Science

Air Around Us

Question:

Write the necessary conditions for rusting of iron to take place.

Answer:

Rusting of iron takes place in the presence of moisture and air. So the presence of air and water vapour in air are two necessary conditions for rusting of iron.

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Air Around Us

Q 1.

What happens if the percentage of carbon-dioxide increases in the air?

Q 2.

What is the source of oxygen gas in air?

Q 3.

What is the percentage of nitrogen in air?
 

Q 4.

The component of air used by green plants to make their food, is………………….

Q 5.

Name the main component of air.

Q 6.

What is the source of carbon dioxide in air?

Q 7.

What is the composition of air?

Q 8.

Why does a lump of cotton wool shrink in water?

Q 9.

The layer of air around the earth is known as………………….

Q 10.

Name the main component of air.

Q 11.

What is wind energy? Mention its two advantages.
 

Q 12.

How will you prove that soil contains air in it?

Q 13.

Mention two uses of air.

Q 14.

Name the major gas present in the (a) inhaled air (b) exhaled air.

Q 15.

Why is air considered as a mixture?

Q 16.

Write the necessary conditions for rusting of iron to take place.

Q 17.

What is the percentage of oxygen in air?
 

Q 18.

Air is a mixture. Prove this statement.

Q 19.

Describe balance of oxygen in the air.

Q 20.

Which gas in the atmosphere is essential for respiration?

Q 21.

Explain why mountaineers carry oxygen cylinders with them?

Q 22.

Name a device which uses wind energy to generate electricity.

Q 23.

You must have seen during rainy season, when it rains the animals like earthworm, snakes, snails etc. are commonly seen. Explain why?

Q 24.

Name a device which uses wind energy to generate electricity.

Q 25.

Why do we see the sky and air clear and clean after rainfall?

Q 26.

How do plants and animals help each other in exchange of gases in the atmosphere?

Q 27.

What happens if the percentage of oxygen in the air reaches to 70%?

Q 28.

Name the main component of air.

Q 29.

What is wind energy? Mention its two advantages.
 

Q 30.

List five activities that are possible due to presence of air.

Q 31.

Mention one necessary condition for the combustion to take place.
 

Q 32.

Explain why during an incident of fire, one is advised to wrap a woollen blanket over a burning object.

Q 33.

Demonstrate through a simple experiment that the air mainly contains nitrogen and oxygen in the volume ratio of 4: 1.

Q 34.

Why is carbon-dioxide gas used to extinguish fire?

Q 35.

How will you show that air is dissolved in water?
 

Q 36.

What is air? Name the major constituents of air. Also give their volume proportions in air.

Q 37.

How will you show that air supports burning?