Question

I am having trouble with this equation.

"A 2.39 gram sample of safrole is dissolved in 103 grams of the solvent DPE and this solution has a freezing point of 25.71C. Pure DPE has a freezing point of 26.84 and a value of Kf=8C/molal. Calculate the molar mass of safrole.

Answer 1

The depression in freezing point = 26.84 - 25.71 = 1.13^oC

The molar mass of Safrole can be calculated using the formula :

M = (Kf x w2 x 1000) / (Delta Tf x w1)

where M is the molar mass of safrole

kf is the freezing point constant

w2 is the amount of safrole dissolved

Delta Tf is the depression in freezing point

w1 is the mass of DPE

So putting all the values we get ,

M = ( 8 x 2.39 x 1000) / (1.13 x 103)

M = 164.275 g/mol

So the molar mass of safrole is 164.275 g/mol