5 g of NaOH is dissolved in 45 g of water. Calculate the concentration of the solution (in%).

The solution consists of two components: water weighing 45 grams and a substance weighing 5 grams.

The mass of the solution is equal to the sum of their masses:

m solution = 45 + 5 = 50 grams.

To find the mass fraction of salt, we divide the mass of the substance by the mass of the solution:

C = m substance / m solution = 5/50 = 0.1 = 10%;