Aluminum reacts with oxygen gas to produce aluminum oxide. How many moles of aluminum oxide would you expect to produce if you reacted 14.5 moles of oxygen gas with excess aluminum?

4Al +3O2 --> 2Al2O3

14.5 mol O2 x 4 mol Al / 3 mol O2 = 19.3 moles

3 answers

You have the right idea but the wrong numbers. You have calculated mols Al. You want mols Al2O3; the problem asks for mols Al2O3.
14.5 mol O2 x 2 mol Al2O3 / 3 mol O2 = 9.67 moles.

Correct?
yes