Freezing point depression of Stearic Acid?

Question

I just found it to be .512 °C per molal solution by experimental data. Is that approximately correct?

*Is stunned by the fact that wikipedia is missing any information about anything*

Answer 1

seems awfully low.  I would think it would be 1.86 plus something for the ionization constant.  With stearic acid that would be low.

I wonder if all your material is in solution.

Answer 2

I must not understand something here. Stearic acid is a solid that's insoluble in water. The freezing point depression constant has to do with the SOLVENT, not a solute. The only effect of the solute is its molality in solution.

Answer 3

You did mean the cryoscopic constant of stearic acid, right? Not the calculation for the freezing-point depression of water by stearic acid?

I did a theoretical calculation for stearic acid using the formula -R*(T_m)^2*M/(delta H_f)

where R = gas constant, T_m = melting point, M = molecular mass, and delta H_f = standard enthalpy change of fusion

using the following values

R = 8.314472

T_m = 343 (K)

M = 0.28448 (must be expressed in kg/mol, not g/mol)

delta H_f = 60000 to 70000 (expressed in J/mol; the NIST WebBook doesn't have accurate data)

giving a result varying from about -4.0 to -4.6. So I guess your figure is off by a factor of ten...

(Of course, I could be wrong...)