10-minute Quiz : Chapter 3 The ocean

A mixture of copper(II) chloride solution and copper is separated using the set-up shown in the diagram below. Which of the following statements concerning the process are correct?

(1) The process involves a physical change.

(2) The filtrate gives a bluish green flame in a flame test.

(3) The residue contains copper(II) chloride solid.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

A soup is made by heating different ingredients such as vegetables with water. Which of the following methods can be used to obtain water from the soup?

• A. Crystallization
• B. Filtration
• C. Distillation
• D. Precipitation

You are given a dilute table salt solution. Which of the following actions can increase the concentration of the table salt solution?

(1) Adding more water to the solution

(2) Heating the solution to remove some water

(3) Adding more table salt to the solution

• A. (1) only
• B. (2) only
• C. (1) and (3) only
• D. (2) and (3) only

Which of the following processes will show a colour change from blue to white?

• A. Heating hydrated cobalt(II) chloride crystals
• B. Heating hydrated copper(II) sulphate crystals
• C. Adding water to anhydrous cobalt(II) chloride
• D. Adding water to anhydrous copper(II) sulphate

A mixture of sulphur and iron powder needs to be separated. The solubilities of sulphur and iron powder in water and in carbon disulphide are shown in the following table. What are possible methods of separating the mixture of sulphur and iron powder?

• A
• B
• C
• D

A solid gives a lilac flame in a flame test. It shows a negative result in a silver nitrate test. The solid may be

• A. sodium nitrate.
• B. sodium chloride.
• C. potassium nitrate.
• D. potassium chloride.

A solid can be obtained by crystallization from its aqueous solution. Which of the following properties does the solid have?

• A. It dissolves in cold water but not in hot water.
• B. It is equally soluble in hot and cold water.
• C. It is more soluble in hot water than in cold water.
• D. It is very soluble in cold water.

Which of the following pieces of apparatus is NOT needed for isolating pure water from sea water?

• A
• B
• C
• D

Which of the following statements concerning hydrogen are correct?

(1) It is an element.

(2) It can be obtained by the electrolysis of sea water.

(3) It can be used as a rocket fuel.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

A liquid freezes at 0°C. Which of the following properties of the liquid proves that it is pure water?

• A. It does not leave any residue when heated to dryness.
• B. It boils sharply at 100°C.
• C. It is colourless.
• D. It is neutral.