Question

what are the masses of 2moles of atomic oxygen​

Answer 1

Relative atomic mass also equals to a atom's molar mass which is defined as the mass of one mole of that atom. In this,

One mole of oxygen atoms weigh  = 16 g

. Hence two moles weigh  

16  *  2  =  32 g

Answer 2

O2 is a diatomic molecule. The massof an oxygen atom = 16 amu. ∴ Massof O2 molecule = 2 × 16 = 32 amu.