To 200 g of a 5% solution of ammonium chloride, 15 g of the same salt and the same amount of water were added. What is the mass fraction of ammonium chloride in the resulting solution?
Find the mass of salt m = 200 * 0.05 + 15 = 25 g
Find the mass of the final solution m (solution) = 200 + 15 + 15 = 230 g
ω = m (substance) / m (solution) = 25 * 100/230 = 11%
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