The chemical equation shows the burning of magnesium Mg with oxygen open paren cap o sub 2 close paren to form magnesium oxide MgO 2 Mg plus cap o sub 2 rightarrow 2 MgO The molar mass of cap o sub 2 is 32 point 0 g over mol What mass, in grams, of cap o sub 2 is required to react completely with 4 point 0 0 mol of Mg ?