Answer to Question #99753 in Physical Chemistry for Ra

Question

The equilibrium constant for the reaction :
H₂(g)+S(s)⇔H₂S(g) is 20.0 at 925K and 10.25 at 1000K, respectively.
To calculate the standard enthalpy of reaction.

Answer 1

1. ∂lnK / ∂T = ΔH/(RT²)
2. After integration: ln(K₂/K₁) = ΔH/R • (1/T₁-1/T₂) = ΔH/R • (T₂-T₁)/(T_1•T₂)
3. Hence ΔH equals: ΔH = ln(K2/K1) • R • (T₁T₂)/(T₂-T₁) = -0,668 • 8,314 • (9,25•10⁵)/75 = - 68496 = -68,5 kJ/mol

Good luck!