What mass of salt should be taken to prepare 200 g of a 15% solution?

Find the masses 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 = 200 x 0.15 = 30 grams;

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

(In the calculations, we will make the assumption that the density of water is 1 gram / ml).

M water = 200 x 0.85 = 170 grams;

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

170 + 30 = 200;