Question:
What happens if the percentage of carbon-dioxide increases in the air?
Answer:
The increased percentage of carbon-dioxide will cause green house effect, i.e. it will not allow the hot rays of sun to escape from the atmosphere after reflection once they enter the earth's atmosphere, thereby increasing the temperature of earth, ice on mountains will melt and water level will rise.
Air Around Us
Q 1.
What is wind energy? Mention its two advantages.
Q 2.
What is the source of oxygen gas in air?
Q 3.
The component of air used by green plants to make their food, is………………….
Q 4.
Mention two uses of air.
Q 5.
What is the percentage of nitrogen in air?
Q 6.
What is the source of carbon dioxide in air?
Q 7.
What is the composition of air?
Q 8.
Name the major gas present in the (a) inhaled air (b) exhaled air.
Q 9.
What happens if the percentage of carbon-dioxide increases in the air?
Q 10.
What is the percentage of oxygen in air?
Q 11.
Why is air considered as a mixture?
Q 12.
Name the main component of air.
Q 13.
The layer of air around the earth is known as………………….
Q 14.
Why does a lump of cotton wool shrink in water?
Q 15.
How will you prove that soil contains air in it?
Q 16.
Name the main component of air.
Q 17.
Write the necessary conditions for rusting of iron to take place.
Q 18.
Describe balance of oxygen in the air.
Q 19.
Air is a mixture. Prove this statement.
Q 20.
Explain why mountaineers carry oxygen cylinders with them?
Q 21.
Name a device which uses wind energy to generate electricity.
Q 22.
Name a device which uses wind energy to generate electricity.
Q 23.
Why do we see the sky and air clear and clean after rainfall?
Q 24.
Which gas in the atmosphere is essential for respiration?
Q 25.
Name the main component of air.
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.
You must have seen during rainy season, when it rains the animals like earthworm, snakes, snails etc. are commonly seen. Explain why?
Q 29.
List five activities that are possible due to presence of air.
Q 30.
What is wind energy? Mention its two advantages.
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?
