# Calculate the volumes of sulfuric acid (72%), the density of which is 1.64 g / cm3

**Calculate the volumes of sulfuric acid (72%), the density of which is 1.64 g / cm3, and water required to prepare 400 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 sulfuric acid.

M acid = 400 x 0.2 = 80 grams;

In order to find the volume of a sulfuric acid solution with such an acid weight, it is necessary to divide this acid weight by its concentration and density.

The volume of the sulfuric acid solution will be:

V sulfuric acid solution = 80 / 0.72 / 1.64 = 67.75 ml;

The weight of the water will be:

M water = 400 x 0.8 = 320 grams;

The sulfuric acid solution contains 28% water. Its mass is 80 / 0.72 – 80 = 31.11 grams.

Therefore, it is necessary to add less water, amounting to:

M water additive = 320 – 31.11 = 288.89 grams = 288.89 ml;

Let’s check:

M solution = M acid + M water (solvent) = 80 + 320 = 400 grams;