Zusammenfassung der Ressource
Tests For Chemicals
- Gases
- Chlorine
- Bleaches damp litmus
paper (Turns white)
- Oxygen
- Relights a glowing splint
- Carbon Dioxide
- Turns lime water milky white
- Hydrogen
- Burns with a 'squeaky' pop
- Ammonia
- Turns damp RED litmus paper blue
- Water
- White Anhydrous
Copper(II) Sulphate
Powder
- Turns blue in presence of water
- BUT does not show if it is pure or not
- Pure water has specific physical
properties that can be tested
- Boiling point:
- 100ºC
- Melting point:
- 0ºC
- Cations
- Flame Tests For Metal Ions
- Li+ Lithium:
- Red Flame
- Na+ Sodium:
- Yellow Orange Flame
- K+ Potassium:
- Lilac Flame
- Ca2+ Calcium:
- Orange/Brick-Red Flame
- NaOH Precipitates
- Copper(II) Cu2+
- Blue
- Iron(II) Fe2+
- Sludgy Green
- Iron(III) Fe3+
- Reddish Brown
- Many Metal Hydroxides form precipitates when added to Sodium Hydroxide
as they are insoluble. The precipitate may have a distinctive colour
- Ammonium Compounds
- Add NaOH (Sodium Hydroxide)
- Test For Ammonia
- Damp litmus paper bleeches
- Anions
- Carbonates
- Add HCl to sample
- If Carbonate ions present CO2 will be given off
- This can be tested in lime water
- Sulphates
- Add HCL to remove impurities
- Then Add Barium Chloride
- If Sulphate present a white precipitate will form
- Halides
- Iodide = Yellow
- Bromide = Cream
- Add Nitric Acid to the sample
to remove impurities
- Then add Silver Nitrate Solution
- See colour of precipitate
- Chloride = White