def P_RK_IG(V, T, do_ideal_gas=False):
   R = 0.0821  # L-atm/K
   Pc = 37.2   # atm
   Tc = 132.5  # K

   a = 0.427 * pow(R,2) * pow(Tc,2.5) / Pc
   b = 0.0866 * R * Tc / Pc

   # Compute in atm
   P_ig = R * T / V
   P_rk = R * T / (V-b) - a/(V*(V+b)*pow(T,0.5))

   # Convert to Pascals
   if do_ideal_gas:
      return P_ig * 101325
   else:
      return P_rk * 101325

for T in range(490,511,10):
   V = 4.0
   while V < 8:
      print("----- Temperature: " + str(T) + " K")
      print("P_ig: " + str(P_RK_IG(V,T,True)) + " Pa")
      print("P_rk: " + str(P_RK_IG(V,T)) + " Pa")
      V = V + 2.0