Mixed 300 g of a solution with a mass fraction of a substance of 25% and 400 g of a solution with a mass fraction of 40%.

Mixed 300 g of a solution with a mass fraction of a substance of 25% and 400 g of a solution with a mass fraction of 40%. Determine the mass fraction of the substance in the dissolved one.

Find the total mass of the solute:

m (solute) = 300 * 0.25 + 400 * 0.4 = 235 g;

The mass of the new solution:

m (solution) = 300 + 400 = 700 g;

Mass fraction of a solute in a new solution:

w (solute) = m (solute) / m (solution) = 235/700 = 0.3357 = 33.57%

Answer: w (solute) = 33.57%