4Al + 3O2 → 2Al2O3 a. If you use 2.3 moles of Al, how many moles of Al2O3 can ... How many grams of Al2O3 are produced from the reaction of 5 moles of Al?
So in one hour half the amount remains (that's what half life means). In two hours 1/4 (or half of half) would remain and in three hours 1/8 would remain. So the answer is 1/8
