Fe2O3 (s hematite) + 6 HNO3 (aq) → 2 Fe(NO3)3 (aq) + 3 H2O (ℓ)

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Reaction Type:

Double Displacement

Stoichiometry

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Fe2O3          Mass: g
HNO3           Mass: g  or Solution Volume: mL of Concentration: mol/L
Fe(NO3)3       Mass: g  or Solution Volume: mL of Concentration: mol/L
H2O            Mass: g

Enthalpy of Reaction

[2ΔHf(Fe(NO3)3 (aq)) + 3ΔHf(H2O (ℓ))] - [1ΔHf(Fe2O3 (s hematite)) + 6ΔHf(HNO3 (aq))]
[2(-670.61) + 3(-285.83)] - [1(-824.25) + 6(-207.36)] = -130.3 kJ
-130.30 kJ     (exothermic)

Entropy Change

[2ΔSf(Fe(NO3)3 (aq)) + 3ΔSf(H2O (ℓ))] - [1ΔSf(Fe2O3 (s hematite)) + 6ΔSf(HNO3 (aq))]
[2(123.43) + 3(69.91)] - [1(87.4) + 6(146.44)] = -509.45 J/K
-509.45 J/K     (decrease in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[2ΔGf(Fe(NO3)3 (aq)) + 3ΔGf(H2O (ℓ))] - [1ΔGf(Fe2O3 (s hematite)) + 6ΔGf(HNO3 (aq))]
[2(-338.62) + 3(-237.18)] - [1(-742.24) + 6(-111.34)] = 21.5 kJ
21.50 kJ     (nonspontaneous)

From ΔG = ΔH - TΔS:
21.59 kJ     (nonspontaneous)

Equilibrium Constant, K (at 298.15 K)

1.71061932886181E-04
This process is not favorable at 25°C.

Reference(s):

Zumdahl, Steven and Zumdahl, Susan A. Chemistry 9th ed.; Brooks/Cole: Belmont, CA, 2014; p 131.

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