An hydrocarbon is #92.3%# with respect to carbon. What is its empirical formula? And if the mass of the molecule is #26*g*mol^-1#, what is its molecular formula?
It is likely acetylene.
We assume 100 g of compound, and divide thru by the atomic masses:
So, clearly, the empirical formula is
But we have been given a molecular mass, and it is a fact that the molecular formula is always a multiple of the empirical formula: