Re: What happens to the water molecules when I add Baking Soda and Citric Acid?

Dear Haley,
Your mother is correct when she says the bubbles are carbon dioxide.  The water 
is there only as a solvent, something that converts the two solid reagents into
liquid (solution) so they can react.  Your interest in chemistry is encouraging, 
keep it up!

Milk is a reasonable substitute for water as it is mostly water, but vinegar 
would short-circuit the reaction by making bubbles before the citric acid had a
chance to react.  Lemon juice also contains citric acid so it would add little 
to the situation.

Signed:  Mad Scientist Adjunct