The balanced chemical reaction is expressed as:
2Al(s)+3FeO(s)->3Fe(s)+Al2O3(2)
We are given the amount of FeO to be used in the reaction. This amount will be the starting point for our calculations. It is as follows:
1.2 mol FeO ( 2 mol Al / 3 mol FeO) = 0.8 mol Al needed to react completely