I hate to tell you this but carbonated water is NOT CH2O. Carbonated water means that you have dissolved carbon dioxide in the water.... what happens to carbonated water or pop when it is left out is that the CO2 comes out of solution making it flat it does not change the chemical structure of water. I don't know everything there is to know about growing but I do have a B.S. in Biochemistry and work as a Chem. Eng. so I have a pretty good grasp on the chemistry end of it.... and yes plants do absorb CO2 through cells in their leaves so it would be a good educated guess that they could absorb the liquid CO2 from the carbonated water.