Question

Aqueous solution of urea is 20% by mass of solution then the percentage by mass of solvent is

Answer 1

Mass % of Urea = 20 %

Mass of Urea = 20g .

In 100 gm of solution , 20 g urea is present.

So, Mass of solvent = 100 - 20 gm

Mass of solvent ( Water ) = 80 gm

Mass % of solvent = Mass of solvent * 100 / Mass of solution

Mass % of solvent = 20 * 100 / 80

Mass % of solvent = 25 %.

Answer 2

Answer:

The percentage by mass of solvent is 25%.

Explanation:

Mass percentage of urea in aqueous solution = 20%

In 100 g of solution there is 20 g of urea and 80 g of water.

Mass of solute or urea = 20 g

Mass of solvent = 80 g

Percentage of urea by mass of solvent of

$\frac{\text{Mass of the solute}}{\text{Mass of the solvent}}\times 100$

$=\frac{20 g}{80 g}\times 100=25\%$

The percentage by mass of solvent is 25%.