Question 3B
(a) State what would be observed if aqueous ammonia is added in drops till it is in
excess to a sample of copper (II)chloride in a test tube.
[3 marks]
(b) Calculate the mass of sodium trioxocarbonate (IV) required to prepare 600 cm3 of 0.35 mol dm-3 solution. [C=12.0, O=16.0, Na = 23.0]
[3 marks]
Observation
Majority of the candidates responded to this question and their performance was above average.
In part (a), majority of the candidates stated what would be observed if aqueous ammonia is added in drops till it is in excess to a sample of copper(II) chloride solution in a test tube.
In part (b), majority of the candidates could not calculate the mass of sodium trioxocarbonate (IV) required to prepare 600 cm3 of 0.35 mol dm-3 solution.
The expected answers include:
