Air and Atmosphere - ICSE Class 6 (Chemistry)

🌬️ ICSE Class 6 Chemistry
Air and Atmosphere

80+ Questions MCQ · Fill · T/F · Short · Long

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Exercise I (1-5) Exercise II (6-13) Exercise III (14-18) DPP (19-38) Fill (39-46) T/F (47-51) Short (52-64) Long (65-69)

📝 Exercise I: Basic Air Composition

1-5

MCQ 1

Air consists of:
(a) only oxygen (b) only nitrogen (c) only carbon dioxide (d) all of these

✅ Answer: (d) All of these

MCQ 2

The most abundant gas in Earth's atmosphere is:
(a) oxygen (b) nitrogen (c) carbon dioxide (d) argon

✅ Answer: (b) Nitrogen

MCQ 3

Which gas supports burning?
(a) oxygen (b) nitrogen (c) carbon dioxide (d) water vapour

✅ Answer: (a) Oxygen

MCQ 4

Air is a mixture because:
(a) Components retain individual properties
(b) Energy change occurs
(c) Composition same everywhere
(d) Cannot be separated physically

✅ Answer: (a) Components retain individual properties

MCQ 5

Oxygen in air is:
(a) 4/5 parts (b) 1/5 parts (c) 1/3 parts (d) negligible

✅ Answer: (b) 1/5 parts

📝 Exercise II: Processes & Gases

6-13

MCQ 6

Rust is:
(a) Hydrated iron oxide (b) Hydrated copper sulphate
(c) Anhydrous iron oxide (d) None

✅ Answer: (a) Hydrated iron oxide

MCQ 7

Photosynthesis:
(a) Takes in oxygen (b) Takes in CO₂
(c) Takes in nitrogen (d) None

✅ Answer: (b) Takes in CO₂ and gives out O₂

MCQ 8

Fuels that leave no residue:
(a) Coal & wood (b) Coal & LPG
(c) Wood & CNG (d) LPG & CNG

✅ Answer: (d) LPG & CNG

MCQ 9

Respiration:
(a) Slow process (b) Natural & continuous
(c) Takes place at body temperature (d) All

✅ Answer: (d) All

MCQ 10

Common in combustion & respiration:
(a) Oxygen (b) Nitrogen (c) Heat & light (d) None

✅ Answer: (a) Oxygen

MCQ 11

Gas needed for protein synthesis:
(a) Oxygen (b) Nitrogen (c) Ozone (d) CO₂

✅ Answer: (b) Nitrogen

MCQ 12

Gas controlling climatic conditions:
(a) Inert gases (b) Oxygen (c) Water vapour (d) Nitrogen

✅ Answer: (c) Water vapour

📝 Exercise III: Pollution & Environment

13-18

MCQ 13

Air pollution caused by:
(a) Cutting trees (b) Factory smoke
(c) Harmful gases (d) All

✅ Answer: (d) All

MCQ 14

Gases causing acid rain:
(a) SO₂ & O₂ (b) N₂ & O₂
(c) CO₂ & H₂O (d) NO₂ & SO₂

✅ Answer: (d) NO₂ & SO₂

MCQ 15

Not a greenhouse gas:
(a) CO₂ (b) SO₂ (c) Methane (d) Nitrous oxide

✅ Answer: (b) SO₂

MCQ 16

Pollutants causing respiratory diseases:
(a) Ozone (b) Inert gases
(c) Dust & smoke (d) Water vapour

✅ Answer: (c) Dust & smoke

MCQ 17

Gas responsible for ozone depletion:
(a) Oxygen (b) CFCs (c) CO₂ (d) SO₂

✅ Answer: (b) CFCs

💪 DPP (Daily Practice Problems)

18-38

DPP 18

Not an impurity in air:
(a) SO₂ (b) N₂ (c) CO (d) NO₂

✅ Answer: (b) N₂

DPP 19

Supports combustion:
(a) CO₂ (b) N₂ (c) O₂ (d) None

✅ Answer: (c) O₂

DPP 20

Magnesium burns to form:
(a) Mg(OH)₂ (b) MgCO₃ (c) MgO (d) MgSO₄

✅ Answer: (c) Magnesium oxide

DPP 21

Ozone layer is in:
(a) Thermosphere (b) Mesosphere
(c) Stratosphere (d) Troposphere

✅ Answer: (c) Stratosphere

DPP 22

Most abundant inert gas:
(a) Helium (b) Neon (c) Argon (d) Krypton

✅ Answer: (c) Argon

DPP 23

Breakdown of food using oxygen:
(a) Burning (b) Combustion
(c) Photosynthesis (d) Respiration

✅ Answer: (d) Respiration

DPP 24

Gas used in observatory balloons:
(a) Helium (b) Neon (c) Argon (d) Krypton

✅ Answer: (a) Helium

DPP 25

Gas liberated during photosynthesis:
(a) NO₂ (b) O₂ (c) CO₂ (d) SO₂

✅ Answer: (b) O₂

DPP 26

Why CO is called silent killer?

✅ Answer: Because it is colourless, odourless, tasteless & poisonous.

DPP 27

Justify air is mixture.

✅ Answer: Composition varies; components retain properties; separable physically.

DPP 28

Incorrect statement about atmosphere:
(a) Contains gases (b) Contains water vapour
(c) Allows UV rays fully (d) Has dust particles

✅ Answer: (c) Allows UV rays fully (Ozone layer blocks most UV)

DPP 29

Common product in burning and respiration:

✅ Answer: CO₂

DPP 30

Test oxygen in cave:

✅ Answer: Use burning stick — if it burns, oxygen present.

DPP 31

Gas responsible for window condensation:

✅ Answer: Water vapour

DPP 32

Pollutant gas among:
O₂, N₂, H₂S, Ar

✅ Answer: H₂S (Hydrogen sulphide)

DPP 33

Gas turning limewater milky:

✅ Answer: CO₂

DPP 34

Demonstrate dust in air:

✅ Answer: Sunlight beam experiment — dust visible in light path.

DPP 35

Why nitrogen not decreasing?

✅ Answer: Nitrogen cycle balances it.

DPP 36

Nitrogen is present in:
(a) DNA (b) Protein (c) Chlorophyll (d) All

✅ Answer: (d) All

DPP 37

Acid rain gases:

✅ Answer: NO₂ & SO₂

DPP 38

Layer protecting from UV rays:

✅ Answer: Ozone layer (Stratosphere)

📋 Fill in the Blanks

39-46

Fill 39

Layer of air around earth is ______.

✅ Answer: atmosphere

Fill 40

Air is a ______ of gases.

✅ Answer: mixture

Fill 41

Plants maintain balance of ______ and ______.

✅ Answer: oxygen and carbon dioxide

Fill 42

Supporter of combustion is ______.

✅ Answer: oxygen

Fill 43

Green plants need ______ for photosynthesis.

✅ Answer: carbon dioxide

Fill 44

Rust is ______ iron oxide.

✅ Answer: hydrated

Fill 45

Major component of air is ______.

✅ Answer: nitrogen

Fill 46

Ozone layer protects from ______ rays.

✅ Answer: ultraviolet

🔘 True / False

47-51

T/F 47

Air is a compound.

✅ Answer: False

T/F 48

Major component of air is oxygen.

✅ Answer: False (Nitrogen is major)

T/F 49

Respiration needs nitrogen.

✅ Answer: False (Needs oxygen)

T/F 50

Lavoisier discovered composition of air.

✅ Answer: True

T/F 51

Polluted air is harmful for health.

✅ Answer: True

📝 Short Answer Questions

52-64

SA 52

Define atmosphere.

✅ Answer: The layer of air surrounding the Earth is called atmosphere.

SA 53

Define wind.

✅ Answer: Moving air is called wind.

SA 54

Why cannot we see air?

✅ Answer: Air is transparent and colourless.

SA 55

Importance of dust particles in air.

✅ Answer: Dust particles help in condensation of water vapour to form clouds.

SA 56

Define combustion.

✅ Answer: Burning of a substance in presence of oxygen to produce heat and light is combustion.

SA 57

Define respiration.

✅ Answer: The process of taking in oxygen and giving out carbon dioxide to release energy is respiration.

SA 58

Define photosynthesis.

✅ Answer: Process by which green plants make food using CO₂, water and sunlight, releasing oxygen.

SA 59

Define rusting.

✅ Answer: Slow conversion of iron into hydrated iron oxide in presence of oxygen and moisture.

SA 60

Conditions required for rusting.

✅ Answer: Oxygen and moisture (water) are essential for rusting.

SA 61

Why is nitrogen called a diluent?

✅ Answer: Nitrogen dilutes the activity of oxygen and slows down burning and rusting.

SA 62

Name two greenhouses gases.

✅ Answer: CO₂, Methane, Water vapour, Nitrous oxide (any two)

SA 63

What is acid rain?

✅ Answer: Rain containing dissolved oxides of nitrogen and sulphur (NO₂, SO₂) forming acids.

SA 64

What is ozone layer?

✅ Answer: Layer of ozone gas in stratosphere that protects Earth from UV rays.

📚 Long Answer Questions

65-69

LA 65

Write the composition of air with approximate percentages.

✅ Answer:
Nitrogen — 78%
Oxygen — 21%
CO₂ — 0.03–0.04%
Others — Argon, Neon, Helium, Water vapour, Dust

LA 66

Explain different layers of atmosphere.

✅ Answer:
Troposphere: Lowest layer, weather changes occur.
Stratosphere: Contains ozone layer.
Mesosphere: Meteors burn here.
Thermosphere: Satellites orbit, very high temperature.

LA 67

Explain Nitrogen cycle briefly.

✅ Answer:
Nitrogen from air is fixed by bacteria/lightning into soil → plants absorb → animals eat → decomposition returns nitrogen to air. This maintains balance.

LA 68

Difference between Respiration and Combustion.

✅ Answer:
Respiration: Slow process, occurs in cells, no flame, energy released in steps.
Combustion: Fast process, produces heat & light, flame may be present.

LA 69

Difference between Burning and Rusting.

✅ Answer:
Burning: Fast process, produces heat/light, new substance formed.
Rusting: Slow process, no heat/light, iron changes to hydrated iron oxide.

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Air and Atmosphere

ICSE Class 6 Chemistry · 80+ Handpicked Questions with Answers. MCQ · Fill · T/F · Short · Long & Extra.

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