Students can download 6th Science Term 2 Chapter 4 Air Questions and Answers, Notes, Samacheer Kalvi 6th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 6th Science Solutions Term 2 Chapter 4 Air

Samacheer Kalvi 6th Science Air Text Book Back Questions and Answers

I. Choose the correct answer:

Question 1.
……… is the percentage of nitrogen in the air.
(a) 78%
(b) 21%
(c) 0.03%
(d) l%
Answer:
(a) 78%

Question 2.
Gas exchange takes place in plants using _______
(a) Stomata
(b) Chlorophyll
(c) Leaves
(d) Flowers
Answer:
(a) Stomata

Question 3.
The constituent of air that supports combustion is ……….
(a) Nitrogen
(b) carbon-di-oxide
(c) Oxygen
(d) water vapour
Answer:
(c) Oxygen

Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air

Question 4.
Nitrogen is used in the food packaging industry because it _______
(a) provides colour to the food
(b) provides oxygen to the food
(c) adds proteins and minerals to the food
(d) keeps the food fresh
Answer:
(d) keeps the food fresh

Question 5.
……… and ………… are the two gases, which when taken together, make up about 99 percentage of air.
I. Nitrogen
II. carbon-di-oxide
III. Noble gases
IV. Oxygen
(a) I and II
(b) I and III
(c) II and IV
(d) I and IV
Answer:
(d) I and IV

II. Fill in the blanks

  1. …………. is the active component of air.
  2. The gas given out during photosynthesis is ………..
  3. ………. gas is given to the patients having breathing problems.
  4. ………. can be seen moving in a beam of sunlight in a dark room.
  5. …………. gas turns lime water milky.

Answer:

  1. Oxygen(O2)
  2. Oxygen(O2)
  3. Oxygen (O2)
  4. Tiny dust particles
  5. Carbon dioxide (CO2)

III. True or False. If False, give the correct statement

  1. Inhaled air contains a large amount of carbon-di-oxide
  2. Planting trees help in decreasing global warming
  3. The composition of air is always exactly the same.
  4. Whales come up to the water surface to breathe in oxygen.
  5. The balance of oxygen in the atmosphere is maintained through photosynthesis in animals and respiration in plants.

Answer:

  1. False – (Inhaled air contains a large amount of oxygen)
  2. True
  3. False – (The composition of air changes slightly from place to place & also from season to season)
  4. True
  5. False – (The balance of oxygen in the atmosphere is maintained through Photosynthesis in plants & respiration in animals)

Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air

IV. Match the following

Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air 1
Answer:
1. – c
2. – b
3. – d
4. – e
5. – a

V. Arrange the following statements in correct sequence

1. Plants manufacture food by a process called photosynthesis.
2. Plants require energy for their growth.
3. Plants take in oxygen and release carbon-di-oxide just as animals.
4. Plants take carbon-di-oxide from the atmosphere, use chlorophyll in the presence of sunlight and prepare food.
5. Such oxygen is available to animals and human beings for breathing.
6. During this process, oxygen is released by plants.
Answer:
2. Plants require energy for their growth.
1. Plants manufacture food by a process called photosynthesis.
6. During this process, oxygen is released by plants.
3. Plants take in oxygen and release carbon-di-oxide just as animals.
5. Such oxygen is available to animals and human beings for breathing.
4. Plants take carbon-di-oxide from the atmosphere, use chlorophyll in the presence of sunlight and prepare food.

VI. Analogy

Question 1.
Photosynthesis: ……….. ::
Respiration : Oxygen
Answer:
CO2

Question 2.
78% of air : Does not support combustion ::
……… : Supports combustion
Answer:
21% of air

VII. Observe the given figure carefully and answer the questions.

Question 1.
What will happen if we remove plants from the aquarium?
Answer:

  1. The production of O2 and absorption of CO2 and NH3 will you reduced.
  2. Plants provide shelter to fish, so, they feel insecure.
  3. Algae growth will increase.

Question 2.
What will happen if we remove the fish from the aquarium and keep it (with green plants) in a dark place?
Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air 2
Answer:

  1. Most of the fishes require both periods of light and darkness.
  2. In a dark place, they will loose their sight and pigmentation.

Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air

VIII. Give a very short Answer

Question 1.
What is the atmosphere? Name the five layers of the atmosphere.
Answer:
Our earth is surrounded by a huge envelope of air called the atmosphere.
The atmosphere is made of five different layers – the Troposphere, the Stratosphere, the Mesosphere, the Ionosphere, and the Exosphere.

Question 2.
How do the roots of land plants get oxygen for breathing?
Answer:
Oxygen is present in the air spaces of soil. This O2 is taken by root hairs through diffusion to the rest of the plant.

Question 3.
What should be done if the clothes of a person catch fire accidentally? Why?
Answer:

  1. Cover the person in a rug or blanket and Roll him on the floor.
  2. This will cut off the air and put out the flames.
  3. A suitable fire extinguisher can also be chosen.

Question 4.
What will happen if you breathe through your mouth?
Answer:
Several health conditions and risk factors can lead to mouth breathing.

  1. Snoring
  2. dry mouth
  3. daytime tired
  4. Poor dental health

IX. Give a short answer

Question 1.
Biscuits kept open on a plate during monsoon days lose their crispness. Why?
Answer:
During monsoon days, Water vapour from the atmosphere is absorbed in the biscuits. So the biscuits lose its crispness.

Question 2.
Why do traffic assistants wear a mask on duty?
Answer:
Traffic assistants are continually exposed to smoke emitted out from the vehicles. Inhaling the pollutants in the smoke may cause breathing and lung problems. So they wear a mask on duty.

Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air

X. Answer in detail

Question 1.
How do plants and animals maintain the balance of oxygen and carbon-di¬oxide in air?
Answer:

  1. plants in forests release oxygen through the process of photosynthesis and help in providing oxygen to animals for respiration.
  2. Plants consume carbon dioxide released by the animals. In this way, plants help in maintaining a balance of oxygen and carbon dioxide in the atmosphere.

Question 2.
Why is the atmosphere essential for life on earth?
Answer:

The atmosphere is essential for life because it maintains an appropriate climate for the maintenance of life by carrying out the following activities:

  1. The atmosphere keeps the average temperature of the Earth fairly constant during the day time.
  2. It prevents a sudden increase in temperature during the day time.
  3. It also slows down the escape of heat from the surface of the Earth into outer space during the night time.

XI. Questions Based on Higher Order Thinking Skills.

Question 1.
Can you guess why fire extinguishers throw a stream of carbon-di-oxide while putting – off fire?
Answer:
It is because carbon-di-oxide (CO2) does not support combustion. When sprayed on burning object it stops the supply of oxygen and controls the fire.

Samacheer Kalvi 6th Science Air Additional Important Questions and Answers

I. Choose the appropriate answer

Question 1.
A layer consisted of water vapour which is responsible for making clouds is.
(a) Stratosphere
(b) Mesosphere
(c) Troposphere
(d) Exosphere
Answer:
(c) Troposphere

Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air

Question 2.
_______ is responsible for making clouds.
(a) Hydrogen
(b) Oxygen
(c) Water vapour
(d) Carbon-di-oxide
Answer:
(c) Water vapour

Question 3.
A process without emitting flame is called as …………
(a) Combustion
(b) Burning
(c) Cherring
(d) Melting
Answer:
(a) Combustion

Question 4.
_______ was able to identify highly reactive gas called oxygen.
(a) Lavoisier
(b) Ingenhousz
(c) Rutherford
(d) Joseph Priestley
Answer:
(d) Joseph Priestley

Question 5.
Which is used in refrigerating meat and fish?
(a) Liquid Ammonia
(b) Liquid Nitrogen
(c) Solid CO2
(d) Helium
Answer:
(c) solid CO2

II. True or False. If False, give the correct statement

  1. Oxygen is used for the synthesis of protein and fertilizers.
  2. CO2 turns calcium hydroxide solution to a milky white solution.
  3. The air in coastal areas have more oxygen.
  4. The role of chlorophyll is to absorb light from the sun.
  5. When cooled to -57°C, gaseous carbon-di-oxide becomes a liquid.

Answer:

  1. False – (Nitrogen is used for the synthesis of protein and fertilizers)
  2. True
  3. False – (The air in coastal areas have more water vapour)
  4. True
  5. False – (When cooled to -57°C, gaseous carbon-di-oxide becomes a solid)

III. Match the following

Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air 3
Answer:
i. – c
ii. – d
iii. – a
iv. – b

Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air

IV. Give very short answer

Question 1.
Where does Ozone layer lie?
Answer:
Ozone layer is present in stratosphere lies above the troposphere.

Question 2.
“Air is not an elementary substance, but a composition”. Why?
Answer:
Air is a composite mixture of many gases like N2, O2, CO2 and others.

Question 3.
Mention the percentage composition of Air.
Answer:
Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air 4

Question 4.
What is Burning?
Answer:
The process of firing of a substance in the presence of O2 and releasing a large amount of light and heat.

Question 5.
Define – Combustion. Give an example.
Answer:
The process of firing which does not emit flame is called combustion (fire without flame). Ex: Rocket propellants (fuel with oxygen).

V. Answer in detail

Question 1.
Briefly explain the process of ‘Photo Synthesis’.
Answer:

  1. Plants manufacture their food by ‘Photo Synthesis’.
  2. CO2 from the air and water from the solid react in the presence of sunlight to produce food.
    Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air 5
  3. Chlorophyll absorbs light from the sun.
  4. The liberated O2 during photosynthesis is much more than the O2 consumed by the plants for respiration.

Samacheer Kalvi 6th Science Guide Term 2 Chapter 4 Air

Question 2.
Mention the uses of Air.
Answer:

  1. For breathing by plants and Animals.
  2. For burning fuels like wood, coal, kerosene, LPG etc.,.
  3. Compressed air is used to fill tyres of vehicles.
  4. Maintaining the water cycle in nature. Because this air did not have O2 and CO2.
  5. O2 gas is used by patients in Hospitals, Climbers in mountains, Divers in Deepsea.