Question

For the gaseous reaction of carbon monoxide and chlorine to form phosgene (COC₂), perform the

following calculations.
(a) Calculate the AS at 298 K (AH =-220. kJ/mol and AG =-206 kJ/mol).
kJ/mol K
0
(b) Assuming that AS and AH change little with temperature, calculate AG at 450. K.
kJ/mol

Answer 1

(a) To calculate the AS at 298 K, we can use the Gibbs-Helmholtz equation:
ΔG = ΔH - TΔS

Rearranging this equation to solve for ΔS, we get:

ΔS = (ΔH - ΔG) / T

Substituting the given values, we get:

ΔS = (-220 kJ/mol - (-206 kJ/mol)) / (298 K) = -0.47 kJ/(mol K)

Therefore, the AS at 298 K is -0.47 kJ/(mol K).

(b) Assuming that AS and AH change little with temperature, we can use the equation:

ΔG = ΔH - TΔS

To calculate the AG at 450 K.

Substituting the given values, we get:

ΔG = -220 kJ/mol - (450 K)(-0.47 kJ/(mol K)) = -2.2 kJ/mol

Therefore, the AG at 450 K is -2.2 kJ/mol.