## 2 Ca3(PO4)2 (s beta) + 6 SiO2 (s quartz) + 10 C (s graphite) → P4 (g) + 6 CaSiO3 (s wollastonite) + 10 CO (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.

 Heat Added: kJ Ca3(PO4)2      Mass: g SiO2           Mass: g C              Mass: g P4             Mass: g or Gas Volume: L CaSiO3         Mass: g CO             Mass: g or Gas Volume: L

## Enthalpy of Reaction

[1ΔHf(P4 (g)) + 6ΔHf(CaSiO3 (s wollastonite)) + 10ΔHf(CO (g))] - [2ΔHf(Ca3(PO4)2 (s beta)) + 6ΔHf(SiO2 (s quartz)) + 10ΔHf(C (s graphite))]
[1(128.87) + 6(-1634.94) + 10(-110.54)] - [2(-4120.82) + 6(-910.94) + 10(0)] = 2921.11 kJ
2,921.11 kJ     (endothermic)

## Entropy Change

[1ΔSf(P4 (g)) + 6ΔSf(CaSiO3 (s wollastonite)) + 10ΔSf(CO (g))] - [2ΔSf(Ca3(PO4)2 (s beta)) + 6ΔSf(SiO2 (s quartz)) + 10ΔSf(C (s graphite))]
[1(128.87) + 6(81.92) + 10(197.9)] - [2(235.98) + 6(41.84) + 10(5.69)] = 1819.49 J/K
1,819.49 J/K     (increase in entropy)

## Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(P4 (g)) + 6ΔGf(CaSiO3 (s wollastonite)) + 10ΔGf(CO (g))] - [2ΔGf(Ca3(PO4)2 (s beta)) + 6ΔGf(SiO2 (s quartz)) + 10ΔGf(C (s graphite))]
[1(72.38) + 6(-1549.71) + 10(-137.28)] - [2(-3884.84) + 6(-856.67) + 10(0)] = 2311.02 kJ
2,311.02 kJ     (nonspontaneous)

From ΔG = ΔH - TΔS:
2378.63 kJ     (nonspontaneous)

## Equilibrium Constant, K (at 298.15 K)

0
This process is not 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.