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.