# How do you find the empirical formula of magnesium oxide, when magnesium ribbon is burned in a crucible...and a 0.91*g of material is present?

Apr 2, 2017

There are insufficient data here...........

#### Explanation:

We need (i) the tare mass of the crucible;

(ii) the mass of the crucible and the magnesium metal BEFORE the reaction;

(iii) the mass of the crucible and the resultant magnesium oxide AFTER the rxn.

We interrogate the reaction:

$M g \left(s\right) + \frac{1}{2} {O}_{2} \left(g\right) \rightarrow M g O$

And thus we need the mass of the metal, and the mass of the metal oxide. Do you have $0.91 \cdot g$ of metal or $0.91 \cdot g$ of metal oxide? We need BOTH masses to work out the stoichiometry.