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chemical tests (gas tests (hydrogen gas (method (insert a lighted splint…

- - - - insert a lighted splint into the test tube.
    - - he lighted splint should extinguish with a characteristic "pop" sound
  - - - take a glowing splint and place it in a sample of gas
    - - if it re-ignites the gas is oxygen
  - - - bubble it through lime water
    - - A positive test will result in the lime water turning milky.
  - - - damp red litmus paper or damp universal indicator (pH) paper
    - - turns blue or purple
  - - - damp litmus paper
    - - turns white
- - - - Aluminium (Al3+) : White Precipitate
        Dissolves as more NaOH is added to the solution
      - Calcium (Ca2+) : White Precipitate
        Will not dissolve in the NaOH solution
      - Copper (Cu2+) : Pale blue
      - Iron(II) (Fe2+) : Pale green
      - Iron(III) (Fe3+) : Red-brown
  - - - Add aqueous sodium hydroxide to the solid, or solution, under test and warm the mixture.
    - - If ammonium ions are present then a pungent-smelling gas is produced. The gas produced turns
        damp red litmus paper blue. It is ammonia, NH3.
- - - - Iodide, I- Yellow precipitate
      - Bromide, Br- Cream precipitate
      - Chloride, Cl- White precipitate
- - - - observe and record the flame colour produced
      - put the loop into the edge of the blue flame from a Bunsen burner
      - dip a clean wire loop into a solid sample of the compound being tested
  - - - Lithium(Li+) : Red
      - Sodium(Na+) : Yellow
      - Potassium(K+) : Lilac
      - Calcium(Ca2+) : Orange-red
      - Barium(Ba2+) : Green
      - Copper(Cu2+) : Blue-green