Mole fraction of urea in its aqueous solution is 0.25 .What is the mass of urea present in 200 g urea solution ? (Molecular mass of urea is 60 g `mol^(-1)`)

Answer

Mass of urea present =33.33 g

Explanation

Given : Mole fraction of urea = 0.25
Mass of urea in 200 g solution = ?
Mole fraction of water = 1- 0.25 =0.75
Mass of urea = 0.25 `xx 60 =15 g`
Mass of water = 0.75 `xx 100 = 75 g`
`:.` Mass of solution = 15+ 75 = 90 g
`:.` 90 g solution contains 15 g urea
`:.200` g solution will contain `(200 xx 15)/(90) ` = 33.33 g urea