BaCl2 (s) → Ba+2 (aq) + 2 Cl-1 (aq)

Reaction Type: Dissociation of an ionic compound in water

Enthalpy of Reaction

[1ΔHf(Ba+2 (aq)) + 2ΔHf(Cl-1 (aq))] - [1ΔHf(BaCl2 (s))]
[1(-537.64) + 2(-167.15)] - [1(-858.14)] = -13.8000000000001 kJ
-13.80 kJ     (exothermic)

Entropy Change

[1ΔSf(Ba+2 (aq)) + 2ΔSf(Cl-1 (aq))] - [1ΔSf(BaCl2 (s))]
[1(9.62) + 2(56.48)] - [1(123.68)] = -1.10000000000001 J/K
-1.10 J/K     (decrease in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(Ba+2 (aq)) + 2ΔGf(Cl-1 (aq))] - [1ΔGf(BaCl2 (s))]
[1(-560.74) + 2(-131.25)] - [1(-810.44)] = -12.8 kJ
-12.80 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-13.47 kJ     (spontaneous)

Equilibrium Constant, K (at 298.15 K)

174.81864839
When K = 1, the reaction is at equilibrium. The larger K is, the more product favored the reaction is at this temperature. The smaller K is, the more reactant favored the reaction is at this temperature. K is calculated from Grxn = -RTlnK, where R = 8.314 J K-1 mol-1.