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

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) -?

Solution:

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.