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← JEE Main 2022 · 25 Jul · Shift 1
ChemistryInteger+4 / -1Question 82 of 90

JEE Main 2022 · 25 Jul · Shift 1, Chemistry question 82

The enthalpy of combustion of propane, graphite and dihydrogen at 298 K are −2220.0-2220.0 kJ mol−1^{-1}, −393.5-393.5 kJ mol−1^{-1} and −285.8-285.8 kJ mol−1^{-1} respectively. The magnitude of enthalpy of formation of propane (C3H8\mathrm{C_3H_8}) is ______ kJ mol−1^{-1}. (Nearest integer)

Answer and worked solution

Official answer: 104

Hess. ΔfH=3(−393.5)+4(−285.8)+2220=−103.7\Delta_fH=3(-393.5)+4(-285.8)+2220=-103.7 kJ mol−1^{-1}, magnitude 104.

Answer: 104