Empirical Formula Example 2
Mg (solid – silvery white) + O2 (gas)  →  MgxOy (solid – white)
heat
(0.353g)
limiting reagent
(0.585g)
resulting mass
Atmospheric oxygen is in excess
A student burns 0.353 g of magnesium ribbon in an open crucible.  A white powder forms and is found to weigh 0.585 g.  What is the empirical formula?
How do we determine the empirical formula?