To 80 g of a solution with a mass fraction of calcium chloride of 25%, 10 g of the same salt was added. How many milliliters of water should be added to the resulting solution so that the mass fraction of salt is 15%?
1) Find the mass of the calcium chloride solute in its solution. To do this, we multiply the mass fraction of the substance by the mass of the entire solution and divide by one hundred percent: 25 * 80/100 = 20g.
2) Find the mass of the solute after adding salt: 20 + 10 = 30g.
3) Find the mass of the solution after adding salt: 80 + 10 = 90g.
4) Find the mass of the solution in a 15% solution. To do this, we multiply the mass of the solute by one hundred percent and divide by the mass fraction: 30 * 100/15 = 200g.
5) Find the mass of water: 200 – 90 = 110g.
110g = 110ml – Answer.
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