# What is the empirical formula of an unknown compound that contains 60.3% of magnesium and 39.7% of oxygen?

Apr 26, 2016

$M g O$, magnesium oxide.

#### Explanation:

For empirical formula problems we assume 100 g of compound, and then divide thru by the ATOMIC weights of each constituent.

There are thus (60.3*g)/(24.305*g*mol^-1 $=$ $2.48 \cdot m o l \cdot M g$, and

(39.7*g)/(15.999*g*mol^-1 $=$ $2.48 \cdot m o l \cdot O$.

There is clearly a $1 : 1$ molar equivalence, and the empirical formula is $M g O$, as we would anticipate.