Calculate the mass of salt in 20 ml. A solution with a mass fraction of 15% and a density of 1.1 g / ml.

Answer: 3.3 g.
Explanation of the solution: in order to solve this problem, you first need to find the mass of the salt solution, for this you need to multiply the density of the salt by its volume, we get the following:
m (solution) = p * v = 1.1 * 20 = 22 g.
Next, we will use the formula:
w = m (solution) / m (solution), where w is the mass fraction of salt in the solution, m (solution) is the mass of the solute, m (solution) is the mass of the solution.
We substitute all the values in the formula and find the mass of the solute salt:
m (p-stuff) = w * m (p-ra) = 0.15 * 22 = 3.3 g.