Question

Calculate the mass of sodium sulphate required to prepare a 20% (m/m%) solution in 100 g of water?

[2 Marks]
[Exemplar Question]
[Concentration of Solution]

Answer 1

Given:

Concentration (m/m%) of sodium sulphate solution = 20%
Mass of the solvent = 100 g

Solution:

Let the mass of solute (sodium sulphate) = X g

Mass by mass percentage = (Mass of solute/Mass of solution) x 100
[1 Mark]

$20=\frac{X}{X+100}\times 100$

$80X=2000$
$X=25$

Therefore, the mass of sodium sulphate required to prepare the solution = 25 g

[1 Mark]