## 2 MoCl5 (s) + 5 Na2S (s) → 2 MoS2 (s) + 10 NaCl (s) + 1 S (s rhombic)

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## Stoichiometry

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 MoCl5          Mass: g Na2S           Mass: g MoS2           Mass: g NaCl           Mass: g S              Mass: g Heat Released: kJ

## Enthalpy of Reaction

[2ΔHf(MoS2 (s)) + 10ΔHf(NaCl (s)) + 1ΔHf(S (s rhombic))] - [2ΔHf(MoCl5 (s)) + 5ΔHf(Na2S (s))]
[2(-235.14) + 10(-410.99) + 1(0)] - [2(-527.18) + 5(-373.21)] = -1659.77 kJ
-1,659.77 kJ     (exothermic)

## Entropy Change

[2ΔSf(MoS2 (s)) + 10ΔSf(NaCl (s)) + 1ΔSf(S (s rhombic))] - [2ΔSf(MoCl5 (s)) + 5ΔSf(Na2S (s))]
[2(62.59) + 10(72.38) + 1(31.92)] - [2(238.49) + 5(97.91)] = -85.63 J/K
-85.63 J/K     (decrease in entropy)

## Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[2ΔGf(MoS2 (s)) + 10ΔGf(NaCl (s)) + 1ΔGf(S (s rhombic))] - [2ΔGf(MoCl5 (s)) + 5ΔGf(Na2S (s))]
[2(-225.94) + 10(-384.05) + 1(0)] - [2(-422.58) + 5(-359.82)] = -1648.12 kJ
-1,648.12 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-1634.24 kJ     (spontaneous)

## Equilibrium Constant, K (at 298.15 K)

5.6780357653e+288
This process is favorable at 25°C.

## Reference(s):

Atkins, Jones, and Laverman. Chemical Principles 6th ed.; W.H. Freeman and Company: New York, NY, 2013; p F94.