To 200 g of an aqueous solution of the substance, 20 g of the same substance was added and a 30% solution was obtained.

univerkov | December 13, 2020 | education

To 200 g of an aqueous solution of the substance, 20 g of the same substance was added and a 30% solution was obtained. What was the mass fraction of the substance in the initial solution?

Let there be x g of the substance in the solution. Then the mass fraction w = (x +20) / 220 = 0.3 => x = 46 g (there was a substance). w = x / 200 = 46/200 = 0.23 = 23%
Answer: 23%

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