ΔG° = ΔH° - TΔS°

Question

For the reaction

4HCl(g) + O₂(g)2H₂O(g) + 2Cl₂(g)

H° = -114.4 kJ and S° = -128.9 J/K

The standard free energy change for the reaction of 1.62 moles of HCl(g) at 261 K, 1 atm would be ___ kJ.

This reaction is (reactant, product) _____ favored under standard conditions at 261 K.

Assume that H° and S° are independent of temperature.

Answer 1

∆G = ∆H - T∆S

∆G = ?

∆H = -114.4 kJ

∆S = -128.9 J/K = -0.1289 kJ/K

T = 261K

Solving for ∆G we have..

∆G = -114.4 kJ - (-0.1289 kJ/K * 261K) = -114.4 kJ + 33.6 kJ

∆G = - 80.8 kJ for the 1.62 moles of HCl(g)

This reaction is product favored under these conditions (-∆G indicates spontaneous reaction)