To 250 grams of 18% LiCl solution, 6 grams of the same salt was added. what is the mass fraction of salt in the solution.

1) ω = m-substance / m-solution x 100%
2) in order to find the mass of a substance that is contained in 250 g of an 18% LiCl solution, we need 250×0.18 = 45g
(We got 0.18, because to find the mass of a substance, you need to multiply the mass of the solution by omega and divide by one hundred percent)
3) we substitute it into our formula, which is in answer point 1, since we added another 6 grams of the substance to the solution, then we add it to both the substance and the solution
ω = 45 + 6/250 + 6 = 0.1992 or 19.92%