An amount of 20 g of cooper (II) oxide was treated with a stoichiometr

1.	An amount of 20 g of cooper (II) oxide was treated with a stoichiometric amount of a warm 20% sulphuric acid solution to produce a solution of copper (II) sulphate. How many grams of crystalline copper(II) sulphate (CuSO4 . 5 H2O) have crystallised when the solution is cooled to 20 °C? Relative atomic masses: Ar(Cu) = 63.5; Ar(S) = 32; Ar(O) = 16; Ar(H) = 1 Solubility of CuSO4 at 20 oC: s = 20.9 g of CuSO4 in 100 g of H2O.
Answer» CuO + H₂SO₄ → CuSO₄ + H₂O n(CuO) = m(CuO)/M(CuO) = 20 g/79.5 g mol^-1 = 0.2516 g n(H₂SO₄) = n(CuSO₄) = 0.2516 mol Mass of the CuSO₄ solution obtained by the reaction: m(solution CuSO₄) = m(CuO) + m(solution H₂SO₄) = = m(CuO) + n(H₂SO₄) x M(H₂SO₄)/w(H₂SO₄) = 20 g + 0.2516 mol 98 g mo-1/ 0.20 m(solution CuSO₄) = 143.28 g Mass fraction of CuSO₄: (a) in the solution obtained: w(CuSO₄) = m(CuSO₄)/m(solution CuSO₄) = n(CuSO ) (CuSO )/(solution CuSO₄) = 028 (b) in saturated solution of CuSO₄ at 20°C: w(CuSO₄) = 209 g/120.9 g = 0.173 (c) in crystalline CuSO₄ . 5 H₂O: w(CuSO₄) = M(CuSO₄)/M (CuSO₄.5H₂O) =0.639 Mass balance equation for CuSO₄: 0.28 m = 0.639 m₁ + 0.173 m₂ m - mass of the CuSO₄ solution obtained by the reaction at a higher temperature. m₁ - mass of the crystalline CuSO₄ .5H₂O. m2 - mass of the saturated solution of CuSO₄ at 20 °C. 0.28 × 143.28 = 0.639 m₁ + 0.173 × (143.28 - m₁) m1 = 32.9 g The yield of the crystallisation is 32.9 g of CuSO₄ . 5H₂O.

An amount of 20 g of cooper (II) oxide was treated with a stoichiometric amount of a warm 20% sulphuric acid solution to produce a solution of copper (II) sulphate. How many grams of crystalline copper(II) sulphate (CuSO4 . 5 H2O) have crystallised when the solution is cooled to 20 °C? Relative atomic masses: Ar(Cu) = 63.5; Ar(S) = 32; Ar(O) = 16; Ar(H) = 1 Solubility of CuSO4 at 20 oC: s = 20.9 g of CuSO4 in 100 g of H2O.

Answer»

CuO + H₂SO₄ → CuSO₄ + H₂O

n(CuO) = m(CuO)/M(CuO) = 20 g/79.5 g mol^-1 = 0.2516 g

n(H₂SO₄) = n(CuSO₄) = 0.2516 mol

Mass of the CuSO₄ solution obtained by the reaction:

m(solution CuSO₄) = m(CuO) + m(solution H₂SO₄) =

= m(CuO) + n(H₂SO₄) x M(H₂SO₄)/w(H₂SO₄)

= 20 g + 0.2516 mol 98 g mo-1/ 0.20

m(solution CuSO₄) = 143.28 g

Mass fraction of CuSO₄:

(a) in the solution obtained:

w(CuSO₄) = m(CuSO₄)/m(solution CuSO₄)

= n(CuSO ) (CuSO )/(solution CuSO₄) = 028

(b) in saturated solution of CuSO₄ at 20°C:

w(CuSO₄) = 209 g/120.9 g = 0.173

w(CuSO₄) = M(CuSO₄)/M (CuSO₄.5H₂O) =0.639

Mass balance equation for CuSO₄:

0.28 m = 0.639 m₁ + 0.173 m₂

m - mass of the CuSO₄ solution obtained by the reaction at a higher temperature.

m₁ - mass of the crystalline CuSO₄ .5H₂O.

m2 - mass of the saturated solution of CuSO₄ at 20 °C.

0.28 × 143.28 = 0.639 m₁ + 0.173 × (143.28 - m₁)

m1 = 32.9 g

The yield of the crystallisation is 32.9 g of CuSO₄ . 5H₂O.