Chemistry - Thermochemistry Question with Solution | TestHub
ChemistryThermochemistryEnthalpy of CombustionMedium2 minQB
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From the following data, calculate the enthalpy change for the combustion of cyclopropane(g) at 298 K. The enthalpy of formation of CO2(g), H2O(l) and propene(g) are -394, -286 and 20 kJ/mol, respectively. The enthalpy of isomerization of cyclopropane(g) to propene(g) is -33 kJ/mol.
Options:
Answer:
B
Solution:
Propene: C₃H₆ + 9/2O₂ → 3CO₂ + 3H₂O. Δ Hc (propene) = 3(-394) + 3(-286) - 20 = -1182 - 858 - 20 = -2060 kJ.
Cyclopropane → propene releases 33 kJ, so Δ Hc (cyclopropane) = -33 + (-2060) = -2093 kJ/mol. This corresponds to option (b).
Stream:JEESubject:ChemistryTopic:ThermochemistrySubtopic:Enthalpy of Combustion
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