posted by hannah .
How many grams of magnesium oxide are formed when 13.5 L of oxygen gas, measured at STP, completely reacts with magnesium metal according to the following reaction?
i got .496 g
but i know that like way off
n=PV/RT=13.5/22.4*moles of O2, so you will get twice that in MgO, or 13.5/11.2 moles MgO, so what mass of MgO is that number of moles?