Your compound's empirical formula will be
So, you know that your compound contains only carbon, hydrogen, and oxygen. Its combustion reaction will only produce carbon dioxide,
This means that all the carbon that the compound contained will now be a part of the carbon dioxide, and all the hydrogen that the compound contained is now a part of the water.
Use carbon dioxde's molar mass to determine how many moles your reaction produced
SInce every 1 mole of
Do the same for water.
This time, 1 mole of water contains 2 moles of hydrogen so you have
Use hydrogen's molar to see how many grams you had
Use the total mass of the sample to determine how much oxygen you had
Since you already know how many moles of carbon and hydrogen the sample contained, use oxygen's molar masses to calculate how many moles you had
Divide the number of moles of each element by the smallest of the group to determine the mole ratios that existed in the sample
Your sample looked like this
Since you can't have fractional subscripts in the empirical formula, multiply all by 2 to get