## Ag2S (s alpha orthorhombic) + 2 HCl (aq) → 2 AgCl (s) + H2S (g)

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## Reaction Type:

Double Displacement

## 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 Ag2S           Mass: g HCl            Mass: g or Solution Volume: mL of Concentration: mol/L AgCl           Mass: g H2S            Mass: g or Gas Volume: L

## Enthalpy of Reaction

[2ΔHf(AgCl (s)) + 1ΔHf(H2S (g))] - [1ΔHf(Ag2S (s alpha orthorhombic)) + 2ΔHf(HCl (aq))]
[2(-127) + 1(-20.17)] - [1(-32.59) + 2(-167.15)] = 92.72 kJ
92.72 kJ     (endothermic)

## Entropy Change

[2ΔSf(AgCl (s)) + 1ΔSf(H2S (g))] - [1ΔSf(Ag2S (s alpha orthorhombic)) + 2ΔSf(HCl (aq))]
[2(96.3) + 1(205.77)] - [1(144.01) + 2(56.48)] = 141.4 J/K
141.40 J/K     (increase in entropy)

## Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[2ΔGf(AgCl (s)) + 1ΔGf(H2S (g))] - [1ΔGf(Ag2S (s alpha orthorhombic)) + 2ΔGf(HCl (aq))]
[2(-109.8) + 1(-33.05)] - [1(-40.67) + 2(-131.25)] = 50.52 kJ
50.52 kJ     (nonspontaneous)

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

## Equilibrium Constant, K (at 298.15 K)

1.4085959715e-009
This process is not 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 128.