Yes, so if one mol = 16g, xmol = .09
Demensional analysis:
1mol/16g x .09g/xmol = (1x.09)/(16) = the answer (about .005)
Thats your conversion factor 1mol=16g.
Another way is to find the mols per gram of a substance (for O, its 1mol/16 or .0625mols per gram.) Take that "oxygen constant" you found and multiply it by the grams you have (.0625mols per gram times .09 grams equals .005mols)