Diacetyl, a substance contributing to characteristic flavor and aroma of butter, consist of 55.8% C, 7.03% H, and 37.17% O. In the gaseous state at 100 C and 747 torr, a 0.30 gram sample occupies a volume of 111ml. What is the molacular formula of diacetyl?

Answer 1

Say we had 100 grams of this stuff
Then that would be
55.8 g of C
7.03 g of H
37.17 g of O
divide each by atomic weight to get ratio of atoms in molecule
C --> 55.8/12 = 4.65
H --> 7.03/1 = 7.03
O --> 37.17/16 = 2.32
about three H for every O
about two C for every O
so molecule of form:
C2x H3x Ox
and the molecular mass of a mole will be:
16 x + 3x + 24 x = 43 x grams per mole
NOW
find out how many moles you have from
n = P V
/(RT)
we know it weighs .3 grams per n moles
so find out how many grams per mole
then set that equal to 43 x and solve for x