Air composition — KCSE Chemistry

Air is primarily composed of nitrogen (78%), oxygen (21%), and other gases (1%). The industrial separation of air is achieved through fractional distillation, a process that exploits the different boiling points of its components.

Process of Fractional Distillation:

1. Cooling: Air is first cooled to a liquid state at around -200°C.
2. Distillation: The liquid air is then heated gradually in a fractionating column.
3. Separation: As the mixture heats, gases vaporize at different temperatures, allowing for separation:
   • Nitrogen (boiling point: -196°C) vaporizes first.
   • Oxygen (boiling point: -183°C) is collected next.
4. Collection: Other gases, such as argon and carbon dioxide, are separated later.

Uses of the Products:

• Nitrogen: Used in fertilizers, food preservation, and as an inert atmosphere in chemical reactions.
• Oxygen: Essential for respiration, used in medical applications, and in steel manufacturing.
• Argon: Used in welding and as a filler gas in light bulbs.

Understanding this process is crucial as it highlights how we can efficiently utilize air's components in various industries.

Air pollution is a major environmental issue caused by various pollutants. Common pollutants include:

• Carbon monoxide (CO): Emitted from vehicle exhausts and incomplete combustion.
• Sulfur dioxide (SO₂): Released from burning fossil fuels and industrial processes.
• Nitrogen oxides (NOₓ): Produced from vehicle engines and power plants.
• Chlorofluorocarbons (CFCs): Used in refrigeration and aerosol sprays.

Effects of air pollution:

• Respiratory diseases such as asthma and bronchitis.
• Environmental issues like acid rain and global warming.
• Damage to ecosystems and wildlife.

Control measures include:

• Promoting the use of public transport to reduce vehicle emissions.
• Implementing stricter regulations on industrial emissions.
• Encouraging the use of alternative energy sources.
• Banning or limiting the use of CFCs in products.

By understanding these pollutants, their effects, and control measures, we can work towards cleaner air and a healthier environment.

Air is a mixture of gases essential for life on Earth. The primary components of air include:

• Nitrogen (N₂): Approximately 78% of air, inert and does not support combustion.
• Oxygen (O₂): About 21% of air, vital for respiration and combustion.
• Argon (Ar): Roughly 0.93%, an inert gas with no significant biological role.
• Carbon Dioxide (CO₂): Around 0.04%, important for photosynthesis and greenhouse effect.
• Trace gases: These include neon, helium, methane, and others in very small amounts.

The composition of air can vary slightly based on location, altitude, and environmental conditions. For example, urban areas may have higher levels of pollutants like carbon monoxide and sulfur dioxide.

Understanding air composition is crucial for various applications, including environmental science, health, and industry. It helps in assessing air quality and understanding climate change.