Cu (s) + 4 HNO3 (aq) → Cu(NO3)2 (aq) + 2 NO2 (g) + 2 H2O (ℓ)

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Stoichiometry

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Cu             Mass: g
HNO3           Mass: g  or Solution Volume: mL of Concentration: mol/L
Cu(NO3)2       Mass: g
NO2            Mass: g  or Gas Volume: L
H2O            Mass: g
Heat Released: kJ

Enthalpy of Reaction

[1ΔHf(Cu(NO3)2 (aq)) + 2ΔHf(NO2 (g)) + 2ΔHf(H2O (ℓ))] - [1ΔHf(Cu (s)) + 4ΔHf(HNO3 (aq))]
[1(-349.95) + 2(33.18) + 2(-285.83)] - [1(0) + 4(-207.36)] = -25.8099999999999 kJ
-25.81 kJ     (exothermic)

Entropy Change

[1ΔSf(Cu(NO3)2 (aq)) + 2ΔSf(NO2 (g)) + 2ΔSf(H2O (ℓ))] - [1ΔSf(Cu (s)) + 4ΔSf(HNO3 (aq))]
[1(193.3) + 2(239.95) + 2(69.91)] - [1(33.15) + 4(146.44)] = 194.11 J/K
194.11 J/K     (increase in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(Cu(NO3)2 (aq)) + 2ΔGf(NO2 (g)) + 2ΔGf(H2O (ℓ))] - [1ΔGf(Cu (s)) + 4ΔGf(HNO3 (aq))]
[1(-157.16) + 2(51.3) + 2(-237.18)] - [1(0) + 4(-111.34)] = -83.5600000000001 kJ
-83.56 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-83.68 kJ     (spontaneous)

Equilibrium Constant, K (at 298.15 K)

4.3640850798e+014
This process is favorable at 25°C.

Reference(s):

Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 341.

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