## 6 HNO3 (aq) + S (s rhombic) → 6 NO2 (g) + H2SO4 (aq) + 2 H2O (ℓ)

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## Stoichiometry

Enter a mass or volume in one of the boxes below. Upon hitting submit, the stoichiometric equivalents will be calculated for the remaining reactants and products. All gases are assumed to be at STP.

 HNO3           Mass: g or Solution Volume: mL of Concentration: mol/L S              Mass: g NO2            Mass: g or Gas Volume: L H2SO4          Mass: g H2O            Mass: g Heat Released: kJ

## Enthalpy of Reaction

[6ΔHf(NO2 (g)) + 1ΔHf(H2SO4 (aq)) + 2ΔHf(H2O (ℓ))] - [6ΔHf(HNO3 (aq)) + 1ΔHf(S (s rhombic))]
[6(33.18) + 1(-909.27) + 2(-285.83)] - [6(-207.36) + 1(0)] = -37.6899999999998 kJ
-37.69 kJ     (exothermic)

## Entropy Change

[6ΔSf(NO2 (g)) + 1ΔSf(H2SO4 (aq)) + 2ΔSf(H2O (ℓ))] - [6ΔSf(HNO3 (aq)) + 1ΔSf(S (s rhombic))]
[6(239.95) + 1(20.08) + 2(69.91)] - [6(146.44) + 1(31.92)] = 689.04 J/K
689.04 J/K     (increase in entropy)

## Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[6ΔGf(NO2 (g)) + 1ΔGf(H2SO4 (aq)) + 2ΔGf(H2O (ℓ))] - [6ΔGf(HNO3 (aq)) + 1ΔGf(S (s rhombic))]
[6(51.3) + 1(-744.63) + 2(-237.18)] - [6(-111.34) + 1(0)] = -243.15 kJ
-243.15 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-243.13 kJ     (spontaneous)

## Equilibrium Constant, K (at 298.15 K)

3.9848070462e+042
This process is favorable at 25°C.