Question

For the gaseous reaction of carbon monoxide and chlorine to form phosgene (COCL2)

Answer 1

This is an incomplete question, here is a complete question.

For the gaseous reaction of carbon monoxide and chlorine to form phosgene (COCl₂)

Perform the following calculations:

A) Calculate ΔS at 298 K (ΔH= -220 kJ/mol and ΔG= -206 kJ/mol

B) Assuming that ΔS and ΔH change little with temperature, calculate ΔG at 450 K.

Answer :

(a) The value of ΔS at 298 K is, -0.0469 kJ/mol.K

(b) The value of ΔG at 450 K is, -199 kJ/mol

Explanation :

(a) According to Gibb's equation:

$\Delta G=\Delta H-T\Delta S$

$\Delta G$ = Gibbs free energy = -206 kJ/mol

$\Delta H$ = enthalpy change  = -220 kJ/mol

$\Delta S$ = entropy change = ?

T = temperature in Kelvin = 298 K

Now put all the given values in the above formula, we get:

$-206kJ/mol=-220kJ/mol-298K\times \Delta S$

$\Delta S=-0.0469kJ/mol.K$

Thus, the value of ΔS at 298 K is, -0.0469 kJ/mol.K

(b) According to Gibb's equation:

$\Delta G=\Delta H-T\Delta S$

$\Delta G$ = Gibbs free energy = ?

$\Delta H$ = enthalpy change  = -220 kJ/mol

$\Delta S$ = entropy change = -0.0469 kJ/mol.K

T = temperature in Kelvin = 450 K

Now put all the given values in the above formula, we get:

$\Delta G=-220kJ/mol-450K\times -0.0469 kJ/mol.K$

$\Delta G=-198.895kJ/mol\approx -199kJ/mol$

Thus, the value of ΔG at 450 K is, -199 kJ/mol