Combustion analysis of an unknown compound containing only carbon and hydrogen p
ID: 757097 • Letter: C
Question
Combustion analysis of an unknown compound containing only carbon and hydrogen produced 1.1385 g of CO2 and 0.5805 g of H2O. What is the empirical formula of the compound?Explanation / Answer
You are given the mass of the hydrocarbon, however, it is hidden in the combustion data.. Hydrocarbon + O2 >>> H20 + CO2 The goal is to find out how many moles of "carbon" are in the CO2 and how many moles of "hydrogen" are in the water. Once you know these numbers, then you should be able to get the empirical formula. Since the hydrocarbon is " burned completely" , then you can do this problem. If it wasn't and this was the only information you had, then you couldn't solve it.. Let's start with the number of moles of carbon.. You have 7.2 liters of CO2 and standard conditions. Here, you would use your gas law equation.. PV=nRT You want to know how many moles of carbon dioxide are present , so solve for "n" n=PV/RT Plugging in the numbers for P,V,R and T. Standard conditions are 100kPa (or 1 bar) @ 273K (or 0°C)..