Answer to Question #173510 in General Chemistry for Anonymous

Question

Calculate the mass of the precipitate formed by mixing 20 g of an 8% solution of ferrous sulphate with a sufficient quantity of sodium hydroxide solution.

Answer 1

FeSO₄ + 2NaOH $\to$ Fe(OH)₂ + Na₂SO₄

1 mol of FeSO₄ give 1 mole of Fe(OH)₂

20 g of 8 %of ferrous sulphate

8 g of ferrous sulphate in 100 g

4 g of ferrous sulphate in 20 g

moles of ferrous sulphate = 4/151.908 = 0.026 mol

Mass of precipitate Fe(OH)₂ = 0.026×89.86

= 2.33g