What mass of oxygen combines with 2.00 moles of magnesium?

To determine the mass of oxygen that combines with 2.00 moles of magnesium, we first need to consider the chemical reaction: 2Mg + O₂ → 2MgO. This indicates that 2 moles of magnesium react with 1 mole of oxygen. Therefore, 2.00 moles of magnesium will react with 1.00 mole of oxygen. The molar mass of oxygen (O₂) is approximately 32.00 g/mol, so the mass of oxygen that combines with 2.00 moles of magnesium is 1.00 mole × 32.00 g/mol = 32.00 grams.