To 30 g of a solution containing 5% copper sulfate (2) was added 10% sodium hydroxide.

To 30 g of a solution containing 5% copper sulfate (2) was added 10% sodium hydroxide. Calculate the mass of the precipitate formed.

Given:

m (CuSO4) = 30 g

w% (CuSO4) = 5%

To find:

m (draft) -?

Decision:

CuSO4 + 2NaOH = Cu (OH) 2 + Na2SO4, – we solve the problem based on the composed reaction equation:

1) Find the mass of copper sulfate in solution:

m (CuSO4) = 30 g * 0.05 = 1.5 g

2) Find the amount of copper sulfate:

n (CuSO4) = m: M = 1.5 g: 160 g / mol = 0.009 mol

3) We compose a logical expression:

if 1 mol of CuSO4 gives 1 mol of Cu (OH) 2,

then 0.009 mol CuSO4 will give x mol Cu (OH) 2,

then x = 0.009 mol.

4) Find the mass of copper hydroxide precipitated as a result of the reaction:

m (Cu (OH) 2) = n * M = 0.009 mol * 98 g / mol = 0.882 g.

Answer: m (Cu (OH) 2) = 0.882 g.