Mention one necessary condition for the combustion to take place. - Science

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Mention one necessary condition for the combustion to take place.



Presence of air.

Concept: Composition and Components of Air
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What are the causes of air pollution?

What is nitrogen-fixation?

Write ‘True’ or ‘False’ in front of following statement.

The trapping of solar heat energy in the earth’s atmosphere is called greenhouse effect.

Tick (√) the most appropriate answer.

A gas which dilutes the activity of oxygen in air is:

Tick (√) the most appropriate answer.

Which is not a polluting gas for the air?

Briefly state the importance of Oxygen.

Briefly state the importance of Nitrogen.

Briefly state the importance of Water vapour.

Name and briefly explain four ways by which pollution of air is caused by humans.

What do you observe when Ice cold water is filled in a glass tumbler.

Give reason:

When water is heated, we see bubbles rising up.

Fill in the blanks

Plants and animals maintain the balance of carbon ___________and _________ in the air.

Fill in the blank

Green plants need ________________to prepare food.

Name the components of air with their approximate percentage by volume in air. Does the percentage by volume of each component remain the same, in the atmosphere of different parts of the world? Explain with reasons.

With the help of a labeled diagram, describe a simple experiment to show the presence of oxygen and nitrogen in air using a piece of white phosphorus.

State the utility of oxygen for respiration in plants

Name the following:

The product of respiration released in exhaled air, other than carbon dioxide.

Give word equation for the following conversion:

Nitric oxide to nitrogen dioxide

Give word equation for the following conversion:

Nitrogen dioxide to nitric acid

Tabulate the various components of air, including the components with variable composition.

Name the main component of air.

What is the percentage of oxygen in air?

Why is air considered as a mixture?

Why is carbon-dioxide gas used to extinguish fire?

How will you prove that soil contains air in it?

Explain why mountaineers carry oxygen cylinders with them?

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

Air is a mixture of many _______.

_______ can be seen moving in a beam of sunlight in a dark room.

What is the composition of air?

Composition of the component of air ______ from place to place.

Air contains a small amount of CO2, Water vapour, and some other gases like ______, etc.

When air is moving with cool and soothing, it is called a cyclone.

The second major component of air is oxygen.

Air also contains a small amount of carbon-di-oxide, water vapour, and some other gases like argon,

The amount of water vapour in the air is more in windy places than in other areas.

The composition of air changes slightly from place to place. Give examples.

Give the components present in the air with a percentage?

“Air is not an elementary substance, but a composition”. Why?

Usha took a lump of dry soil in a glass and added water to it till it was completely immersed. She observed bubbles coming out. The bubbles contain

Explain the following observations very briefly

An empty glass in fact is not empty.


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