Question

A compound has an empirical formula of CHO2 and a molecular mass of 135 g/mole. Determine the molecular formula?

Answer 1

Consider the empirical formula,

`CHO_2 (MW_e = (45g)/"mol")`

of a compound with `MW_m approx (135g)/("mol")`.

At this point, since this compound has an abundance of oxygen atoms, the most efficient method of solution (although not extremely versatile) is merely multiplying the empirical formula's weight by successive integers until we arrive at the molecular weight. It's as easy as,

`1MW_e = 45g`,

`2MW_e = 90g`

`3MW_e = 135g`

I had to! Thus, the molecular formula is,

`C_3H_3O_6`