KBr (s) → K+1 (aq) + Br-1 (aq)

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Reaction Type:

Dissociation of an ionic compound in water

Enthalpy of Reaction

[1ΔHf(K+1 (aq)) + 1ΔHf(Br-1 (aq))] - [1ΔHf(KBr (s))]
[1(-252.4) + 1(-121.55)] - [1(-392.17)] = 18.22 kJ
18.22 kJ     (endothermic)

Entropy Change

[1ΔSf(K+1 (aq)) + 1ΔSf(Br-1 (aq))] - [1ΔSf(KBr (s))]
[1(102.5) + 1(82.42)] - [1(96.44)] = 88.48 J/K
88.48 J/K     (increase in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(K+1 (aq)) + 1ΔGf(Br-1 (aq))] - [1ΔGf(KBr (s))]
[1(-283.3) + 1(-103.97)] - [1(-379.2)] = -8.06999999999999 kJ
-8.07 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-8.16 kJ     (spontaneous)

Equilibrium Constant, K (at 298.15 K)

25.934716243
This process is favorable at 25°C.

Enter an initial concentration for the ionic compound. Upon hitting submit, Ksp (25.934716243) will be used to calculate the equilibrium concentration for all species.

KBr K+1 Br-1
Initial M   0 0
Change -x +x +x
Equilibrium