Answer: 1.9 moles SO₂
Explanation:
1) The chemical formula SO₂ shows that for every mol of SO₂ there are 1 mol of S and two moles of O.
2) Then you can state the proportion between the number of moles of SO₂ and O to find how many moles of SO₂:contains 3.8 moles of O.
1 mol SO₂ x
-------------------- = --------------------------
2 moles O 3.8 moles O
3) Now, you can clear x:
x = 3.8 moles O × 1 mol SO₂ / 2 moles O.
x = 1.9 moles SO₂.
