2H3O2 and H2CO3. The name for the former compount is
Sodium Acetate (the "salt"), and H2C03 is Carbonic Acid. It's really
also just dissolved C02 and a water molecule. In fact, carbonated
beverages really have carbonic acid dissolved in the water.
To be more precise, most of the ions of these compounds are
dissociated in the water anyway, until the ions combine to form CO2 gas
and H2O. The dissolved sodium acetate will be dissociated into ions,
Na+ and a negative acetate.
(republished on 07/13/06)
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