AgSCN (s) → Ag+1 (aq) + SCN-1 (aq)

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Reaction Type:

Dissociation of an ionic compound in water

Enthalpy of Reaction

[1ΔHf(Ag+1 (aq)) + 1ΔHf(SCN-1 (aq))] - [1ΔHf(AgSCN (s))]
[1(105.58) + 1(76.44)] - [1(87.86)] = 94.16 kJ
94.16 kJ     (endothermic)

Entropy Change

[1ΔSf(Ag+1 (aq)) + 1ΔSf(SCN-1 (aq))] - [1ΔSf(AgSCN (s))]
[1(72.68) + 1(144.35)] - [1(130.96)] = 86.07 J/K
86.07 J/K     (increase in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(Ag+1 (aq)) + 1ΔGf(SCN-1 (aq))] - [1ΔGf(AgSCN (s))]
[1(77.12) + 1(92.68)] - [1(101.38)] = 68.42 kJ
68.42 kJ     (nonspontaneous)

From ΔG = ΔH - TΔS:
68.50 kJ     (nonspontaneous)

Equilibrium Constant, K (at 298.15 K)

1.0295978427e-012
This process is not favorable at 25°C.

Enter an initial concentration for the ionic compound. Upon hitting submit, Ksp (1.0295978427e-012) will be used to calculate the equilibrium concentration for all species.

AgSCN Ag+1 SCN-1
Initial M   0 0
Change -x +x +x
Equilibrium