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  • FREE 5-MIN Notes
    • 1. Experimental Techniques
    • 2. Methods of Purification
    • 3. Separation Techniques
    • 4. Qualitative Analysis
    • 5. Kinetic Particle Theory
    • 6. Atomic Structure
    • 7. Elements, Compounds, Mixtures
    • 8. Ionic Bonding
    • 9. Covalent Bonding
    • 10. Mole Concept
    • 11. Electrolysis
    • 12. Energy Changes
    • 13. Speed of Reaction
    • 14. Redox
    • 15. Acids and Bases
    • 16. Salts
    • 17. Ammonia
    • 18. Periodic Table
    • 19. Metals
    • 20. Air
    • 21. Fuels
    • 22. Organic Chemistry
    • 23. Macromolecules
  • Free Printables

1. Experimental Techniques

Collection of gases
The method used for collecting a gas depends on two factors:
  • Molecular mass of as or density compared to air
  • Solubility of gas in water

EXAM TIP: Air has a molecular mass of approximately 28 or 29.

Upward delivery of gas: For gases which are soluble in water & less dense than air e.g. hydrogen
Downward delivery of gas: For gases which are soluble in water & more dense than air e.g. carbon dioxide
Displacement of water: Not for gases which are soluble in water e.g. NOT FOR ammonia and sulfur dioxide

Drying of gases
Drying agents are used to remove moisture from gases.

Neutral gases: hydrogen, oxygen
Acidic gases: chlorine, hydrogen chloride, sulfur dioxide
Alkaline gases: ammonia

Pass gas through fused calcium oxide: For drying neutral and alkaline gases. NOT FOR acidic gases.
Concentrated sulfuric acid: For drying neutral and acidic gases. NOT FOR alkaline gases.
Anyhydrous calcium chloride: For drying neutral, acidic and alkaline gases.

EXAM TIP: Anhydrous calcium chloride cannot be used to dry ammonia gas.

Apparatus
Stopwatch: For measuring time to the nearest 0.01s
Electronic balance
: For measuring mass to the nearest 0.01g
Thermometer: For measuring temperature to the nearest 0.5°C

Gas syringe: For measuring volume of gas to the nearest 0.5cm3
Measuring cylinder: For measuring volume of solution to the nearest 0.5cm3
Burette: For measuring variable & accurate volume of solution to the nearest 0.01cm3
Pipette: For measuring fixed & accurate volume of solution (25.0cm3)
Next: Methods of purification
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  • Home
  • More Information
  • Contact Me
  • Blog
  • FREE 5-MIN Notes
    • 1. Experimental Techniques
    • 2. Methods of Purification
    • 3. Separation Techniques
    • 4. Qualitative Analysis
    • 5. Kinetic Particle Theory
    • 6. Atomic Structure
    • 7. Elements, Compounds, Mixtures
    • 8. Ionic Bonding
    • 9. Covalent Bonding
    • 10. Mole Concept
    • 11. Electrolysis
    • 12. Energy Changes
    • 13. Speed of Reaction
    • 14. Redox
    • 15. Acids and Bases
    • 16. Salts
    • 17. Ammonia
    • 18. Periodic Table
    • 19. Metals
    • 20. Air
    • 21. Fuels
    • 22. Organic Chemistry
    • 23. Macromolecules
  • Free Printables