When 24.2 mole of aluminum reacts with excess oxygen according to the reaction, how many moles of aluminum oxide can be produced 4Al+3O2 ——->2Al2O3

Question

When 24.2 mole of aluminum reacts with excess oxygen according to the reaction, how many moles of aluminum oxide can be produced 4Al+3O2 ——->2Al2O3

Answer 1

4Al(s) + 3O₂(g) ==> 2Al₂O₃(s) ... balanced equation

24.2.........xs................?............

Looking at the balanced equation, we see the mol ratio of Al to Al₂O₃ is 4 : 2 or 2 : 1 and so the moles of Al₂O₃ formed will be 1/2 the moles of Al used, i.e. 1/2 x 24.2 = 12.1 moles.

Doing this by dimensional analysis, which is recommended, looks like this:

24.2 mol Al x 2 mole Al₂O₃ / 4 moles Al = 12.1 moles Al₂O₃