Chemical analysis

• What is the test for oxygen?

  Relights glowing splint
• What is the test for carbon dioxide?

  Turns lime water cloudy
• What is the test for chlorine?

  Bleaches damp litmus paper white
• What is the test for hydrogen?

  Squeaky pop test
• What is the colour of lithium ions in a flame test?

  Crimson
• What is the colour of sodium ions in a flame test?

  Yellow
• What is the colour of potassium ions in a flame test?

  Lilac
• What is the colour of calcium ions in a flame test?

  Orange-red
• What is the colour of copper III ions in a flame test?

  Green
• What is the colour of the precipitate formed when aluminium reacts with sodium hydroxide?

  White

  Does not dissolve in excess sodium hydroxide
• What is the colour of the precipitate formed when calcium reacts with sodium hydroxide?

  White

  Does not dissolve in excess sodium hydroxide
• What is the colour of the precipitate formed when magnesium reacts woith sodium hydroxide?

  White
• What colour precipitate is formed when copper II reacts with sodium hydroxide?

  Blue
• What colour precipitate is formed when iron II reacts with sodium hydroxide?

  Green
• What colour precipitate is formed when iron III reacts with sodium hydroxide?

  Brown
• Give 2 disadvantages of flame testing

  Colour can be difficult to distinguish

  Mixture of metal ions can mask the colour of the flame
• Give 3 advantages of instrumental methods

  Faster

  More accurate

  Sensitive
• What is the test for negative ions?

  Dilute acid --> efferevescence

  Bubble gas through lime water to see if it is cloudy
• What is the test for halide ions?

  Nitric acid + silver nitrate

  Produces coloured precipitate of silver halide
• What is the test for sulphate ions?

  Dilute HCl + barium chloride

  Produces white precipitate