Question

the mole fraction of solute in aqueous urea solution is 0.2. Calculate the mass percent of solute

Answer 1

Mass apon to voluam =mass

Answer 2

Answer:

45.45 is the mass percent of the given solute.

Explanation:

Number of moles $=\frac{\text { mass }}{\text { molar mass }}$

Mole fraction of solute = 0.2  

Mole fraction of solvent = 1 - 0.2 = 0.8

Since the solution given is aqueous solute here will be urea and solvent will be water.

Urea’s Mole fraction $= \frac{n_{u r e a}}{\left(n_{u r e a}+n_{w a t e r}\right)}$

Molar mass of urea = 60 $\mathrm{g} \mathrm{mol}^{-1}$

Mass of urea = 0.2×60= 12 g

Mass % of solute  $=\frac{(\text {Mass of solute })}{\text {mass of solution}} \times 100$

$=\frac{12}{26.4} \times 100=45.45$