0.39 g of a hydrocarbon on combustion produces 1.32 g CO2 and 0.27 g of H2O.

Question

0.39 g of hydrocarbon on combustion produces 1.32 g CO₂ and 0.27 g H₂​​​​​​O. Calculate the percentage of C and H in the hydrocarbon.

Answer 1

A hydrocarbon is a compound which consists of carbon and hydrogen only. It undergoes combustion forming carbon dioxide and water as products.

Given mass of hydrocarbon on combustion = 0.39

Given mass of CO₂ = 1.32g

Given mass of H₂O = 0.27g

Mass of carbon in 0.39g of CO₂ = (12/44) x (1.32) =  0.36g CO₂

Mass of hydrogen in 0.27 g of H₂O= (2/18) x (0.27) = 0.03g H₂O

Percentage of C in hydrocarbon = (0.36/0.39) x (100) = 92.30%

Percentage of H in hydrocarbon= (0.03/0.39) x (100) = 7.69%