well to day i went to the library with _____ and we borrowed a lot of books...economists racism a couple of romance novels....

this is an experiment that i did....

1) some old coins
2)baking soda(sodium bicarbonate)
3)water

mix them up
leave them for a few days and the solution turns blue...(AMAZING)

deduction: copper 2+ ions.....something in the baking soda is more reactive than the copper coins that it displace it...i dunno my chem is a little rusty....but isn't the coins alloy or something....maybe nickel.....

so my final hunch is that NaHCO3 when reacts with water leaving Na+ and HCO3-....
Also, a different amount of water sticks to the bicarbonate ion. so the Na+ will displace the copper atoms(or some other metel atoms that gives blue ions) from the coins leaving those blue ions............done..