Determine the mass of salt and water that are needed to prepare 250 grams of a 10% solution.

In order to determine the mass of salt and water that are needed to prepare 250 grams of a 10% solution, you need to use the formula: w = (mr.w: mr-ra) * 100.
mr.w is the mass of salt that you need to find out, mr-ra is the mass of the solution, 250 g, w is the mass fraction.
As a consequence: mr.v = (w * mr-ra) / 100%.
We substitute the known ones into the formula: mr.w = (10 * 250) / 100%, mr.w = 25 g (mass of salt)
mr-ra = mr.w + mwater;
mwater = mr-ra – mr.v;
mwater = 250 – 25 = 225 (g)
Answer: the mass of salt is 25 g, the mass of water is 225 g.