What mass of sodium nitrate must be dissolved in 200 grams of water to obtain a solution with a mass fraction of 20%?

univerkov | January 17, 2021 | education

Given:
m (H2O) = 200 g
w2 (NaNO3) = 20% = 0.2
To find:
m1 (NaNO3)
Decision:
Let m1 (NaNO3) – x g, then m2 solution (NaNO3) = 200 g + x g
w (NaNO₃) = m in-islands (NaNO₃) / m solution (NaNO3)
0.2 = x / 200 + x
x = 0.2 * (200 + x)
x = 40 + 0.2x
0.8x = 40
x = 50
Answer: 50 g

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