NH4F (s) → NH4+1 (aq) + F-1 (aq)

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Reaction Type:

Dissociation of an ionic compound in water

Enthalpy of Reaction

[1ΔHf(NH4+1 (aq)) + 1ΔHf(F-1 (aq))] - [1ΔHf(NH4F (s))]
[1(-132.51) + 1(-332.6)] - [1(-463.96)] = -1.15000000000003 kJ
-1.15 kJ     (exothermic)

Entropy Change

[1ΔSf(NH4+1 (aq)) + 1ΔSf(F-1 (aq))] - [1ΔSf(NH4F (s))]
[1(113.39) + 1(-13.8)] - [1(71.96)] = 27.63 J/K
27.63 J/K     (increase in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(NH4+1 (aq)) + 1ΔGf(F-1 (aq))] - [1ΔGf(NH4F (s))]
[1(-79.37) + 1(-278.8)] - [1(-348.78)] = -9.39000000000004 kJ
-9.39 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-9.39 kJ     (spontaneous)

Equilibrium Constant, K (at 298.15 K)

44.1721321945359
This process is favorable at 25°C.

Enter an initial concentration for the ionic compound. Upon hitting submit, Ksp (44.1721321945359) will be used to calculate the equilibrium concentration for all species.

NH4F NH4+1 F-1
Initial M   0 0
Change -x +x +x
Equilibrium