Term 2 · Class 6 Science · Chapter 4

Samacheer Class 6 Science - Air

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Chapter-wise textbook exercise answers for Air with validation-aware solutions.

Answers marked verified were checked during generation against the chapter context and source question text.
Sections in this chapter
I. Choose the correct answer: 5II. Fill in the blanks 1V. Arrange the following statements in correct sequence 1VI. Analogy 2VII. Observe the given figure carefully and answer the questions. 2VIII. Give a very short Answer 4IX. Give a short answer 2X. Answer in detail 2XI. Questions Based on Higher Order Thinking Skills. 1I. Choose the appropriate answer 3IV. Give very short answer 1
Your Progress - Chapter 40% complete
1I. Choose the correct answer:5 questions
Q.1……… is the percentage of nitrogen in the air.v
  1. A. 78%
  2. B. 21%
  3. C. 0.03%
  4. D. l%
Answer:

(a) 78%

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Q.2Gas exchange takes place in plants using _______v
  1. A. Stomata
  2. B. Chlorophyll
  3. C. Leaves
  4. D. Flowers
Answer:

(a) Stomata

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Q.3The constituent of air that supports combustion is ……….v
  1. A. Nitrogen
  2. B. carbon-di-oxide
  3. C. Oxygen
  4. D. water vapour
Answer:

(c) Oxygen

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Q.4Nitrogen is used in the food packaging industry because it _______v
  1. A. provides colour to the food
  2. B. provides oxygen to the food
  3. C. adds proteins and minerals to the food
  4. D. keeps the food fresh
Answer:

(d) keeps the food fresh

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Q.5……… and ………… are the two gases, which when taken together, make up about 99 percentage of air.v
  1. A. I and II
  2. B. I and III
  3. C. II and IV
  4. D. I and IV
Answer:

(d) I and IV

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2II. Fill in the blanks1 questions
Q.G1…………. is the active component of air. The gas given out during photosynthesis is ……….. ………. gas is given to the patients having breathing problems. ………. can be seen moving in a beam of sunlight in a dark room. …………. gas turns lime water milky.v
Answer:

Oxygen(O 2 )
Oxygen(O 2 )
Oxygen (O 2 )
Tiny dust particles
Carbon dioxide (CO 2 )

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3V. Arrange the following statements in correct sequence1 questions
Q.G31. 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.v
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.

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4VI. Analogy2 questions
Q.1Photosynthesis: ……….. :: Respiration : Oxygenv
Answer:

CO 2

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Q.278% of air : Does not support combustion :: ……… : Supports combustionv
Answer:

21% of air

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5VII. Observe the given figure carefully and answer the questions.2 questions
Q.1What will happen if we remove plants from the aquarium?v
Answer:

The production of O 2 and absorption of CO 2 and NH 3 will you reduced.
Plants provide shelter to fish, so, they feel insecure.
Algae growth will increase.

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Q.2What will happen if we remove the fish from the aquarium and keep it (with green plants) in a dark place? v
Answer:

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

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6VIII. Give a very short Answer4 questions
Q.1What is the atmosphere? Name the five layers of the atmosphere.v
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.

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Q.2How do the roots of land plants get oxygen for breathing?v
Answer:

Oxygen is present in the air spaces of soil. This O 2 is taken by root hairs through diffusion to the rest of the plant.

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

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

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Q.4What will happen if you breathe through your mouth?v
Answer:

Several health conditions and risk factors can lead to mouth breathing.
Snoring
dry mouth
daytime tired
Poor dental health

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7IX. Give a short answer2 questions
Q.1Biscuits kept open on a plate during monsoon days lose their crispness. Why?v
Answer:

During monsoon days, Water vapour from the atmosphere is absorbed in the biscuits. So the biscuits lose its crispness.

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Q.2Why do traffic assistants wear a mask on duty?v
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.

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8X. Answer in detail2 questions
Q.1How do plants and animals maintain the balance of oxygen and carbon-di¬oxide in air?v
Answer:

plants in forests release oxygen through the process of photosynthesis and help in providing oxygen to animals for respiration.
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.

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

The atmosphere is essential for life because it maintains an appropriate climate for the maintenance of life by carrying out the following activities:
The atmosphere keeps the average temperature of the Earth fairly constant during the day time.
It prevents a sudden increase in temperature during the day time.
It also slows down the escape of heat from the surface of the Earth into outer space during the night time.

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9XI. Questions Based on Higher Order Thinking Skills.1 questions
Q.1Can you guess why fire extinguishers throw a stream of carbon-di-oxide while putting – off fire?v
Answer:

It is because carbon-di-oxide (CO 2 ) does not support combustion. When sprayed on burning object it stops the supply of oxygen and controls the fire.

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10I. Choose the appropriate answer3 questions
Q.2_______ is responsible for making clouds.v
  1. A. Hydrogen
  2. B. Oxygen
  3. C. Water vapour
  4. D. Carbon-di-oxide
Answer:

(c) Water vapour

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Q.3A process without emitting flame is called as …………v
  1. A. Combustion
  2. B. Burning
  3. C. Cherring
  4. D. Melting
Answer:

(a) Combustion

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Q.4_______ was able to identify highly reactive gas called oxygen.v
  1. A. Lavoisier
  2. B. Ingenhousz
  3. C. Rutherford
  4. D. Joseph Priestley
Answer:

(d) Joseph Priestley

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11IV. Give very short answer1 questions
Q.2“Air is not an elementary substance, but a composition”. Why?v
Answer:

Air is a composite mixture of many gases like N 2 , O 2 , CO 2 and others.

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