Question

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

Answer 1

`MgO`, 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*mol* Mg`, and

`(39.7*g)/(15.999*g*mol^-1` `=` `2.48*mol*O`.

There is clearly a `1:1` molar equivalence, and the empirical formula is `MgO`, as we would anticipate.