Two salt solutions were mixed: 120 g of a 5% solution and 130 g of a 15% solution.

Two salt solutions were mixed: 120 g of a 5% solution and 130 g of a 15% solution. Calculate the mass fraction of salt in the resulting solution.

Let’s find the mass of salt in the 1st solution:

m1 (salts) = mr.-pa1 (salts) * w1 (salts) / 100 = 120 * 5/100 = 6 (g).

Let’s find the mass of salt in the 2nd solution:

m2 (salts) = mr.-pa2 (salts) * w2 (salts) / 100 = 130 * 15/100 = 19.5 (g).

Find the mass of salt in the resulting solution:

m3 (salt) = m1 (salt) + m2 (salt) = 6 + 19.5 = 25.5 (g).

Let’s find the mass of the resulting solution:

mr.-pa3 (salts) = m.-pa1 (salts) + m.-pa2 (salts) = 120 + 130 = 250 (g).

Let’s find the mass fraction of salt in the resulting solution:

w3 (salt) = (m3 (salt) / mp-pa3 (salt)) * 100 = (25.5 / 250) * 100 = 10.2 (g).

Answer: 10.2 g.