Air
Introduction to Air
- Air is a mixture of gases, predominately made up of nitrogen (78%) and oxygen (21%).
- It also contains small amounts of other gases such as argon, carbon dioxide and various noble gases.
- Air is vital for life processes: oxygen is needed for respiration and carbon dioxide for photosynthesis.
- Because air is a mixture and not a compound, the gases retain their individual properties.
Components of Air
- Nitrogen (N₂): The most abundant component of air. It is used in the process of nitrogen fixation to produce nitrates in the soil, necessary for plant growth.
- Oxygen (O₂): It supports combustion and is required for aerobic respiration in living organisms.
- Argon (Ar): This is an inert gas that does not react readily with other substances. It’s often used when an unreactive atmosphere is needed, such as in light bulbs.
- Carbon Dioxide (CO₂): Although it’s the smallest component, it has a critical role in photosynthesis and climate regulation.
- Water Vapor (H₂O): This is the gaseous state of water. It helps in dispersing heat in the atmosphere and is vital for the water cycle.
- Trace gases: Includes gases like neon, helium, methane, and krypton, which are present in very small quantities.
Separation Techniques
- The techniques used to separate the components of air include fractional distillation and evaporation.
- Fractional distillation: It is used to separate a mixture of liquids with different boiling points. It’s used on a large scale to separate the components of air.
- Evaporation: This method is used to remove water vapor from the air.
Impact on Environment
- Air pollution: Emissions from industry and motor vehicles can pollute air, leading to health issues and environmental damage.
- Greenhouse effect: The accumulation of certain gases such as carbon dioxide, methane & water vapour traps heat within the earth’s atmosphere, causing global warming.
- Ozone layer depletion: Certain gases, in particular CFCs, can damage the earth’s ozone layer that shields the planet from harmful UV radiation.
- Acid rain: Certain pollutants in the air can react with water vapor to form acids, which fall as ‘acid rain’. This can have harmful effects on ecosystems and built environments.