For the Following questions, consider the reaction between magnesium and oxygen.
Mg(s)+O2(g) -> MgO(s)
1.How many grams of MgO are produced when 40.0 g of O2 react completely with Mg?
2. How many moles of MgO are produced when 0.20 moles of O2 react completely
3. How many moles of oxygen gas are needed to react with 4.0 moles of Mg?