The mass fraction of iodine in the pharmacy tincture is 3%. How much iodine and alcohol do you need to take to prepare 15 g of tincture?

Given: ω (iodine) = 3%, or 0.03, m (tincture) = 15 g.
Find: m (iodine) – ?, m (alcohol) -?
Decision.
1. Let’s find the mass of iodine:
m (iodine) = m (solution a) • ω (iodine) = 15 g • 0.03 = 0.45 g.
2. Find the mass of the solvent (alcohol):
m (alcohol) = m (p-pa) – m (iodine) = 15 g – 0.45 g = 14.55 g.
Answer: m (iodine) = 0.45 g; m (alcohol) = 14.55 g.

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