At constant pressure, the combustion of 20.0 g of C₂H₆(g)releases 1036 kJ of heat. What is ΔH for the reaction given below? 2C₂H₆(g)+ 7O₂(g)→ 4CO₂(g)+ 6H₂O(l)

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Quizplus · Accepted Answer

The combustion of 20.0 g of C₂H₆ releases 1036 kJ. The molar mass of C₂H₆ is 30.07 g/mol, so 20.0 g corresponds to 20.0/30.07 = 0.665 mol. The heat released per mole is 1036 kJ / 0.665 mol = 1558 kJ/mol. For the reaction 2C₂H₆, the ΔH is 2 * 1558 kJ/mol = 3116 kJ/mol, which is closest to -3120 kJ/mol.

At Constant Pressure, the Combustion of 20