Answer:
We can say, there are 4 mol of oxygen with (4 . NA) = 2.40ₓ10²⁴ atoms
Or just, 4 atoms oxygen.
Explanation:
CH₄ + 2O₂ → CO₂ + 2H₂O
1 mol of methane reacts with 2 mol of oxygen to produce 1 mol of carbon dioxide and 2 mol of water.
We count in 1 mol of CO₂, we have 2 mol of oxygen
In 2 mol of water, we have 2 mol of oxygen.
We can say, there are 4 mol of oxygen with (4 . NA) = 2.40ₓ10²⁴ atoms
Or just, 4 atoms oxygen.