Combustion analysis of 2.400 g of an unknown compound containing carbon, hydrogen, and oxygen produced 4.171 g of CO2 and 2.268 g of H2O. What is the empirical formula of the compound?
We’re being asked to determine the empirical formula of a compound composed of C, H, and O given the combustion analysis.
Recall that in combustion analysis, a compound reacts with excess O2 to form products.
For a compound composed of C, H, and O, the reaction looks like this:
CxHyOz + O2 (excess) → x CO2 + y H2O
This means we need to do the following steps:
Step 1: Calculate the mass of C and H in the compound.
Step 2: Calculate the mass of O in the compound.
Step 3: Determine the lowest whole number ratio of C, H, and O to get the empirical formula.