How Many grams of magnesium? Help plz

Question

How many grams of magnesium oxide are formed when 14.4 L of oxygen gas, measured at STP, completely reacts with magnesium metal according to this reaction?

2Mg(s)+O2(g)=2MgO(s)

Answer 1

2Mg(s) + O₂(g) ==> 2MgO(s) ... balanced equation

1 mol of any ideal gas at STP = 22.4 L

14.4 L O₂ x 1 mol O₂ / 22.4 L = 0.643 mols O₂

0.643 mols O₂ x 2 mol MgO / mol O₂ = 1.29 mols MgO

1.29 mols MgO x 40.3 g MgO/ mol = 51.8 g MgO