Oxygen is a diatomic gas,Number of moles of ${{O}_{2}}$ gas
= Atomic weight / Molecular wt = 8/32
=1/4 = 0.25
.’. Energy associated with 1 mole of oxygen = U = 5/2 RT
Internal energy of 8 g of oxygen = 0.25 x 5/2 RT
=0.25 x 5/2 x 8.31 x 273 = 1417. 9 J