[Physics Class Notes] on Air Composition Properties Pdf for Exam

The world we reside in is covered with air, called the atmosphere. Our atmosphere is composed of several gases. The gases it contains are:

• Oxygen

• Argon

• Carbon Dioxide

• Neon 

• Helium 

• Hydrogen

• Ozone, etc.

 

The most important gases are Oxygen, Nitrogen, and Carbon Dioxide. Air also contains water vapor and dust particles.

 

By volume, 78.084% of N2, 20.946% of O2, and 1% of trace gases together; these gases make the atmosphere. Trace gases are lesser in volume, but they are essential to us. The following diagram shows the constituents of air.

 

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What is the Composition of Air?

What do we take in for survival? We intake the oxygen. However,  the air we breathe doesn’t contain oxygen only; it has a composition of several gases. The characteristics of these gases are:

1. Nitrogen & oxygen are present in bulk in the atmosphere.

2. Carbon Dioxide, Helium, Ozone, Argon are present in a lesser amount.

3. Minute dust particles are also present in the atmosphere.

4. Plants require nitrogen for their survival, which they can’t take direction, so they take CO2 from the atmosphere. 

Therefore, bacteria present in the soil and the roots of plants take N2 and convert it into the form that is usable for plants.

Nitrogen is the plenteous gas in the atmosphere. Now, we will talk about other essential gases.

 

Oxygen

Oxygen is the second most copious gas in the air.

• During photosynthesis, plants release oxygen into the atmosphere.

• Humans and other living creatures take in oxygen for their survival.

 

Carbon Dioxide

 

Point to Ponder

The amount of carbon dioxide expelled by humans or other living beings appears to be equivalent to the amount used by the plants, thereby making an exact balance in the atmosphere. However, this statement doesn’t maintain verity, do you know why?

 

If We Talk About the Below-Mentioned Factors

 

The continuous discharge/emission of carbon dioxide is producing (creating) an imbalance in the atmosphere. That’s why the above statement is wrong.

 

Chemical Composition of Air

 The table lists the chemical composition of air:

 

The gases mentioned in the table are also known as the Principal Gases of Air.

 

Air and Its Properties

Air has the following properties:

1. Air takes up volume.

Air takes up the volume of the container it is kept in.

2. Air has mass/weight.

Take a balloon, measure its weight. Now, fill another balloon with air and measure its weight. You will note a difference in their weights.

3. Air is affected by altitude/height.

The higher we go, the lower is the air pressure. Everest climbers use oxygen tanks because, at higher altitudes, the oxygen becomes thin. These tanks help climbers breathe normally. 

4. Air is affected by temperature.

Higher is the temperature of the air, the faster the motion of air molecules.

5. Air exerts pressure in all directions.

On shaking the cold-drink bottle and removing its cap, carbon dioxide comes out with pressure and spreads in all directions.

6. Air is compressible.

Carbon dioxide inside the cold-drink bottle comes out with pressure on removing the cap of the bottle.

 

The Table Below Shows the Properties of Air

Did You Know?

• The troposphere, the lowest layer of the Earth’s atmosphere, contains three-quarters of all air. Air is a combination of gases, the majority of which are found in nature.

•  Air also includes a large quantity of man-made air pollutants, including some that are dangerous to breathe and others that contribute to global warming. 

• Water in all three phases (liquid, solid, and gas), as well as solid particles known as aerosols, are found in the troposphere.