calculating empirical formula of organic compounds

This is the balanced chemical equation for the burning of CxHy

CxHy + 2 O2 -> CO2 + y/2 H20

We need to find x and y, which is the amount of moles of C in CO2 and H in H20

We are trying to find the empirical formula of a compound that burns to produce 16.9 g of CO2 and 3.46 grams of H20.

First, convert the mass ( grams)  of CO2 and H20 into moles.  You should get 0.384 moles of CO2 and 0.192 moles of H20

Secondly, we need to find out how many moles of C are in CO2 and how many moles of H are in H20.   There are 0.384 moles of carbon and hydrogen.  Because they are the same number, when you divide them you get 1. So, the empirical formula is CH.

There are review sheets with plenty of questions for you to practice.  There is a quiz next class.  Here are some videos with empirical formula and molecular formula