What mass of sodium oxide must be taken to prepare 500 g of sodium hydroxide solution

What mass of sodium oxide must be taken to prepare 500 g of sodium hydroxide solution with a mass fraction of 2.5%?

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 alkali.

M alkali = 500 x 0.025 = 12.5 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 = 500 x 0.975 = 487.5 grams;

Let’s check. To do this, add the masses of the components of the solution and get the mass of the required solution.

12.5 + 487.5 = 500;