For the reaction

I_2(s)+Cl_2(g) ==> 2ICl(g)
ÄH= 36kJ, ÄS= 158.8J/K at 25° C. Calculate the temperature at which Keq is 4.0*10^3.

ÄG= ÄH- TÄS
= 36 - (298)(0.1588)
= -11.32

ÄG= -RTlnK
-11.32= -8.31Tln(4*10^3)
-11.32= -6892.35 T
T= .00164

correct answer = 128°C
=

T = ΔH/(ΔS - R*ln(Keq))