Question

What mass in grams of oxygen combines with 2.00 moles of magnesium in the formula 2Mg O2 produces 2MgO?

Answer 1

First we make a pretty balanced equation\[\Large2Mg _{s}+ O_{{2}{(g)}} \rightarrow2MgO_{s}\]so we can see that the ratio of oxygen to magnesium is one half becuase one mole of oxygen combines with 2 moles of magnesium. Therefore we just convert one mole of oxygen to grams using the molar mass equation\[moles= \frac{grams}{molar\space mass}\]just remember that thare are two oxygens since it's a gas and is a diatomic molecule. So it's molar mass is 32.00grams per mole not 16. Try and solve it and let me know if you have any questions.