3.297 g of a substance (containing only C, H, and O) is burned in a combustion analysis apparatus.

Question

The mass of CO2 produced is 3.626 g, and the mass of H2O produced is 9.897×10-1 g.
What is the empirical formula of the compound?

Answer 1

g CO2 = 3.626
g H2O = 0.9897
Plan.
1. Convert g CO2 to g C.
2. Convert g H2O to g H.
3. Find g O in the C,H,O compound from
3.297g total - g C - g H = g O.

mols CO2 = g/molar mass = 0.0842 and that x 12 = 0.9889 g C
g H = 0.9897*2/18 = 0.1099
g O = 2.198

Convert g each to mols.
0.9889/12 = ?
0.1099/1 = ?
2.198/16 = ?

Now find the ratio in whole numbers with the smallest number being 1.00. The easy way to do that is to divide the smallest number by itself and divide the other numbers by the same small number. You will get fractions and not whole numbers. To obtain whole numbers, multiply everything by 2, then 3, then 4, etc until you obtain a set of almost whole numbers, then round to the nearest whole number.
Post your work if you get stuck.