How many moles of O₂ are there in 1.20 × 10²² oxygen molecules?

Number of molecules of oxygen = 1.20 × 10²² 

One mole of oxygen contains 6.022 × 10²³ molecules.

1.20 × 10²² molecules of oxygen contain = (1.20 × 10²² ) / (6.022 × 10²³ ) = 0.01099 moles.

Therefore, 1.20 × 10²² molecules of oxygen contain 0.01099 moles of oxygen.