Answer:
To find the number of moles we must first calculate the molar mass( M) of Fe2O3
Molar mass = mass / number of moles
M(Fe2O3) = (55.8 ×2) + (16×3)
= 111.6 + 48
= 159.6 g/mol
number of moles = mass / molar mass
= 125g/159.6g/mol
= 0.783mol
Hope this helps