A particular natural gas consists, in mole percents, of 83.0 (methane), 11.2 (ethane), and 5.80 (propane). A 385-L sample of this gas, measured at 23 C and 729mmHg , is burned in an excess of oxygen gas. How much heat, in kJ, is evolved from this combustion reaction?
enthalpies of combustion:
Hydrocarbon fuel
CH4 -890.3
C2H6 -1559.7
C3H8 -2219.1