In what mass of water should be dissolved 100 gr. AgNO3 to obtain a solution with a mass fraction of 40%?

The mass of silver nitrate is 100 g.

Mass fraction of the solution – 40%.

Let’s determine the mass of water.

To do this, you must first write down the formula.

W = m r.v / m r-ra * 100%.

Next, we denote the mass of water through x.

The mass of the solution is equal to the mass of water, add the mass of silver nitrate. Next, we write down an expression with one unknown.

40 = 100 / (x + 100) * 100.

40 = 10000 / (x + 100).

40 * (x + 100) = 10000.

40x + 4000 = 10000.

40x = 10000 – 4000.

40x = 6000.

X = 6000/40 = 150.

Therefore, in order to obtain a 40% solution, it is necessary to add 150 g of water.

Answer: the mass of water is 150 g.