The enthalpy of formation for CH₄(g), C(g) and H(g) are -75,717 and 218 kJ mol⁻¹, respectively. The enthalpy… · ABC26PH0849

Subject: Physical Chemistry · Chapter: Thermodynamics · Topic: Thermodynamics – General · Exam: JAM 2001-2022 · Marks: 2 · Difficulty: Medium

The enthalpy of formation for $\mathrm{CH}_{4}(\mathrm{g}), \mathrm{C}(\mathrm{g})$ and $\mathrm{H}(\mathrm{g})$ are $-75,717$ and $218 \mathrm{kJ} \mathrm{mol}^{-1}$, respectively. The enthalpy of the $\mathrm{C}-\mathrm{H}$ bond in $\mathrm{kJ} \mathrm{mol}^{-1}$ is ____ .
Answer
SELF-PRACTICE — the source book printed no answer.

Nothing is invented here, so this question has no answer on record.

Explanation
Answer: 416 kJ mol⁻¹ — CH₄(g) → C(g) + 4H(g): ΔH = 717 + 4 × 218 − (−75) = 1664 kJ mol⁻¹; C–H = 1664/4 = 416 kJ mol⁻¹.

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