31)
Substituting this value of molality in equation (1 34) we get:
DTf = 
f
2
2
1
 
 
/
/1000
K
M
w
w
DTf = 
f
2
2
1
 × 
 × 1000
 × 
K
M
w
w
(1 35)
M2 = 
f
2
f
1
 × 
 × 1000 
 
 × 

K
T
w
w
(1 36)
Thus for determining the molar mass of the solute we should know
the quantities w1, w2, DTf, along with the molal freezing point depression
constant