A sample of an organic compound with mass of 0.816g was completely burn in oxygen and found to produce 1.556g of co2 and 0.955g of H2O only .calculate the empirical formula if the vapour density is 23?

Answer 1

CxHy + O2 ==> CO2 + H2O (not balanced)
mols CO2 = grams CO2/molar mass = 1.556/44 = about 0.035 = mols C,
mols H2O = 0.955/18 = about 0.053 and mols H = 0.106; i.e., 2*0.053.

mols C = 0.035
mols H = 0.106
Find the ratio of C:H with the smallest number being no less than 1. To do that divide both numbers by the smaller of the two.
0.035/0.035 = 1
0.106/0.035 = 3.03 which rounds to 3.0 so the empirical formula is
C1H3 or CH3. This is the empirical formula. You must have meant to calculate the molecular formula.
vapor density = molar mass compound/molar mass H2 or
23 = molar mass compound/2.016 so molar mass compound = 2.016 x 23 = about 46.3. Thus you know that the molecular formula is a whole multiple of CH3 or 15 so 46.3/15 = about 3.08 which rounds to 3.00 to a whole number so the molecular formula must be (CH3)3 or C3H9.

Answer 2

how did we get 44 to divide 11.556