Question

Given the reference thermodynamic data below taken at 25°C, calculate the value of the equilibrium constant for the reaction shown at 800.0°C COCI, (g) 2 CO (g) + Cl2 (g) AG° = 69.46 kJ AH° = 110.38 kJ AS° = 137.24 J/K at 800.0°C

Answer 1

ΔH = 110.38 KJ
ΔS = 137.24 J/K
= 0.13724 KJ/K
T= 800.0 oC
= (800.0+273) K
= 1073 K

use:
ΔG = ΔH - T*ΔS
ΔG = 110.38 - 1073.0 * 0.1372
ΔG = -36.8785 KJ

We have:
ΔGo = -36.8785 KJ/mol
ΔGo = -36878.5 J/mol

use:
ΔGo = -R*T*ln Kc
-36878.5 = - 8.314*1073.0* ln(Kc)
ln Kc = 4.1339
Kc = 62.42
Answer: 62.4