Lesson 15 Air Around Us

What are the properties of air?

• Air occupies space.

• Air conducts electricity.

• Air has no colour and one can see through it.

• Air (oxygen) does not support burning.

Answer explanation

The properties of air is :-

1. Air occupies space.

2. Air has no colour and one can see through it.

What is the formula of nitrogen?

• N₂

• H₂O

• O₂

• SO₂

Answer explanation

The formula for Nitrogen is N₂.

____+____= CO₂

• N₂F₂ + O₂

• CF₂N₂ + SiH₂F

• O₂ + C₂

• C + O₂

Answer explanation

C + O₂ = CO₂

1 atom of carbon + 2 atoms of oxygen= Carbon dioxide

Which of the following are flammable?

• Water Vapour

• Helium

• Hydrogen

• Oxygen

Answer explanation

Hydrogen is the most flammable among these.

What is the percentage of oxygen in air?

• 21%

• 78%

• 99%

• 1%

Answer explanation

The percentage of oxygen in the air is 21%

Air is

• a opaque object

• a pure substance

• a mixture

• anything, that depends on the place where it is found

Answer explanation

Air is a mixture.

This air pollution causes various problems including _____ and _____.

• smog

• Plastic rain

• acid rain

• Voog

Answer explanation

This air pollution causes various problems including smog and acid rain.

Draw a picture of that part of the plant which exchange oxygen and carbon dioxide from air?

Envelope of air that surrounds the earth is known as

• biosphere

• ecosystem

• environment

• atmosphere

Answer explanation

Envelope of air that surrounds the earth is known as atmosphere.

O₂ is a supporter of

• Rusting

• combustion

• smoke

• dust

Answer explanation

Oxygen is a supporter of:-

Combustion

Rusting