Composition of Air and Gas Tests

Composition of Air

• Air is composed of different gases
  • Nitrogen accounts for 78%
  • Oxygen accounts for 21%
  • Carbon Dioxide accounts for 0.04%
  • Noble Gases
  • Water Vapor

Properties of Gases

• Different gases have different properties
  • Color
  • Odor
  • Flammability
  • Chemical Reactivity

Gas Testing Methods

Testing Oxygen

1. Observation of Color and Odor
   • Colorless, odorless
2. Flame Test
   • Burning Splint Test: Flame becomes brighter
   • Glowing Splint Test: Relights brightly
3. Chemical Substance Test
   • No observable change with oxygen

Testing Carbon Dioxide

1. Observation of Color and Odor
   • Colorless, odorless
2. Flame Test
   • Extinguishes the flame
3. Chemical Substance Test
   • Hydrogen Carbonate Indicator: Color changes from red to yellow
   • Lime Water: Becomes milky white

Testing Nitrogen

1. Observation of Color and Odor
   • Colorless, odorless
2. Flame Test
   • Extinguishes the flame
3. Chemical Substance Test
   • No change
   • No effective testing method

Testing Water Vapor

• Use dry Cobalt II Chloride paper
  • The paper is blue in a dry environment
  • Turns pink upon contact with water

Conclusion

• Odor and color cannot effectively distinguish between oxygen, nitrogen, and carbon dioxide
• The flame test effectively identifies oxygen
• Chemical reagents can effectively test for carbon dioxide
• Nitrogen currently has no effective testing method
• Water vapor can be tested with cobalt chloride paper