Oxygen and Ozone: Chemical Reactions

Oxygen

• Oxygen is a chemical element with the symbol O and atomic number 8.
• It is a colorless, odorless, and tasteless gas at room temperature.
• Oxygen is the third most abundant element in the universe.
• It makes up a significant percentage of Earth's composition.

Ozone

• Ozone is a minor component of Earth's atmosphere, with a concentration of 0.02 to 0.1 ppm by volume.
• It absorbs ultraviolet (UV) radiation.
• The ozone layer is important for protecting life on Earth from harmful UV radiation.

Chapman Reaction

• The Chapman reaction is a cycle of chemical reactions that explains the formation and destruction of ozone in the stratosphere.

Sources of Free Oxygen

• Stratosphere:
  • UV photons below 242 nm break O₂ into free oxygen atoms (O).
  • The rate of oxygen production depends on season, latitude, and altitude.
  • Higher photochemical oxygen production occurs at the equator and high altitudes.
• Troposphere:
  • UV radiation above 30 km depletes O₂.
  • Ozone is produced at a rate similar to oxygen depletion.
  • Photochemical dissociation of NO₂ is a key source of oxygen in polluted tropospheres.

Ozone Variation

• Ozone concentration increases with altitude.
• The ozone layer provides protection from harmful UV radiation.

Dissolved Oxygen

• Dissolved oxygen (DO) is the amount of oxygen dissolved in water.
• It is essential for aquatic life.
• DO is higher in rapidly moving bodies of water and lower in stagnant water.

Factors Affecting Dissolved Oxygen

• Temperature: DO is inversely proportional to water temperature.
• Organic matter decomposition: Consumes oxygen, leading to lower DO levels in eutrophic conditions.
• Photosynthesis: Produces oxygen in aquatic systems.

Biological Oxygen Demand (BOD)

• BOD is a measure of the oxygen used by microorganisms to decompose waste.

This quiz explores the essential elements of oxygen and ozone, including their chemical properties and the Chapman reaction that explains the cycle of ozone formation and destruction. Understand the significance of free oxygen sources in the stratosphere and troposphere. Test your knowledge on these vital atmospheric components.