Hg2Br2 (s) → Hg2+2 (aq) + 2 Br-1 (aq)

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Reaction Type:

Dissociation of an ionic compound in water

Enthalpy of Reaction

[1ΔHf(Hg2+2 (aq)) + 2ΔHf(Br-1 (aq))] - [1ΔHf(Hg2Br2 (s))]
[1(172.4) + 2(-121.55)] - [1(-206.9)] = 136.2 kJ
136.20 kJ     (endothermic)

Entropy Change

[1ΔSf(Hg2+2 (aq)) + 2ΔSf(Br-1 (aq))] - [1ΔSf(Hg2Br2 (s))]
[1(84.5) + 2(82.42)] - [1(218.74)] = 30.6 J/K
30.60 J/K     (increase in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(Hg2+2 (aq)) + 2ΔGf(Br-1 (aq))] - [1ΔGf(Hg2Br2 (s))]
[1(153.5) + 2(-103.97)] - [1(-181.08)] = 126.64 kJ
126.64 kJ     (nonspontaneous)

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

Equilibrium Constant, K (at 298.15 K)

6.49228188054127E-23
This process is not favorable at 25°C.

Enter an initial concentration for the ionic compound. Upon hitting submit, Ksp (6.49228188054127E-23) will be used to calculate the equilibrium concentration for all species.

Hg2Br2 Hg2+2 Br-1
Initial M   0 0
Change -x +x +2x
Equilibrium