Calculate the chemical amount of sodium hydroxide that will be required to prepare

Calculate the chemical amount of sodium hydroxide that will be required to prepare a solution weighing 80 grams with a mass fraction of alkali of 20%.

Let’s find the mass of water and alkali in the solution. To do this, we multiply their mass fractions by the mass of the solution.

M solution = 80 grams;

M alkali = 80 x 0.2 = 16 grams;

M water = 80 x 0.8 = 64 grams;

Find the amount of substance in 16 grams of sodium hydroxide.

M NaOH = 23 + 16 + 1 = 40 grams / mol;

The amount of substance will be:

N NaOH = 16/40 = 0.4 mol;