Find the mass of the precipitate that forms when 320 g of a 20% copper sulfate solution
Find the mass of the precipitate that forms when 320 g of a 20% copper sulfate solution (2) interacts with 56 g of a 10% potassium hydroxide solution.
1. Let’s write down the reaction equation:
CuSO4 + 2KOH = Cu (OH) 2 + K2SO4.
2. Find the amount of copper sulfate and potassium hydroxide:
m (CuSO4) = m (solution) * ω (CuSO4) / 100% = 320 g * 20% / 100% = 64 g.
n (CuSO4) = m (CuSO4) / M (CuSO4) = 64 g / 160 g / mol = 0.4 mol.
m (KOH) = m (solution) * ω (KOH) / 100% = 56 g * 10% / 100% = 5.6 g.
n (KOH) = m (KOH) / M (KOH) = 5.6 g / 56 g / mol = 0.1 mol.
3. According to the reaction equation, it can be seen that potassium hydroxide is in short supply, therefore, from it we find the amount of precipitate:
n (Cu (OH) 2) = n (KOH) / 2 = 0.1 mol / 2 = 0.05 mol.
m (Cu (OH) 2) = n (Cu (OH) 2) * M (Cu (OH) 2) = 0.05 mol * 98 g / mol = 4.9 g.
Answer: m (Cu (OH) 2) = 4.9 g.