NEED CHEMISTRY HELP WITH MOLES QUICKEST AND BEST ANSWER 10 PTS?

When looking at the balanced equation it is showing you that it requires 4moles/liter of Al and 3 moles/liter of O2 to form 2 moles/liter of Al2O3. Since the question says that you have 8 moles of Al, you double all the numbers in the equation which gives you 6 moles of O2