To 500 g of a solution with a mass fraction of 5% salt was added 100 g of water.

To 500 g of a solution with a mass fraction of 5% salt was added 100 g of water. Calculate the mass fraction of salt in the resulting solution.

In order to solve this problem, we must calculate the mass of the solute. Next, we find the mass of the solution after adding water. And finally, we find the mass fraction of salt in the resulting solution.
1) W = (mr.v – wa / mr – pa) * 100%.
5 = (x / 500) * 100%.
x = 25g is the mass of the solute.
2) 500 + 100 = 600g – the mass of the solution after adding water.
3) Find the mass fraction of salt in the solution: W = (25/600) * 100% = 4.2% – the answer.