posted by kevin on .
When 1.24g of an organic compound with the formula CxHyOz is burned in excess oxygen, 1.76g of carbon dioxide and 1.08g of water vapor are obtained. What is the empirical formula of the compound?
Determine the moles of CO2 in 1.76grams, that will give you the moles of C in the original compound.
Determine the moles of H2O in 1.08 grams, that will give you the moles of H2, double it, and you have the number of moles in the original compound.
Add the weight of the moles of C in the original compouond to the weight of moles of H in the orig compound, then subtract that weight from 1.24g. The remainder is the weight of O in the compound, now calculate the moles of O in that.
You have the moles of C, H, and O in the original compound.
Take the smaller of those three numbers, and divide into all three. The numbers you get will be the mole ratio.
For instance, assume you had these numbers....C .0024 moles, H .0050 moles, and O .0025 moles.
C is the lower number, dividing, we get