Question

Calculate the mass of sodium sulphate required to prepared its 20% (mas percent) solution in 100g of water​

Answer 1

mass % of sodium sulphate = 20%.

Let the mass of sodium sulphate which is required to prepare this solution be x grams.

mass of water = 100 g.

So,

Mass of the solution = mass of solute + mass of solvent

20 = [ x / ( x + 100 ] * 100

20 / 100 = [ x / x + 100 ]

1 / 5 = x / x + 100

x + 100 / 5 = x

x + 100 = 5x

5x - x = 100

4x = 100

x = 100 / 4

x = 25

25g of sodium sulphate is required.