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

1 Answer
Apr 26, 2016

#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.