Can you calculate the empirical and molecular formula of an organic compound given the following data....?

A #2.524*g# mass of an organic substance containing #C, H, O# gave a mass of #3.703*g# with respect to carbon dioxide, and a #1.514*g# mass of water upon combustion. The compound has a molecular mass of #360.3*g*mol^-1#.

1 Answer
Nov 6, 2017

#"Empirical formula"-=CH_2O#

#"Molecular formula"-=C_12H_24O_12#

Explanation:

With respect to the original sample....

#"Moles of carbon dioxide"=(3.703*g)/(44.01*g*mol^-1)=0.08414*mol#.

There were thus #0.08414*molxx12.011*g*mol^-1=1.011*g# with respect to carbon in the original sample....

#"Moles of water"=(1.514*g)/(18.01*g*mol^-1)=0.08406*mol#.

There were thus #2xx0.08406*molxx1.00794*g*mol^-1=0.1695*g# with respect to hydrogen in the original sample....

And the balance of the mass....#2.524*g-1.011*g-0.1695*g=1.3435*g# was due to oxygen, i.e. a molar quantity of #(1.3435*g)/(16.00*g*mol^-1)=0.08397*mol#.

And thus in the ORIGINAL sample there were 1:2:1 molar quantites of carbon, hydrogen, and oxygen, i.e. an empirical formula of #CH_2O#....and given the starting condition, a molecular formula of #C_12H_24O_12#...