What mass of potassium hydroxide should be dissolved in 400 g of water so that the mass fraction becomes 20%

univerkov | January 17, 2021 | education

Given:
m (H2O) = 400 g
w2 (KOH) = 20% = 0.2
To find:
m in islands (KOH)
Decision:
Let m islands (KOH) = x
m solution (KOH) = 400 + x
m in-va 1 (KOH) = m in-va 2 (KOH)
x = (400 + x) * 0.2
x = 80 + 0.2x
0.8x = 80
x = 100
Answer: 100 g

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