How many grams of salt and water should be taken to prepare 250 g of a 20% solution?

Determine the weights of the components of the solution.

To do this, it is necessary to multiply their mass fraction by the weight of the solution.

Let’s calculate the weight of the dissolved salt.

M salt = 250 x 0.2 = 50 grams;

Similarly, we find the weight of the solvent (water).

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

M water = 250 x 0.8 = 200 grams = 200 ml;

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

200 + 50 = 250;