## PbS (s) + 2 HCl (aq) → PbCl2 (aq) + H2S (g)

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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 PbS            Mass: g HCl            Mass: g or Solution Volume: mL of Concentration: mol/L PbCl2          Mass: g H2S            Mass: g or Gas Volume: L

## Enthalpy of Reaction

[1ΔHf(PbCl2 (aq)) + 1ΔHf(H2S (g))] - [1ΔHf(PbS (s)) + 2ΔHf(HCl (aq))]
[1(-336) + 1(-20.17)] - [1(-98.32) + 2(-167.15)] = 76.45 kJ
76.45 kJ     (endothermic)

## Entropy Change

[1ΔSf(PbCl2 (aq)) + 1ΔSf(H2S (g))] - [1ΔSf(PbS (s)) + 2ΔSf(HCl (aq))]
[1(123.46) + 1(205.77)] - [1(91.34) + 2(56.48)] = 124.93 J/K
124.93 J/K     (increase in entropy)

## Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(PbCl2 (aq)) + 1ΔGf(H2S (g))] - [1ΔGf(PbS (s)) + 2ΔGf(HCl (aq))]
[1(-286.9) + 1(-33.05)] - [1(-96.73) + 2(-131.25)] = 39.28 kJ
39.28 kJ     (nonspontaneous)

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

## Equilibrium Constant, K (at 298.15 K)

1.3123776242e-007
This process is not favorable at 25°C.

## Reference(s):

Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 185.
Halka, Monica and Nordstrom, Brian. Metals & Metalloids; Infobase Publishing: New York, NY, 2011; pg. 60.