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Homework Statement
6g of non-volatile solute dissolved in 500g of water freezes at 272.64K. What is the molar mass of the solute?
Data given-
Tsolution = 272.64K
Kf = 1.8
wsolute = 6g
wsolvent = 500g
2. Homework Equations
∆Tf = T0 -Tsolution
∆Tf = Kf × molality (m)
The Attempt at a Solution
∆Tf = T0-Tsolution
= 273-272.64
=0.36
∆Tf = Kf x m
⇒0.36 = 1.8 × m
∴m = 0.36 / 1.8
= 0.05 m
molality = ( wsolute / msolute ) × (1000 / wsolvent )
⇒0.05 = ( 6 / msolute ) × ( 1000 / 500 )
∴msolute = ( 6 / 0.05 ) × ( 1000 / 500 )
= 12 / 0.05
= 240 g
Is this correct?