Calculate the mass of the precipitate that forms when mixing 165 g of a solution with a mass fraction

Calculate the mass of the precipitate that forms when mixing 165 g of a solution with a mass fraction of sulfuric acid of 25% and a solution of lead nitrate (Pb (NO3) 2).

Given:

m (H2SO4) = 165 g

w% (H2SO4) = 25%

Find:

m (draft) -?

Solution:

H2SO4 + Pb (NO3) 2 = PbSO4 + 2HNO3, – we solve the problem, relying on the composed reaction equation:

1) Find the mass of sulfuric acid in the reacted solution:

m (H2SO4) = 165 g * 0.25 = 41.25 g

2) Find the amount of sulfuric acid:

n (H2SO4) = m: M = 41.25 g: 98 g / mol = 0.42 mol

3) We compose a logical expression:

If 1 mol of H2SO4 gives 1 mol of PbSO4,

then 0.42 mol H2SO4 will give x mol PbSO4,

then x = 0.42 mol.

4) Find the mass of precipitated lead sulfate:

m (PbSO4) = n * M = 0.42 mol * 303 g / mol = 127.26 g.

Answer: m (PbSO4) = 127.26 g.