## Sc2O3 (s) + 3 H2O (ℓ) → 2 Sc(OH)3 (s)

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Synthesis

## Stoichiometry

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 Heat Added: kJ Sc2O3          Mass: g H2O            Mass: g Sc(OH)3        Mass: g

## Enthalpy of Reaction

[2ΔHf(Sc(OH)3 (s))] - [1ΔHf(Sc2O3 (s)) + 3ΔHf(H2O (ℓ))]
[2(-1363.57)] - [1(-1908.82) + 3(-285.83)] = 39.1700000000001 kJ
39.17 kJ     (endothermic)

## Entropy Change

[2ΔSf(Sc(OH)3 (s))] - [1ΔSf(Sc2O3 (s)) + 3ΔSf(H2O (ℓ))]
[2(100.42)] - [1(76.99) + 3(69.91)] = -85.88 J/K
-85.88 J/K     (decrease in entropy)

## Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[2ΔGf(Sc(OH)3 (s))] - [1ΔGf(Sc2O3 (s)) + 3ΔGf(H2O (ℓ))]
[2(-1233.44)] - [1(103.97) + 3(-237.18)] = -1859.31 kJ
-1,859.31 kJ     (spontaneous)

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

## Equilibrium Constant, K (at 298.15 K)

approaches infinity
This process is favorable at 25°C.

## Reference(s):

Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change 4th ed.; McGraw-Hill: Boston, MA, 2006; p 127.