Answer
1 mole = 31.998 grams
Procedure
To determine the weight of a molecule you will need to first retrieve the molecular weight of the elements that compose the molecule. In this case, the only element is Oxygen.
By looking at the periodic table oxygen has a molecular weight of 15.999 g/mole
Then you will need to multiply that weight for the number of atoms in the molecules in this case O₂ has 2 oxygen atoms.
Therefore
15.999 (2) =31.998 g/mol
