How many oxygens atoms are in 3CO2 4H2O?

Well, darling, in 3CO2, there are 6 oxygen atoms (3 molecules x 2 oxygen atoms per molecule). In 4H2O, there are 8 oxygen atoms (4 molecules x 2 oxygen atoms per molecule). So, in total, you've got 14 oxygen atoms floating around in that equation. Hope that clears things up for ya!