In an experiment 10.124 g of magnesium is reacted with 4.273 g of oxygen gas according to the equation:

Mg + O2 ==> MgO.

A. What is the limiting reactant?
B. What mass of the other reactant is in exess?
C. What mass of MgO is produced?

You can use the Fe2O3 + CO problem I've just posted for you to do this one. The beauty of these stoichiometry problems is they all fit pretty much into the same mold. Remember the steps and you can work almost any of them. Post your work if you get stuck on this but tell us exactly, and in detail, what you are having trouble with.