Question:
Name the major gas present in the (a) inhaled air (b) exhaled air.
Answer:
(a) Oxygen (b) Carbon dioxide.
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.
What is wind energy? Mention its two advantages.
Q 11.
Name the main component of air.
Q 12.
Mention two uses of air.
Q 13.
How will you prove that soil contains air in it?
Q 14.
Why is air considered as a mixture?
Q 15.
Name the major gas present in the (a) inhaled air (b) exhaled air.
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?
