How many iron atoms are in 5.4 mol of Fe203?

6.5*10²⁴ atoms Fe

Explanation:

First find moles of iron:

5.4 mol Fe₂O₃ * (2 mol Fe / mol Fe₂O₃) = 10.8 mol Fe

Now calculate atoms of iron:

10.8 mol Fe * (6.02*10²³ atoms Fe / mol Fe) = 6.5*10²⁴ atoms Fe