NiCl2 (s) → Ni+2 (aq) + 2 Cl-1 (aq)

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Reaction Type:

Dissociation of an ionic compound in water

Enthalpy of Reaction

[1ΔHf(Ni+2 (aq)) + 2ΔHf(Cl-1 (aq))] - [1ΔHf(NiCl2 (s))]
[1(-53.97) + 2(-167.15)] - [1(-305.33)] = -82.94 kJ
-82.94 kJ     (exothermic)

Entropy Change

[1ΔSf(Ni+2 (aq)) + 2ΔSf(Cl-1 (aq))] - [1ΔSf(NiCl2 (s))]
[1(-128.87) + 2(56.48)] - [1(97.65)] = -113.56 J/K
-113.56 J/K     (decrease in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(Ni+2 (aq)) + 2ΔGf(Cl-1 (aq))] - [1ΔGf(NiCl2 (s))]
[1(-45.61) + 2(-131.25)] - [1(-259.06)] = -49.05 kJ
-49.05 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-49.08 kJ     (spontaneous)

Equilibrium Constant, K (at 298.15 K)

392343417.02
This process is favorable at 25°C.

Enter an initial concentration for the ionic compound. Upon hitting submit, Ksp (392343417.02) will be used to calculate the equilibrium concentration for all species.

NiCl2 Ni+2 Cl-1
Initial M   0 0
Change -x +x +2x
Equilibrium