Thermodynamics of Polymerization

The ceiling concentration for the radical polymerization of styrene in solution is 1x10^-6 M at 25°C.  For the radical polymerization of the pure monomer (no solvent), the ceiling temperature is 310°C.  Calculate ΔH° (in kJ/mo) and ΔS° (in J/Kmol).

k_p (rate of propagation)=134 M^-1 s^-1 (at 298 K).
boiling point=145°C
density=.909g/mL
MW=104.15g/mol
R=8.314J/Kmol


I'm not understanding how to approach this.  Can I assume that ΔG° is = at 298K?  Then use 1/[M]_c, the ceiling concentration, as my rate constant, since at equilibrium for radical polymerizations the equilibrium constant is that?

I tried -(8.314)(298)ln(1/1x10^-6)

but I'm not sure that's right.

Any help is appreciated.