A particular natural gas exists, in mole percents, of 83.0% CH4, 11.2% C2H6, and 5.8% C3H8. A 380 L sample of this gas measured at 22.2 degrees Celsius and 745 mm Hg, is burned at constant pressure in an excess of oxygen gas. How much heat, in kilojoules, is evolved in the combustion reaction?