Question: how many grams are needed to obtain 1.5 moles of magnesium oxide?
Answer: Therefore from Avogadro's Law, 2 moles of Mg combine with 1 mole of Oxygen to form 2 moles of MgO. Here, 1.5 moles of Oxygen take part in the reaction, which reacts with 1.5 X 2 = 3 moles of Magnesium. = 24.305 X 3 = 72.915 grams which is the required answer.