Air: Composition and Properties

Air is a mixture of gases that makes up the Earth's atmosphere. It is essential for the survival of living organisms and plays a crucial role in many natural processes.

Composition of Air

The major components of dry air are nitrogen (about 78%), oxygen (about 21%), and argon (about 0.9%). Trace amounts of other gases, such as carbon dioxide, neon, helium, and methane, are also present.

Physical Properties of Air

• Color: Air is colorless.
• Odor: Pure air has no distinct odor, but in urban areas, it may contain odorous pollutants.
• Taste: Air is tasteless.
• Density: The density of air is about 1.2 kg/m³ at sea level and 20°C. It decreases with increasing altitude.
• Pressure: Air exerts pressure, known as atmospheric pressure, which decreases with increasing altitude.
• Composition: Air is a mixture, not a compound, and its composition can vary slightly depending on location and environmental factors.

Chemical Properties of Air

Air is involved in various chemical reactions, including combustion, respiration, and the formation of pollutants. Oxygen in the air is essential for many combustion reactions, while nitrogen is relatively inert under normal conditions.

Study Guide

1. What are the major components of dry air?
2. Describe the physical properties of air.
3. Explain the concept of atmospheric pressure.
4. Discuss the chemical properties of air and its role in combustion reactions.
5. How does the composition of air vary with altitude?

[Air] Related Worksheets and Study Guides:

• Land, water, and airScience • First Grade