# Determine the mass of potassium hydroxide, which must be dissolved in 0.6 l of water

Determine the mass of potassium hydroxide, which must be dissolved in 0.6 l of water to prepare a solution with a mass fraction of alkali of 0.2 ..

In this solution, 6 liters of water will have a mass fraction of 80%.

Determine the weight of the solution. To do this, we divide the weight of water by its mass fraction.

M solution = M water / C water = 6000 / 0.8 = 7500 grams;

Let’s calculate the weight of the alkali.

To do this, subtract the mass of water from the weight of the solution.

M alkali = M solution – M water (solvent) = 7500 – 6000 = 1500 grams;

Let’s check:

6000 + 1500 = 7500;

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