1

Question Bank Topic 1Planet Earth

Class:___________Class No:__________Name:____________________ Mark:__________

Date:______________

Multiple choice question

Unit 1

1.3: Laboratory safety

1.4: Hazard warning labels

(CDC guide: Hazard warning labels and safety in laboratory)

1 Which of the following hazard warning labels should be displayed on a bottle of chlorine?

A B

CORROSIVE FLAMMABLE

C D

2 Which of the following hazard warning labels should be displayed on a bottle containing liquefied petroleum gas?

A B

C D

FLAMMABLE IRR ITANT

3 What is the meaning of the following hazard warning label?

IRR ITANT

A Toxic

B Carcinogenic

C Corrosive

D Harmful

4 Which of the following should NOT be done in laboratory?

A Wash hands after experiments

B Keep flammable chemicals away from naked flame

C Close all windows when doing experiments

D Turn off the Bunsen burner when it is not in use

1.5: Common apparatus in the laboratory

(CDC guide: Common apparatus in the laboratory)

1 Consider the experimental set-up below:

Which of the following combinations concerning apparatus X and Y is correct?

X Y

A Evaporating dish Rack

B Petri dish Tripod

C Petri dish Rack

D Evaporating dish Tripod

2 Consider the experimental set-up below:

Which of the following combinations concerning apparatus X, Y and Z is correct?

X Y Z

A Glass rod Stand Funnel

B Thermometer Stand Petri dish

C Glass rod Tripod Funnel

D Thermometer Tripod Petri dish

3 Which of the following apparatus are used to filter off insoluble solids from a solution?

(1) Crucible

(2) Funnel

(3) Beaker

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

4 Which of the following apparatus is/are NOT used to measure the volume of a solution?

(1) Wash bottle

(2) Measuring cylinder

(3) Dropper

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

Unit 2

2.2: Classification of matter: pure substance and mixture

2.3: Elements and compounds

(CDC guide: Classification of matter & Elements and compounds)

1 Which of the following statements is correct?

A There are thousands of elements on Earth.

B Compounds can join together chemically to form elements.

C Elements cannot be broken down into anything simpler by chemical methods.

D Water is an element.

2 Which of the following statements concerning compound is INCORRECT?

A Carbon dioxide is a compound.

B All compounds are naturally made.

C Compounds have different chemical properties from their constituent elements.

D Compounds cannot be separated into anything simpler by physical methods.

3 Which of the following comparisons between carbon dioxide and a mixture of carbon and oxygen is INCORRECT?

Carbon dioxide A mixture of carbon and oxygen

A Colourless gas A mixture of black solid and colourless gas

B Odourless Odourless

C Fixed composition Variable composition

D Supports combustion Does not support combustion

4 Which of the following comparisons between water and a mixture of hydrogen and oxygen is/ are correct?

Water A mixture of hydrogen and oxygen

(1) Extinguishes a burning splint Give a 'pop' sound with a burning splint

(2) Colourless Colourless

(3) A liquid at room temperature and pressure A gas at room temperature and pressure

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

5 Which of the following statements are correct?

(1) Compounds have different properties from their constituent elements.

(2 Compounds have variable composition.

(3) Common salt is a compound.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

6 Which of the following substances is/are compound(s)?

(1) Oxygen

(2) Water

(3) Ammonia

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

7 Which of the following substances is/are element(s)?

(1) Carbon

(2) Chlorine

(3) Dry ice

A (2) only

B (3) only

C (1) and (2) only

D (1) and (3) only

8 Which of the following elements are present in sugar?

(1) Carbon

(2) Nitrogen

(3) Hydrogen

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

2.4: The atmosphere

(CDC guide: Composition of air)

1 Which of the following gas(es) is/ are least likely to be found in air?

A Nitrogen

B Noble gases

C Hydrogen

D Carbon dioxide

2 Which of the following gases takes the greatest percentage of air by volume?

A Oxygen

B Nitrogen

C Carbon dioxide

D Noble gases

3 Which of the following combinations is INCORRECT?

Gas in air Composition

A Oxygen 21%

B Nitrogen 78%

C Carbon dioxide 0.4%

D Noble gases 0.9%

4 Which of the following statements is/are correct?

(1) Air is a compound.

(2) Carbon dioxide takes about 4% of air by volume.

(3) Air contains small amount of dusts and harmful gases.

A (2) only

B (3) only

C (1) and (2) only

D (1) and (3) only

5 Which of the following gases in air are elements?

(1) Nitrogen

(2) Noble gases

(3) Carbon dioxide

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

2:6: Separating oxygen and nitrogen from the air

(CDC guide: Separation of oxygen and nitrogen from liquid air by fractional distillation)

1 Which of the following substances is/ are least likely to be obtained from fractional distillation of liquid air?

A Nitrogen

B Oxygen

C Hydrogen

D Noble gases

2 Which of the following statements concerning fractional distillation of liquid air is correct?

A Air is cooled to 0℃.

B Oxygen boils at -183℃.

C Nitrogen gas is collected at lower part of the fractionating column.

D Noble gases cannot be separated from air in fractionating column.

3 Why can gases in air be separated by fractional distillation of liquid air?

A The gases have different boiling points.

B The gases have different melting points.

C The gases have different percentages in air by volume.

D The gases have different chemical properties.

Directions: Questions 4-5 refer to the diagram showing fractional distillation of liquid air to obtain oxygen and nitrogen.

4 Which of the following combinations concerning the functions of columns X and Y is correct?

Column X Column Y

A To liquefy air To purify air

B To purify air To liquefy air

C To purify air To remove noble gases

D To remove noble gases To liquefy air

5 Which of the following combinations concerning gases A and B are correct?

(1) Gas A takes the greatest percentage of air by volume.

(2) Gas B can relight a glowing splint.

(3) Gas B is a compound.

A (2) only

B (3) only

C (1) and (2) only

D (1) and (3) only

6 Arrange the order of the procedures of separation of oxygen and nitrogen from air.

(1) Liquefaction of air

(2) Fractional distillation of air

(3) Purification of air

A (1) → (2) → (3)

B (3) → (1) → (2)

C (3) → (2) → (1)

D (2) → (1) → (3)

7 Which of the following statements concerning fractional distillation of liquid air is/ are correct?

(1) Oxygen is obtained at lower temperature than nitrogen.

(2) Air should be purified before it is cooled to liquid.

(3) Noble gases can be obtained from fractional distillation of liquid air.

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

8 Which of the following substances can be obtained from fractional distillation of liquid air?

(1) Chlorine

(2) Oxygen

(3) Nitrogen

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

2.7: Physical and chemical properties

(CDC guide: Physical and Chemical Properties)

1 Which of the following is NOT a physical property of carbon?

A It is black in colour.

B It is a solid at room temperature.

C It is denser than water.

D It can be burnt in air.

2 Which of the following is NOT a physical property of carbon dioxide?

A Carbon dioxide is a gas at room temperature.

B Carbon dioxide has no smell.

C Carbon dioxide dissolves in water to give an acidic solution.

D Carbon dioxide has a higher density than oxygen.

3 Which of the following is/are chemical property(ies) of water?

(1) Water boils at 100℃ at room temperature and pressure.

(2) Hydrogen and oxygen are produced by the electrolysis of water.

(3) Ice melts at room temperature and pressure.

A (2) only

B (3) only

C (1) and (2) only

D (1) and (3) only

4

Substance Melting point ( ℃ ) Boiling point ( ℃ )

W -200 54

X 10 120

Y 50 320

Z -100 13

Which of the above substances is a liquid at room temperature?

A X only

B Y only

C W and X only

D Y and Z only

2.8: Test for oxygen

(CDC guide: Test for oxygen)

1 Which of the following statements concerning oxygen is INCORRECT?

A Oxygen relights a glowing splint.

B Oxygen is a constituent element of water.

C Oxygen is an element.

D Air contains 78% of oxygen.

2 Which of the following shows the presence of oxygen in a jar?

A It gives a 'pop' sound with a burning splint.

B It turns limewater milky.

C It relights a glowing splint.

D It extinguishes a burning splint.

3 Which of the following statements concerning oxygen is/are correct?

(1) Oxygen is flammable.

(2) Oxygen supports combustion.

(3) Oxygen relights a glowing splint.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

Unit 3

3.1: Sea water : a vast solution

3.6: Composition of sea water

(CDC guide: Composition of sea water)

1 Which of the following substances is the most abundant in sea water?

A Sodium chloride

B Oxygen

C Minerals

D Water

2 Which of the following substances are present in sea water?

(1) Sodium chloride

(2) Dissolved gases

(3) Minerals

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

3 Which of the following statements concerning sea water is/are correct?

(1) Sodium chloride is a solvent.

(2) Water is a solute.

(3) Sea water is a solution.

A (1) only

B (3) only

C (1) and (2) only

D (2) and (3) only

3.2: Obtaining common salt from sea water

3.3: Obtaining pure water from sea water

(CDC guide: Extraction of common salt and isolation of pure water from sea water)

1 Which of the following statements is INCORRECT?

A Sea water is a compound containing sodium chloride.

B Pure water can be obtained from distillation of sea water.

C Sodium chloride is soluble in water.

D Mud can be removed from sea water by filtration.

2 Consider the experimental set-up below:

Which of the following combinations concerning the functions of X and Y is correct?

X Y

A To speed up distillation To condense vapour

B To ensure even boiling To condense vapour

C To speed up distillation To remove impurities

D To ensure even boiling To remove impurities

3 Which of the following methods can remove insoluble solids in water?

A Crystallization

B Filtration

C Distillation

D Evaporation

4 Which of the following statements concerning evaporation of sea water is INCORRECT?

A Evaporation is a heat absorbing process.

B Water is removed from sea water during evaporation.

C Pure sodium chloride will be obtained.

D Powdery solid remained after evaporation.

5 Which of the following methods can be used to obtain pure water from a sample of sea water?

A Filtration

B Sublimation

C Crystallizaion

D Distillation

6 Which of the following statements concerning distillation of sea water using 'Quickfit' apparatus is/are correct?

(1) Anti-bumping granules are added into sea water to remove impurities.

(2) The bulb of the thermometer should be placed near to the opening of the side-arm.

(3) Cold water should be entered into the condenser at the upper end and leave at the lower end.

A (2) only

B (3) only

C (1) and (2) only

D (1) and (3) only

7 Which of the following processes can be used to obtain soluble substances from a solution?

(1) Filtration

(2) Crystallization

(3) Evaporation

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

8 Which of the following processes can be used to obtain large sodium chloride crystals from a sample of sea water?

(1) Crystallization

(2) Distillation

(3) Evaporation

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

9 Which of the following methods can be used to obtain copper(II) sulphate solids from copper(II) sulphate solution?

(1) Crystallization

(2) Filtration

(3) Evaporation

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

10 Which of the following apparatus can be used to filter off mud from a sample of sea water?

(1) Filter paper

(2) Funnel

(3) Beaker

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

11 Which of the following apparatus is/are NOT used in distillation of sea water?

(1) Filter paper

(2) Evaporating dish

(3) Thermometer

A (2) only

B (3) only

C (1) and (2) only

D (1) and (3) only

3.4: What does common salt contain?

(CDC guide: Tests to show the presence of sodium and chloride in a sample of common salt)

1 What colour can be observed when a sample of sodium chloride solid is heated in a Bunsen flame?

A Purple

B Red

C Green

D Golden yellow

2 What would be observed if sodium chloride is added to a solution containing dilute nitric acid and silver nitrate solution?

A Effervescence occurs.

B There is no observable change.

C The solution becomes blue in colour.

D White precipitate forms.

3 Which of the following is not an essential step of flame test?

A Dip a clean nichrome wire into concentrated hydrochloric acid.

B Dip the nichrome wire into water.

C Dip the nichrome wire into powdered sample.

D Heat the nichrome wire in a Bunsen flame.

4 Which of the following combinations concerning flame test is/are correct?

Compound Flame colour

(1) Potassium chloride Green

(2) Sodium chloride Golden yellow

(3 Calcium chloride Blue

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

5 Which of the following tests can be used to show the presence of sodium chloride in the solids obtained from evaporation of sea water?

(1) Flame test

(2) Dissolves the solids in water. Then add excess dilute nitric acid, followed by sliver nitrate solution

(3) Place a cobalt(II) chloride paper onto the solid

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

6 Which of the following reagents are used to test for the presence of chloride in a solution?

(1) Dilute nitric acid

(2) Dilute sodium hydroxide

(3) Silver nitrate solution

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

7 When dilute nitric acid and silver nitrate solution are added to a beaker containing an unknown solution, white precipitate forms. The unknown solution would possibly be

(1) sodium nitrate solution.

(2) potassium chloride solution.

(3) sea water.

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

8 Which of the following statements are correct?

(1) Silver nitrate solution is used to test for the presence of chloride in a solution.

(2) Sodium carbonate gives a golden yellow flame in flame test.

(3) Sodium chloride is soluble in water.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

3.5: Test for the presence of water in a sample

(CDC guide: Test for the presence of water in a sample)

1 When a dry cobalt(II) chloride paper is placed on a sample of moist sodium chloride, what will be observed?

A The dry cobalt(II) chloride paper turns pink.

B The dry cobalt(II) chloride paper turns blue.

C Effervescence occurs.

D There is no observable change.

2 Which of the following statements concerning copper(II) sulphate is INCORRECT?

A Copper(II) sulphate is a compound.

B Hydrated copper(II) sulphate is blue.

C Anhydrous copper(II) sulphate is pink.

D Copper(II) sulphate is soluble in water.

3 Which of the following can be used to test for the presence of water in a sample?

(1) Dry cobalt(II) chloride paper

(2) Anhydrous sodium chloride

(3 Acidified silver nitrate solution

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

4 Which of the following statements concerning water are correct?

(1) Water is a compound.

(2) Water turns dry cobalt(II) chloride paper pink.

(3) Water turns anhydrous copper(II) sulphate blue.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

3.7: Getting useful substances from sea water

3.8: The salt industry

(CDC guide: Electrolysis of sea water and uses of the products)

1 Which of the following substances will NOT be obtained in the electrolysis of sea water?

A Oxygen

B Hydrogen

C Chlorine

D Sodium hydroxide

2 Which of the following statements concerning electrolysis of sea water is correct?

A It involves a chemical change.

B It produces oxygen.

C It gives pure sodium chloride.

D It gives elements only.

3 Which of the following is NOT a major use of hydrogen?

A As a fuel

B Manufacture of ammonia

C Manufacture of hydrochloric acid

D Manufacture of plastics

4 Which of the following combinations concerning the products liberated in electrolysis of sea water is correct?

Positive electrode Negative electrode

A Hydrogen Chlorine

B Oxygen Chlorine

C Chlorine Hydrogen

D Chlorine Oxygen

5 After the electrolysis of sea water, the sea water in the container will become

A sodium chloride solution.

B pure water.

C sodium hydroxide solution.

D hydrochloric acid.

6 Which of the following substances can be obtained from electrolysis of sea water?

(1) Hydrogen

(2) Chlorine

(3) Sodium chloride

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

7 Which of the following are major uses of chlorine?

(1) Sterilizing swimming pool water

(2) Manufacture of soap

(3) Manufacture of hydrochloric acid

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

8 Which of the following is/are major use(s) of sodium hydroxide?

(1) Manufacture of bleach solution

(2 As a fuel

(3) Manufacture of soap

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

3.9: Physical and chemical changes

(CDC guide: Physical and Chemical changes)

1 Which of the following involves a chemical change?

A Passing electricity through a copper wire

B Dissolving sugar in water

C Burning a match

D Melting an iron object

2 Which of the following involve(s) a chemical change?

(1) Heating water

(2) Sublimation of iodine

(3) Burning charcoal

A (2) only

B (3) only

C (1) and (3) only

D (2) and (3) only

3 Which of the following statements are INCORRECT?

(1) Distillation of sea water involves a chemical change.

(2) Burning of wax involves chemical change only.

(3) When a compound undergoes a physical change, it can be broken down into its constituent elements.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

Unit 4

4.1: Metals in the Earth's crust

(CDC guide: Rocks as a source of minerals)

1 Which of the following metals can be extracted from bauxite?

A Aluminium

B Copper

C Lead

D Iron

2 Which of the following statements concerning rocks is/are correct?

(1) Haematite is a rock containing copper.

(2) The individual chemical compounds that make up rocks are minerals.

(3) Rocks from which metals are obtained are ores.

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

4.2: Extracting metals from their ores

(CDC guide: Isolation of useful materials from minerals as exemplified by extraction of metals from their ores)

1 Which of the following methods CANNOT be used to extract metals from their ores?

A Crystallization of molten ore

B Heating the ore with carbon

C Electrolysis of molten ore

D Heating the ore alone

2 Arrange the order of procedures of extraction of a metal from its ore.

(1) Extraction of the metals from minerals

(2) Mining of the ores

(3) Separation of useful minerals from waste materials

(4) Purification of impure metals

A (2) → (3) → (4) → (1)

B (2) → (4) → (3) → (1)

C (3) → (1) → (2) → (4)

D (2) → (3) → (1) → (4)

3 Which of the following methods are used to extract metals from their ores?

(1) Physical separation

(2) Electrolysis of molten ore

(3) Heating the ore with carbon

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

4 Which of the following combinations concerning extraction of metals from their ores is/are correct?

Metal to be extracted Method of extraction

(1) Aluminium Electrolysis of molten ore

(2) Copper Physical separation

(3) Lead Heating the ore alone

A (1) only

B (3) only

C (1) and (2) only

D (2) and (3) only

4.3: Investigating calcium carbonate

(CDC guide: Thermal decomposition of calcium carbonate and test for carbon dioxide)

1 When marble is heated, a gas is evolved. Which of the following statements concerning the gas evolved is correct?

A The gas is yellow in colour.

B The gas relights a glowing splint.

C The gas turns limewater milky.

D The gas is toxic.

2 When calcium carbonate is heated, a solid is obtained. Which of the following statements concerning the solid is correct?

A The solid is insoluble in water.

B The solid reacts with water to give slaked lime.

C The solid is calcium hydroxide.

D The solid is a mixture.

3 Which of the following statements concerning limewater is INCORRECT?

A Limewater is a colourless solution.

B Limewater is formed by dissolving calcium carbonate in excess water.

C Limewater is an aqueous solution of calcium hydroxide.

D Limewater becomes milky and then colourless when excess carbon dioxide is bubbled into it.

4 When carbon dioxide is bubbled into limewater, the solution becomes milky. It is due to the formation of

A calcium oxide.

B calcium hydroxide.

C calcium chloride.

D calcium carbonate.

5 Which of the following can be used to test the presence of carbon dioxide?

A Calcium carbonate solution

B Calcium hydroxide solution

C Calcium chloride solution

D Calcium sulphate solution

6 Which of the following would be produced when calcium carbonate is heated?

(1) Carbon dioxide

(2) Calcium oxide

(3) Calcium hydroxide

A (1) only

B (3) only

C (1) and (2) only

D (2) and (3) only

7 Which of the following methods can be used to produce limewater?

(1) Dissolve calcium carbonate in excess water

(2) Dissolve quicklime in excess water

(3) Heat a marble and dissolve the solid formed in excess water

A (1) only

B (3) only

C (1) and (2) only

D (2) and (3) only

(CDC guide: Tests to show the presence of calcium and carbonate in a sample of limestone/ chalk/ marble)

1 When a marble is heated in a Bunsen flame, which of the following flame colours would be observed?

A Golden yellow

B Brick-red

C Green

D Purple

2 When calcium carbonate is added into dilute hydrochloric acid, a gas is evolved. Which of the following concerning the gas is correct?

A The gas is explosive.

B The gas gives a 'pop' sound with a burning splint.

C The gas relights a glowing splint.

D The gas turns limewater milky.

3 To identify an unknown powder, a student heated the powder in a Bunsen flame. A brick-red flame was observed. When the student put the powder in dilute hydrochloric acid, it dissolves without any observable changes. What might the solid be?

A Calcium carbonate

B Sodium carbonate

C Calcium chloride

D Sodium chloride

Directions: Questions 4 and 5 refer to the diagram below.

4 What should gas X and solid Y be?

X Y

A Carbon dioxide Calcium carbonate

B Oxygen Calcium carbonate

C Carbon dioxide Calcium oxide

D Hydrogen Calcium oxide

5 What would be observed if excess gas X is introduced into limewater?

A Effervescence occurs.

B Solid Y dissolves.

C The solution becomes yellow in colour.

D There is no observable change.

6 When calcium carbonate is dissolved in dilute hydrochloric acid, which of the following substances would be formed?

(1) Calcium hydroxide

(2) Carbon dioxide

(3) Water

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

7 What would be observed when a piece of limestone is added into dilute hydrochloric acid?

(1) Gas bubbles evolves.

(2) Limestone dissolves.

(3) The solution turns milky.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

8 Which of the following statements concerning the products formed from heating limestone are true?

(1) The gas evolved turns limewater milky.

(2) The solid formed gives a brick-red flame in flame test.

(3) The solid formed is insoluble in water.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

9 A gas is evolved when a marble is added into dilute hydrochloric acid. Which of the following statements concerning the gas are correct?

(1) The gas turns limewater milky.

(2) The gas extinguishes a fire.

(3) The gas dissolves in water to form an acidic solution.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

10 Which of the following tests can be used to show the presence of calcium carbonate in chalk?

(1) Flame test

(2) Addition of chalk into dilute nitric acid, followed by silver nitrate solution

(3) Addition of chalk into dilute hydrochloric acid and test the gas evolved with limewater

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

11 Which of the following statements concerning limestone is/are INCORRECT?

(1) Limestone is soluble in water.

(2) Limestone is soluble in dilute hydrochloric acid.

(3) Limestone decomposes on heating.

A (1) only

B (2) only

C (1) and (3) only

D (2) and (3) only

4.4: Formation of chalk, limestone and marble

(CDC guide: Limestone, chalk and marble as different forms of calcium carbonate)

1 Which of the following statements concerning calcium carbonate is INCORRECT?

A Limestone, chalk and marble are different forms of calcium carbonate.

B Marble is the cheapest among different forms of calcium carbonate.

C Chalk is originated from remains of sea animals with shells.

D Calcium carbonate contains calcium, carbon and oxygen.

2 Which of the following combinations concerning the hardness of different forms of calcium carbonate is correct?

Softest Hardest

A Chalk Limestone

B Limestone Marble

C Chalk Marble

D Limestone Chalk

3 Which of the following statements concerning chalk is correct?

A Chalk is originates from remains of plants.

B Chalk is used to manufacture plastics.

C Chalk is softer than marble.

D Chalk is an element.

4 Which of the following are uses of limestone?

(1) Manufacture of cement

(2) Manufacture of glass

(3) Manufacture of soap

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

5 Which of the following statements concerning marble is/are INCORRECT?

(1) Marble is formed from limestone under high temperature and pressure.

(2) Marble is soluble in water.

(3) Marble has low melting point.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

4.5: Formation of limestone caves

(CDC guide: Erosion processes as exemplified by the action of heat, water and acids on calcium carbonate)

1 Which of the following can erode limestone?

(1) Wind

(2) Running water

(3) Heat

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

2 Which of the following explain(s) why rainwater can erode limestone?

(1) Limestone is soluble in water.

(2) Carbon dioxide in air dissolves in rainwater to form carbonic acid which dissolves limestone.

(3) Limestone reacts with water to form soluble calcium hydroxide.

A (2) only

B (3) only

C (1) and (2) only

D (1) and (3) only

Assertion-reason question

Directions: Please refer to the following instructions:

A Both statements are true and the 2nd statement is a correct explanation of the 1st statement.

B Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.

C The 1st statement is false while the 2nd statement is true.D Both statements are false.

1st statement 2nd statement

1 We should not place a bottle of alcohol near naked flames.

Alcohol is flammable.

2 The windows of the laboratory should be closed when doing experiments.

Windows are closed so that no toxic chemicals will escape from the laboratory.

3 We should display a hazard warning label 'flammable' on a jar containing oxygen.

Oxygen catches fire easily.

4 Oxygen is a compound. Oxygen cannot be broken down into anything simpler by physical methods.

5 Hydrogen is an element. Hydrogen can react with other substances to form new compounds.

6 Water is an element. Water can be broken down into anything simpler by chemical methods.

7 Solubility is a physical property. Sodium chloride is soluble in water.

8 Electrical conductivity is a chemical property.

Upon electrical conduction, copper is changed to new substances.

9 Rusting involves a chemical change. New substance is formed in the rusting process.

10 Heating water involves a chemical change.

Heating water produces vapour.

11 Burning wax does not produce new substances.

Burning wax involves both physical and chemical changes.

12 Air is a compound. Air consists of carbon dioxide.

13 Air is a mixture of elements only. Only nitrogen, oxygen and noble gases exist in air.

14 Nitrogen boils before oxygen in fractional distillation of liquid air.

Nitrogen takes greater percentage of air by volume than oxygen.

15 Nitrogen and oxygen can be separated by fractional distillation of liquid air.

Nitrogen and oxygen have different melting points.

16 Different gases can be obtained by fractional distillation of liquid air.

The gases in air have different boiling points.

17 Oxygen gives a 'pop' sound with a burning splint.

Oxygen supports combustion.

18 Pure water can be obtained from filtration of sea water.

Filtration removes insoluble substances from sea water.

19 Pure sodium chloride can be obtained from evaporation of sea water.

Evaporation removes water and all impurities from sea water.

20 Pure sodium chloride can be obtained from distillation of sea water.

Distillation removes all impurities from sea water.

21 Sodium chloride crystals obtained in crystallization should be washed with large amount of cold water.

Washing sodium chloride crystals with cold water can remove impurities on the surface of the crystals.

22 Common salt gives golden yellow flame in flame test.

Common salt contains sodium.

23 Nichrome wire should be washed with distilled water after dipping in concentrated hydrochloric acid in flame test.

Nichrome wire should be cleaned before it is used for flame test.

24 White precipitate is formed when solution of common salt is added to dilute nitric acid, followed by silver nitrate solution.

Common salt contains sodium.

25 Sea water is a compound. Chlorine and hydrogen are produced in electrolysis of sea water.

26 Aluminium can be extracted by heating bauxite alone.

Bauxite contains aluminium.

27 Limestone does not react with water. Limestone is insoluble in water.

28 When calcium carbonate is added into acid, the gas evolved gives a 'pop' sound with a burning splint.

The gas evolved is hydrogen.

29 Calcium carbonate is soluble in dilute hydrochloric acid.

Calcium carbonate reacts with dilute hydrochloric acid to form soluble calcium chloride.

30 Carbon dioxide turns limewater milky. Carbon dioxide reacts with limewater to form calcium carbonate.

31 Chalk gives a golden yellow flame in flame test.

Chalk contains calcium.

32 If a beaker containing limewater is left for several days, the limewater turns milky.

Air contains water vapour.

33 Limewater should be stored in closed bottles.

Limewater reacts with carbon dioxide in air to form calcium carbonate.

34 Limestone cannot be eroded by heat. There is no reaction when limestone is heated.

35 Rainwater erodes limestone. Rainwater contains dissolved oxygen.

Structured question

1. Air consists of oxygen and other substances.

(a) Is oxygen an element or a compound? Explain briefly.

(b) (i) What is the most abundant element in air?

(ii) What is the most abundant compound in air?

(c) Both oxygen and the element in (b)(i) can be obtained by fractional distillation of liquid air.

(i) Where does fractional distillation of liquid air take place in industry?

(ii) Explain briefly why oxygen and the element in (b)(i) can be obtained by fractional distillation of liquid air.

(iii) Does fractional distillation of liquid air involve physical or chemical change? Explain briefly.

(d) Suggest a test which allows you to distinguish between oxygen and the element in (b)(i).

(e) Suggest a test to identify the compound in (b)(ii).

(f) State the hazard warning label that should be displayed on a jar containing oxygen.

(13 marks)

2. Consider the following substances:

Sodium chloride, water, nitrogen, carbon dioxide, oxygen, argon

(a) Classify the above substances into elements and compounds.

(b) (i) Which of the above substances can be obtained from air industrially?

(ii) Give the name of the industrial method.

(c) Suggest chemical test(s) for

(i) oxygen;

(ii) sodium chloride; and

(iii) water.

(14 marks)

3. Some ice cream and ice cubes were taken out from a freezer at the same time and allowed to stand in air. The temperature was recorded respectively every minute until both had completely melted. The results are given in the table.

Time/minute Temperature of ice cream/℃ Temperature of ice/℃

0 -12 -121 -10 -6

2 -8 -3

3 -7 -1

4 -6 0

5 -5.5 06 -5 0

7 -4.5 0

8 -4 0

9 -3.5 0

10 -3 0

11 -2.5 0

12 -2 0

13 -1 0

14 0 0

15 2 0

16 4 1

17 6 4

(a) Draw curves for both sets of results on the same graph.

(b) According to the graph, determine

(i) the period of time in which the ice was melting; and

(ii) the time when both ice cubes and ice cream were completely melted.

(c) Is ice cream a mixture or a compound?

(d) Ice is the solid state of water.

(i) Suggest an experiment which can prove that water is a compound.

(ii) Suggest a test to show the presence of water in ice.

(9 marks)

4. The following is a sample of sea water collected by a student from a beach.

(a) Explain whether the sample is a mixture, an element or a compound.

(b) (i) Suggest how sand and mud can be removed from the sample.

(ii) Draw the experimental set-up for the separation in (b)(i).

(c) (i) State how sodium chloride powder can be obtained from the sample of sea water.

(ii) Draw the experimental set-up for (c)(i).

(iii) Describe how we can show the presence of chloride in the sodium chloride powder obtained.

(iv) Suggest a daily use of sodium chloride.

(13 marks)

5. Consider the following flowchart.

(a) (i) Suggest the physical process shown above.

(ii) What might solid X be?

(iii) Suggest a use of solid X.

(iv) Name the physical process in which pure solid X can be obtained from sea water.

(b) (i) Suggest the chemical process shown above.

(ii) Draw a labelled diagram of the experimental set-up for the above chemical process in the laboratory.

(c) (i) Suggest what gas Y might be.

(ii) State one common use of chlorine gas and gas Y respectively.

(11 marks)

6. A colourless solid melts at 0℃ and becomes a liquid at room temperature and pressure. When the liquid undergoes electrolysis, two colourless gases are formed.

(a) Identify the physical and chemical change from the above description.

(b) (i) From the above description, give one evidence that the liquid is water.

(ii) Suggest a chemical test to show that the liquid is water.

(c) (i) Identify the two gases formed during electrolysis.

(ii) Suggest tests to identify these two gases.

(9 marks)

7. The results of tests 1-3 with substances A and B are summarized in the following table:

Substance

Test 1:

Flame test

Test 2:

Addition of dilute nitric acid, followed by silver

nitrate solution

Test 3:

Addition of hydrochloric acid

A Golden yellow White precipitate is No observable change

flame formed

B Brick-red flame No observable change A gas is evolved which can turn limewater milky

(a) According to test 1, what metals are present in A and B respectively?

(b) According to tests 2 and 3, explain briefly what are present in A and B respectively.

(c) Name substances A and B.

(d) State ONE source of substances A and B respectively.

(e) What will happen if

(i) A is heated strongly?

(ii) B is heated strongly?

(12 marks)

8. Consider three substances: chalk, limestone and marble.

(a) (i) What is the common substance present in chalk, limestone and marble?

(ii) Suggest chemical tests for the presence of this substance in limestone.

(b) Which substance is the hardest?

(c) State the conditions for the conversion of limestone to marble.

(d) Suggest ONE use of limestone.

(e) A chalk is heated strongly.

(i) What will happen if chalk is heated strongly?

(ii) Water is added to the solid remained after heating. Solution Y is formed.

(1) Write a word equation for the reaction.

(2) State ONE use of solution Y.

(f) What will be observed when a piece of chalk is added into dilute hydrochloric acid? Write a word equation for the reaction.

(15 marks)

9. The following diagram shows some natural processes in our environment.

(a) What is Process 1?

(b) Classify the above processes into physical change(s) and chemical change(s).

(c) Explain briefly how rainwater causes the erosion of limestone.

(d) (i) What is the main constitute substance left after a sample of sea water is evaporated to dryness?

(ii) Suggest TWO uses of this substance in our daily lives.

(e) Pure water can be obtained from distillation of sea water.

(i) Does distillation of sea water involve a physical or chemical change?

(ii) Draw a labelled diagram of experimental set-up for simple distillation of

sea water.

(13 marks)

10. A student carried out an experiment on thermal decomposition of limestone.

(a) (i) What is the major component of limestone?

(ii) Give the name of a natural occurring substance which has the same major component as limestone.

(b) Write a word equation for thermal decomposition of limestone.

(c) A gas is evolved in thermal decomposition of limestone.

(i) Draw an experimental set-up to identify the gas.

(ii) State any observable change for the test. Write a word equation for the change.

(d) Describe briefly how you can test the presence of calcium ion in limestone.

(11 marks)

11. Answer the questions with reference to the diagram below.

(a) Name substances A, B and C.

(b) What should process X be?

(c) Write a word equation for

(i) the decomposition of substance A on strong heating; and

(ii) addition of dilute hydrochloric acid to substance A.

(d) When carbon dioxide is bubbled into substance C, what will be observed? Write the word equation for the reaction involved.

(e) A student wants to obtain pure calcium chloride crystals from calcium chloride solution.

(i) Describe briefly how he can obtain the crystals from the solution.

(ii) The student cannot distinguish between sodium chloride crystals and calcium chloride crystals. Suggest a chemical test that allows him to distinguish them.

(14 marks)

12. Describe briefly, using the following apparatus and materials, how you can distinguish hydrated calcium chloride crystals, calcium oxide and calcium carbonate.

Test tubes, a test tube holder, a Bunsen burner, limewater, dry cobalt(II) chloride papers, delivery tubes

(You are required give a paragraph-length answer. In this question, 6 marks will be awarded for chemical knowledge and 3 marks for effective communication.)

(9 marks)

13. Suppose you are provided with a mixture of impure sodium chloride powder and sand. Describe how you can obtain pure sodium chloride crystals from the mixture.

(You are required give a paragraph-length answer. In this question, 6 marks will be awarded for chemical knowledge and 3 marks for effective communication.)

(9 marks)