As we know 1 mole of O₂ gas contain 6.022 × 10²³ Molecules.
And,
1 mole of O₂ contains 6.022 × 10²³ × 2 Oxygen atoms.
Also,
1 mole of H₂O contains 6.022 × 10²³ Oxygen atoms.
So,
2 moles of H₂O will have 6.022 × 10²³ × 2 Oxygen atoms.
Therefore, we need to take 2 moles of water as 2 moles of water contains exactly the same number of oxygen atoms as that 1 mole of O₂ gas contains.
So,
1 Mole of H₂O = 18 g
Then,
2 Moles of H₂O = X g
Solving for X,
X = (2 mol × 18 g) ÷ 1 mol
X = 36 g H₂O
Result:
36 g of H₂O have the same number of Oxygen Atoms as contained by 1 Mole of O₂ gas.