Answer:
13.5
Explanation:
Molar mass of Fe2O3 = 2*56 + 16*3 = 112 + 48 =160 approximate value
Number of moles of Fe2O3 = mass/molar mass = 40/160 = 0.25 mol
The reaction is balanced. Fine
1 mol of Fe2O3--------> 2 mol of Al
0.25 mol--------> 0.25*2 = 0.5 mol of Al
Mass of Al required = Number of moles * Molar mass
= 0.5 * 27 = 13.5 g