The heat of total cracking of hydrocarbons, ΔH_TC is defined as ΔH at 298.15 K and 101.325 kPa for the process:
C_nH_m + (2n - m/2)H₂(g) → nCH₄(g)
The values of ΔH_TC is -65.2 kJ for C₂H₆ and -87.4 kJ for C₃H₈. Calculate ΔH (in kJ) for
CH₄(g) + C₃H₈(g) → 2C₂H₆(g)

Question

The heat of total cracking of hydrocarbons, ΔH_TC is defined as ΔH at 298.15 K and 101.325 kPa for the process:

C_nH_m + (2n - m/2)H₂(g) → nCH₄(g)

The values of ΔH_TC is -65.2 kJ for C₂H₆ and -87.4 kJ for C₃H₈. Calculate ΔH (in kJ) for

CH₄(g) + C₃H₈(g) → 2C₂H₆(g)

TestHub · Accepted Answer

The given reactions are: 1. C ₂ H ₆ + H ₂ → 2CH ₄ , with Δ H = -65.2 kJ 2. C ₃ H ₈ + 2H ₂ → 3CH ₄ , with Δ H = -87.4 kJ To find the enthalpy change for the target reaction, we can manipulate these equations. The target reaction's enthalpy change is calculated as: Δ H target = Δ H second - 2 × Δ H first Substituting the given values: Δ H target = -87.4 kJ - 2(-65.2 kJ) Δ H target = -87.4 kJ + 130.4 kJ Δ H target = +43 kJ The answer is 0043.

Chemistry - Thermochemistry Question with Solution | TestHub

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