A certain fuel mixture is made up of the following gases in percent by volume: 30.6% propane (C₃H₈), 52.3% butane (C₄H₁₀), and the rest pentane (C₅H₁₂). The mixture is stored at 298 K and 745 mmHg in a 2.50 L gas tank. When the fuel mixture is subjected to complete combustion, calculate the total heat that is emitted. Note that water vapor is produced in the combustion reaction.
                             ΔH°_f (kJ/mol)
C₃H₈(g)               –103.85
C₄H₁₀(g)              –125.7
C₅H₁₂(g)              –146.9
O₂(g)                    0
CO₂(g)                –393.5
H₂O(g)                –241.8