Al2(SO4)3 (aq) + 6 NaOH (aq) → 2 Al(OH)3 (s) + 3 Na2SO4 (aq)

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Reaction Type:

Double Displacement

Stoichiometry

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Al2(SO4)3      Mass: g  or Solution Volume: mL of Concentration: mol/L
NaOH           Mass: g  or Solution Volume: mL of Concentration: mol/L
Al(OH)3        Mass: g
Na2SO4         Mass: g
Heat Released: kJ

Enthalpy of Reaction

[2ΔHf(Al(OH)3 (s)) + 3ΔHf(Na2SO4 (aq))] - [1ΔHf(Al2(SO4)3 (aq)) + 6ΔHf(NaOH (aq))]
[2(-1284.49) + 3(-1389.47)] - [1(-3790.55) + 6(-470.09)] = -126.299999999999 kJ
-126.30 kJ     (exothermic)

Entropy Change

[2ΔSf(Al(OH)3 (s)) + 3ΔSf(Na2SO4 (aq))] - [1ΔSf(Al2(SO4)3 (aq)) + 6ΔSf(NaOH (aq))]
[2(71.13) + 3(138.08)] - [1(-583.26) + 6(48.25)] = 850.26 J/K
850.26 J/K     (increase in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[2ΔGf(Al(OH)3 (s)) + 3ΔGf(Na2SO4 (aq))] - [1ΔGf(Al2(SO4)3 (aq)) + 6ΔGf(NaOH (aq))]
[2(-1305.83) + 3(-1268.43)] - [1(-3204.57) + 6(-419.18)] = -697.299999999999 kJ
-697.30 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-379.81 kJ     (spontaneous)

Equilibrium Constant, K (at 298.15 K)

1.4739140858e+122
This process is favorable at 25°C.

Reference(s):

Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 89.

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