CIE iGCSE Co-Ordinated Science C7.3 Preparation of salts Exam Style Questions Paper 2
Question
What is warmed with a salt to test for ammonium ions?
(A) aqueous barium chloride
(B) aqueous litmus
(C) aqueous silver nitrate
(D) aqueous sodium hydroxide
▶️Answer/Explanation
Ans : D
Question
Copper(II) sulfate is produced by reacting copper(II) oxide with dilute sulfuric acid.
The stages in the process to produce pure dry crystals are listed.
1 Leave to crystallise in a cool place.
2 Filter the reaction mixture.
3 Press the crystals between dry filter papers.
4 Add copper(II) oxide until it is in excess.
5 Heat the filtrate to concentrate it.
6 Heat the dilute sulfuric acid.
What is the correct order for these stages?
A 6 → 4 →2 → 5 → 3 → 1
B 6 → 4 → 1 → 2 → 5 → 3
C 6 → 4 → 2 → 5 →1 → 3
D 4 → 6 → 2 → 1 → 5 → 3
▶️Answer/Explanation
Ans : C
Question
Crystals of copper(II) sulfate, a soluble salt, are made by reacting excess copper(II) oxide with dilute sulfuric acid.
After filtering off the unreacted copper(II) oxide, the solution is heated until it is saturated. It is then left to cool.
Which statements about this preparation are correct?
1 Excess copper(II) oxide is used in order to ensure a high yield is obtained.
2 After filtering, the solution is heated to evaporate some of the water.
3 When the saturated solution cools, crystals of copper(II) sulfate begin to appear.
4 After cooling, the water is rapidly removed by evaporation.
A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4
▶️Answer/Explanation
Ans : C
Question
Copper carbonate is insoluble in water.
Which method can be used to make copper carbonate?
A adding aqueous sodium carbonate to aqueous copper sulfate and filtering off the product
B adding solid calcium carbonate to aqueous copper sulfate and filtering off the product
C adding solid copper oxide to solid calcium carbonate and heating the mixture
D heating copper metal in carbon dioxide
▶️Answer/Explanation
Ans :A