PbCl2 (s) → Pb+2 (aq) + 2 Cl-1 (aq)

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Reaction Type:

Dissociation of an ionic compound in water

Enthalpy of Reaction

[1ΔHf(Pb+2 (aq)) + 2ΔHf(Cl-1 (aq))] - [1ΔHf(PbCl2 (s))]
[1(-1.7) + 2(-167.15)] - [1(-359.41)] = 23.41 kJ
23.41 kJ     (endothermic)

Entropy Change

[1ΔSf(Pb+2 (aq)) + 2ΔSf(Cl-1 (aq))] - [1ΔSf(PbCl2 (s))]
[1(10.5) + 2(56.48)] - [1(135.98)] = -12.52 J/K
-12.52 J/K     (decrease in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(Pb+2 (aq)) + 2ΔGf(Cl-1 (aq))] - [1ΔGf(PbCl2 (s))]
[1(-24.4) + 2(-131.25)] - [1(-314.18)] = 27.28 kJ
27.28 kJ     (nonspontaneous)

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

Equilibrium Constant, K (at 298.15 K)

1.6614406821e-005
This process is not favorable at 25°C.

Enter an initial concentration for the ionic compound. Upon hitting submit, Ksp (1.6614406821e-005) will be used to calculate the equilibrium concentration for all species.

PbCl2 Pb+2 Cl-1
Initial M   0 0
Change -x +x +2x
Equilibrium