Question:
How will you show that air supports burning?
Answer:
Take a small burning candle. Cover the burning candle with a glass jar. After few minutes the candle is extinguished. As the supply of air is stopped due to glass jar the burning of candle is also stopped. This experiment proves that air supports burning
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.
Name the main component of air.
Q 5.
What is the source of carbon dioxide in air?
Q 6.
The component of air used by green plants to make their food, is………………….
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?
