To 100 g of a solution, the mass fraction of potassium hydroxide in which is 0.25

| September 26, 2021 | education

To 100 g of a solution, the mass fraction of potassium hydroxide in which is 0.25, added 40 g of water. what is the mass fraction of alkali in the resulting solution?

Formulas of substances participating in the reaction:
KOH.
H2O.
1) Find the mass of the potassium hydroxide solute. To do this, multiply the mass fraction of the substance by the mass of the solution: 100 * 0.25 = 25g.
2) In order to find the mass of the resulting solution, we must add the mass of the original solution and the mass of added water: 100 + 40 = 140g.
3) The mass of the solute will not change after adding water.
4) Find the mass fraction of the substance in the resulting solution. To do this, divide the mass of the solute by the mass of the resulting solution and multiply by one hundred percent: 25/140 * 100 = 17.9% – the answer.



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