Another 20 g of this substance was dissolved in a solution of potassium hydroxide with a mass of 160 g

| April 28, 2021 | education

Another 20 g of this substance was dissolved in a solution of potassium hydroxide with a mass of 160 g and a mass fraction of KOH equal to 10%. Determine the mamsa fraction of potassium hydroxide in the resulting solution.

Given:
m (KOH) solution = 160 g
w (KOH) r.h. = 10%
m2 (KOH) r.w. = 20 g
Define:
w2 (KOH) r.v. -?

Decision:
1. Find the mass of potassium hydroxide (solute) in the original solution
m (KOH) r.w. = 160g * 0.1 = 16g
2. Find the mass of water in the original solution
m (H2O) = 160 g -16 g = 144 g
3. Find the mass of potassium hydroxide in the solution after adding it m3 (KOH) r.v.
m3 (KOH) r.w. = 16 g + 20 g = 36 g
4. Find the mass of the resulting solution
m2 (KOH) solution = 144 g + 36 g = 180 g
5. Find the mass fraction of potassium hydroxide in the resulting solution
w2 (KOH) r.w. = 36g / 180g = 0.2 or 20%



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