What is the composition of air?
Which gas in the atmosphere is essential for respiration?
How will you show that air supports burning?
How will you show that air is dissolved in water?
Why does a lump of cotton wool shrink in water?
The layer of air around the earth is known as………………….
The component of air used by green plants to make their food, is………………….
List five activities that are possible due to presence of air.
How do plants and animals help each other in exchange of gases in the atmosphere?
VERY SHORT ANSWER TYPE QUESTIONS
Name the main component of air.
What is the source of oxygen gas in air?
What is the percentage of nitrogen in air?
What is the percentage of oxygen in air?
What is the source of carbon dioxide in air?
Mention one necessary condition for the combustion to take place.
SHORT ANSWER TYPE QUESTIONS
Why is air considered as a mixture?
Name the major gas present in the (a) inhaled air (b) exhaled air.
Write the necessary conditions for rusting of iron to take place.
Name a device which uses wind energy to generate electricity.
What is wind energy? Mention its two advantages.
6. Mention two uses of air.
7. Describe balance of oxygen in the air.
8. What happens if the percentage of oxygen in the air reaches to 70%?
9. What happens if the percentage of carbon-dioxide increases in the air?
10. You must have seen during rainy season, when it rains the animals like earthworm, snakes, snails etc. are commonly seen. Explain why?
11. Why is carbon-dioxide gas used to extinguish fire?
12. How will you prove that soil contains air in it?
13. Why do we see the sky and air clear and clean after rainfall?
14. Explain why mountaineers carry oxygen cylinders with them?
15. Explain why during an incident of fire, one is advised to wrap a woollen blanket over a burning object.
LONG ANSWER TYPE QUESTIONS
1. What is air? Name the major constituents of air. Also give their volume proportions in air.
2. Demonstrate through a simple experiment that the air mainly contains nitrogen and oxygen in the volume ratio of 4: 1.
3. Air is a mixture. Prove this statement.