How many grams of solute are contained in 356 g of a 12.5% (w/w) solution?

44.5 g of solute are contained in 356g of a 12.5% (w/w) solution.

Explanation:

12.5% (w/w) is the mass/mass percentage concentration of the solution.

% (w/w) = (mass of solute/mass of solution) * 100

Subsititue with:

% (w/w) = 12.5 mass of solution 356g

And solve for the mass of solute:

12.5 = (mass of solute / 356g) * 100

mass of solute = 12.5 * 356g / 100 = 44.5 g ← answer