show steps and equations used please

1.00g of an unknown substance dissolved in 100g of benzene lowers its freezing point by 0.32C. Calculate the molar mass of the unknown. We are told Tr=Kfm=0.32C and from Table 105Kf for benzene is 5.12Cm1. Rearranging the equation Tf=mKrgives: Substama is un Known Can't use i anyways. molality, m=Kkgsolventmolsolate 0.32=(5.12)m mol of solute - Now use this to calculate the molar mass: molarmass=molesofsolutemassofsolute