Answer:
1 mole
Explanation:
m(Fe) = 112 g
n(Fe₂O₃) = ?
First you must calculate how many moles of Fe is in 112 g of Fe:
n(Fe) = m(Fe) / Ar(Fe) = 112 g / 55,85 g moles⁻¹ = 2 moles
Now, from reaction you compare moles of Fe and Fe₂O₃ :
2 n(Fe₂O₃) = n(Fe)
n(Fe₂O₃) = n(Fe) / 2 = 1 mole