A 704-L Sample of a Gaseous Hydrocarbon,measured at 1

A 70.4-L sample of a gaseous hydrocarbon,measured at 1.00 atm pressure and 25.0°C,is burned in excess oxygen,liberating 4.06 × 10³ kJ of heat at constant pressure.What is the identity of the hydrocarbon? (R = 0.0821 L ∙ atm/(K ∙ mol) )
Substance
ΔH°_f (kJ/mol)
CO₂(g)
-393.5
H₂O(l)
-285.8

A) propylene (C₃H₆,ΔH°_f = 20.41 kJ/mol)
B) propane (C₃H₈,ΔH°_f = -104.7 kJ/mol)
C) acetylene (C₂H₂,ΔH°_f = 226.73 kJ/mol)
D) ethylene (C₂H₄,ΔH°_f = 52.47 kJ/mol)
E) ethane (C₂H₆,ΔH°_f = -84.68 kJ/mol)