Solution of 100 g of a substance in 750 grams of the solvent (CCl

_{4}) depresses the freezing point of the solvent by 10.5 K. The freezing point constant for the solvent is 30 K/(mol kg

^{-1}). Determine the molecular weight of the unknown substance.

My thinking of this exercise is the following:

1. The particle concentration is determined: ΔT/Kf, this gives a molality. To turn it into a molarity I devided it by the density of the solvent. So now I have the molarity of the unknown compound, right?.

2. With both the density and the molar mass of solvent known I can calculate how many moles of CCl

_{4} there are present and the volume and further the concentration of CCl

_{4}.

3. Now I should be able to calculate the volume of the unknown substance by c1V1=c2V2 <=> V1 = (c2V2)/c1.

4. Thus I can now calculate how many moles of the substance present and hereby,

5: Calculate molcecular weight by: M = m/n

I am not sure about if some of these steps are correct, but I hope some of you can tell this to me

,

sincerely,

MVS