PCl5(g)Â Â <-----------------> PCl3(g) +
Cl2(g)
ΔGorxn = ΔGoproducts
- ΔGoreactants
             Â
= (- 267.8 + 0) - (-305.0)
          =
37.2 kJ/mol
ΔGo = - R T ln K
37.2 = - 8.314x 10^-3 x 523 x ln K
K = 1.926 x 10^-4
concentration of PCl5 = 0.213 / 3.40 = 0.0626
PCl5(g) -----------------> PCl3(g) + Cl2(g)
0.0626Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
0Â Â Â Â Â Â Â Â Â Â Â
0
0.0626 -
x                          Â
x           Â
x
K = x^2 / 0.0626 - x
1.926 x 10^-4 = x^2 / 0.0626 - x
x = 0.00337
equilibrium concentrations :
[PCl5] = 0.0626 - x = 0.0592 M
[PCl3] = x = 0.00337 M
