Answer to Question #319241 in General Chemistry for Karolyn

Question

A gaseous hydrocarbon, in a volume of 23.4 L at 392 K and a pressure of 3.16 atm, reacts in an excess of oxygen to give 165.7 g of H2O and 404.7 g of CO2. Determine the molecular formula of the hydrocarbon

Answer 1

The mass of CO₂ produced is 404.7g and molar mass of CO₂is44.0g/mol .

Calculate the moles of carbon as follows:

mol C= 404.7g CO₂×1/44.010×1/1

=9.196mol

The mass of H₂O produced is 165.7g and molar mass of is 18.015g/mol .

Calculate the moles of hydrogen as follows:

mol H=82.8×1/18.015×2/1

=9.19mol

Since the moles of both are the same, the ratio is 1:1. So the empirical formula is CH