Question

Derive a formula for the molar mass of the solute in terms of the freezing point depression, deltaT, the freezing-point constant, Kf, and the masses of solvent, msolvent, and solute, msolute, used in an experiment like this one. SHow your work and include all unites in your final formula.

This is my attemps at the formula:

ΔT = Kf * (msolvent + msolute / nsolvent + nsolute)

Answer 1

I think what you need to do is as follows:
delta T = Kf*molality
molality = mols solute/kg solvent
mols solute = mass solute/molar mass.
Substitute equation 2 into equation 1 for molality.
Then, substitute mols solute into the resulting equation and solve for molar mass.

Answer 2

I see, thanks a lot Bob!