(NH4)2SO4 (aq) + 2 NaOH (aq) → Na2SO4 (aq) + 2 H2O (ℓ) + 2 NH3 (g)

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Reaction Type:

Double Displacement/Decomposition of Ammonium Hydroxide

Stoichiometry

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Heat Added: kJ
(NH4)2SO4      Mass: g  or Solution Volume: mL of Concentration: mol/L
NaOH           Mass: g  or Solution Volume: mL of Concentration: mol/L
Na2SO4         Mass: g
H2O            Mass: g
NH3            Mass: g  or Gas Volume: L

Enthalpy of Reaction

[1ΔHf(Na2SO4 (aq)) + 2ΔHf(H2O (ℓ)) + 2ΔHf(NH3 (g))] - [1ΔHf((NH4)2SO4 (aq)) + 2ΔHf(NaOH (aq))]
[1(-1389.47) + 2(-285.83) + 2(-46.11)] - [1(-1174.29) + 2(-470.09)] = 61.1200000000003 kJ
61.12 kJ     (endothermic)

Entropy Change

[1ΔSf(Na2SO4 (aq)) + 2ΔSf(H2O (ℓ)) + 2ΔSf(NH3 (g))] - [1ΔSf((NH4)2SO4 (aq)) + 2ΔSf(NaOH (aq))]
[1(138.08) + 2(69.91) + 2(192.34)] - [1(246.86) + 2(48.25)] = 319.22 J/K
319.22 J/K     (increase in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(Na2SO4 (aq)) + 2ΔGf(H2O (ℓ)) + 2ΔGf(NH3 (g))] - [1ΔGf((NH4)2SO4 (aq)) + 2ΔGf(NaOH (aq))]
[1(-1268.43) + 2(-237.18) + 2(-16.48)] - [1(-903.37) + 2(-419.18)] = -34.02 kJ
-34.02 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-34.06 kJ     (spontaneous)

Equilibrium Constant, K (at 298.15 K)

912804.5075
This process is favorable at 25°C.

Reference(s):

Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 138.

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