Flame and precipitate tests

• How to distinguish between Al, Ca, Mg

  Add excess sodium hydroxide
• Aluminium

  Dissolves to form a colourless solution
• Carbonate ions 


  Add Hcl to solution, if bubbles form, co2 is present
• Sulphate ions


  Add HCL and barium chloride to solution, if a white precipitate forms, sulphate ions are present
• Halide ions 


  Add nitric acid and silver nitrate to solution
• Flame test (Metal ions)

  • Sterilise loop with roaring flame
  • Dip into compound being tested
  • Put into roaring flame
  • observe and record flame colour
• What does crimson represent? (Flame test)


  Lithium
• What does Yellow represent? (Flame test)


  Sodium
• What does Lilac represent ? (Flame test)


  Potassium
• What does orange-red represent? (Flame test)


  Calcium
• What does green represent? ( Flame test)


  Copper
• What does white represent? (Precipitate)


  Aluminium , Calcium and Magnesium
• What does green represent? (Precipitate)


  Iron(11)
• What does white represent? (Halide ions)


  Chloride
• What does cream represent? (Halide ions)


  Bromide
• What does yellow represent? (Halide ions)


  Iodide
• Instrumental analysis


  Benefits: Improved speed, accuracy and sensitivity
• Example of instrumental analysis 


  Flame emission spectra
• What does blue represent? ( Precipitate test)


  Copper