Thyroxine, an important hormone that controls the rate of metabolism in the body, can be isolated from the thyroid gland. If 0.455 g of thyroxine is dissolved in 10.0g of benzene, the freezing point of the solution is 5.144 degrees celcius. Pure benzene freezes at 5.444 degrees celcius and has a Kf of 5.12 degrees celcius/m. What is the molar mass of thyroxine?