What is the empirical formula of a compound that contains 50.0% carbon, 6.7% hydrogen, and 43.3% oxygen by mass?

1 Answer
Apr 25, 2016

C_3H_5O_2

Explanation:

We assume 100 g of unknown compound.

There are thus (50.0*g)/(12.011*g*mol^-1) = 4.163 mol*C.

And (6.7*g)/(1.00794*g*mol^-1) = 6.65 mol*H.

And (43.3*g)/(15.999*g*mol^-1) = 2.71 mol*O.

We divide thru by the lowest molar quantity, that of oxygen to get a formula of C_(1.54)H_(2.45)O_(1), which we double to give a whole number EMPIRICAL formula of C_3H_5O_2.