How many grams of KOH should be added to 400 grams of a 2% solution to get a 4% solution.

univerkov | November 25, 2020 | education

Given
m = 400 g
w (KOH) = 2.5% = 0.025
Decision
w (KOH) = m (KOH) / (m + m (KOH)) = m (KOH) / (400 + m (KOH)) = 0.025
m (KOH) / (400 + m (KOH)) = 0.025
m (KOH) = 0.025 (400 + m (KOH))
m (KOH) = 0.025 (400 + m (KOH))
m (KOH) = 10 + 0.025m (KOH)
0.975m (KOH) = 10
m (KOH) = 10.26 g
Answer: 10.26 g

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