What mass of glycerin should be taken before preparing an aqueous solution weighing 300 g

What mass of glycerin should be taken before preparing an aqueous solution weighing 300 g with a mass fraction of glycerin 20%?

Let us find the masses of the constituent components of the solution.

This requires multiplying their mass fraction by the weight of the solution.

Let’s calculate the weight of the dissolved glycerin.

M glycerin = 300 x 0.2 = 60 grams;

In the same way, we find the weight of the solvent (water).

(In the calculations, we take the density of water equal to 1 gram / cm3).

M water = 300 x 0.8 = 240 grams = 240 ml;

Let’s check. To do this, we sum up the masses of the components of the solution and obtain the mass of the required solution.

60 + 240 = 300;