To 300 g of a 15% KOH solution was added 250 g of water. Determine the percentage of the resulting solution.

– Find the amount of potassium hydroxide substance in its solution. To do this, multiply the mass fraction by the mass of the solution and divide by one hundred percent:
15 * 300/100 = 45g.
– Next, we find the mass of the solution after adding water. Because water is added, not a hydroxide solution, then only the mass of the solution will change, without changing the mass of the solute.
Thus, the mass of the resulting solution is found by adding the initial mass of the solution and the mass of added water:
300 + 250 = 550g.
-Calculate the mass fraction of the substance in the resulting solution. To do this, divide the mass of the solute by the mass of the solution obtained by adding water and multiply by one hundred percent:
45/550 * 100 = 8.2% – the answer.

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