Answer:
0.167 mol Fe
Step-by-step explanation:
4 Fe + 3 O₂ ⇒ 2 Fe₂O₃
Convert moles of oxygen to moles of iron using the mole ratio. You can find the mole ratio using the chemical equation. For every 4 moles of iron, you will need 3 moles of oxygen.
(0.125 mol O₂) (4 mol Fe/3 mol O₂) = 0.167 mol Fe