Question

Calculate the molality of a solution of urea in acetic acid if the mole fraction of urea in solution is 0.5

Answer 1

Calculate the molality of a solution of urea in acetic acid if the mole fraction of urea in solution is 0.5.

mole fraction of urea, $x_A$ = 0.5

so, mole fraction of acetic acid, $x_B$= 1 - 0.5 = 0.5

and molar mass of solute , $M_{solute}$ = molar mass of urea = 60g/mol

we know,

molality = $\frac{1000x_A}{M_{solute}x_B}$

= 1000 × 0.5/(60 × 0.5)

= 500/30

= 50/3 = 16.67m

hence, molality of the solution is 16.67m

Answer 2

Answer:

The molality of solution is 16.5

Explanation:

Molality=$\frac{Number of moles of solute}{Kg of asolvent}$

Given, mole fraction of urea and

                $CH_{3}COOH$ =0.5

Molecular weight of Urea = 60g/mol

Weight of$CH_{3}COOH$ = 0.06 *0.5

                                    =0.03kg

m(Molality) =0.5/0.03=50/3=16.5

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