Mixed 150 g of a solution of potassium nitrate with a mass fraction of 12% and 300 g of a solution of the same salt with a mass fraction of 7%.

Mixed 150 g of a solution of potassium nitrate with a mass fraction of 12% and 300 g of a solution of the same salt with a mass fraction of 7%. The mass fraction of salt in the resulting solution is equal to.

ω (X) = {m1 (p-p) ω1 + m2 (p-p) ω2} / {m1 (p-p) + m2 (p-p)}
ω = 150 * 0.12 + 300 * 0.07 / (150 + 300) = 18 + 21/450 = 0.087 or 8.7%

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