## S-2 (aq) + 1 H2O (ℓ) → HS-1 (aq) + OH-1 (aq)

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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.

 Heat Added: kJ S-2            Mass: g or Solution Volume: mL of Concentration: mol/L H2O            Mass: g HS-1           Mass: g OH-1           Mass: g

## Enthalpy of Reaction

[1ΔHf(HS-1 (aq)) + 1ΔHf(OH-1 (aq))] - [1ΔHf(S-2 (aq)) + 1ΔHf(H2O (ℓ))]
[1(-17.57) + 1(-229.99)] - [1(33.05) + 1(-285.83)] = 5.21999999999997 kJ
5.22 kJ     (endothermic)

## Entropy Change

[1ΔSf(HS-1 (aq)) + 1ΔSf(OH-1 (aq))] - [1ΔSf(S-2 (aq)) + 1ΔSf(H2O (ℓ))]
[1(62.76) + 1(-10.75)] - [1(-14.64) + 1(69.91)] = -3.26 J/K
-3.26 J/K     (decrease in entropy)

## Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(HS-1 (aq)) + 1ΔGf(OH-1 (aq))] - [1ΔGf(S-2 (aq)) + 1ΔGf(H2O (ℓ))]
[1(12.05) + 1(-157.28)] - [1(85.77) + 1(-237.18)] = 6.18000000000004 kJ
6.18 kJ     (nonspontaneous)

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

## Equilibrium Constant, K (at 298.15 K)

0.082651473022
This process is not favorable at 25°C.

## Reference(s):

Halka, Monica and Nordstrom, Brian. Metals & Metalloids; Infobase Publishing: New York, NY, 2011; p 14.