Calculate the mass of the precipitate that forms when copper sulfate solution (2) is added

Calculate the mass of the precipitate that forms when copper sulfate solution (2) is added to a solution containing 4 g of sodium hydroxide.

Given:

m (NaOH) = 4 g

To find:

m (draft) -?

Decision:

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

1) Find the amount of sodium hydroxide in the solution:

n (NaOH) = m: M = 4 g: 40 g / mol = 0.1 mol

2) We compose a logical expression:

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

then 0.1 mol NaOH will give x mol Cu (OH) 2,

then x = 0.05 mol.

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

m (Cu (OH) 2) = n * M = 0.05 mol * 98 g / mol = 4.9 g.

Answer: m (Cu (OH) 2) = 4.9 g.