## 3 SiH4 (g) + 4 NH3 (g) → Si3N4 (s) + 12 H2 (g)

Back to reactions list

## 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.

 SiH4           Mass: g or Gas Volume: L NH3            Mass: g or Gas Volume: L Si3N4          Mass: g H2             Mass: g or Gas Volume: L Heat Released: kJ

## Enthalpy of Reaction

[1ΔHf(Si3N4 (s)) + 12ΔHf(H2 (g))] - [3ΔHf(SiH4 (g)) + 4ΔHf(NH3 (g))]
[1(-743.5) + 12(0)] - [3(30.54) + 4(-46.11)] = -650.68 kJ
-650.68 kJ     (exothermic)

## Entropy Change

[1ΔSf(Si3N4 (s)) + 12ΔSf(H2 (g))] - [3ΔSf(SiH4 (g)) + 4ΔSf(NH3 (g))]
[1(112.97) + 12(130.59)] - [3(204.51) + 4(192.34)] = 297.16 J/K
297.16 J/K     (increase in entropy)

## Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(Si3N4 (s)) + 12ΔGf(H2 (g))] - [3ΔGf(SiH4 (g)) + 4ΔGf(NH3 (g))]
[1(-581.58) + 12(0)] - [3(56.9) + 4(-16.48)] = -686.36 kJ
-686.36 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-739.28 kJ     (spontaneous)

## Equilibrium Constant, K (at 298.15 K)

1.7855024266e+120
This process is favorable at 25°C.