GASES & ION

HideShow resource information
View mindmap
  • GASES & ION
    • TESTS FOR GASES
      • HYDROGEN:
        • TEST: mix with air and ignite using a lit splint
        • RESULT: burns with a squeaky pop
      • OXYGEN:
        • TEST & RESULT: relights a glowing splint
      • AMMONIA:
        • TEST: damp red litmus paper
        • RESULT: litmus paper turns blue
      • CHLORINE
        • TEST: damp blue litmus paper
        • RESULT: litmus paper turns red and then bleaches white
      • CARBON DIOXIDE
        • TEST: bubbled through limewater
        • RESULT: turns the limewater cloudy
    • GASES IN THE AIR
      • 78% Nitrogen
      • 21% Oxygen
      • 0.93% Argon
        • Argon is known as a noble gas because it is very unreactive
      • 0.04% Carbon Dioxide
      • Water vapour
    • TESTING FOR CATIONS
      • FLAME TESTS
        • Lithium = red
        • Sodium = orange
        • Potassium = lilac
        • Calcium = brick red
        • HOW  TO CARRY OUT A FLAME TEST
          • 1.  Clean a platinum wire loop by dipping it into hydrochloric acid and putting it in a flame (should burn without colour)
          • 2. Once the loop is clean, you can dip it into the sample you want to test and then put it back in the flame
      • TESTING FOR AMMONIUM IONS
        • TEST: add sodium hydroxide to the solid/solution being tested
        • RESULT: if ammonium ions are present then a pungent smelling gas is produced
      • PRECIPITAT-ION REACTIONS
        • METHOD: add sodium hydroxide solution to the solution being tested
        • RESULTS:
          • COPPER (II) blue precipitate
          • IRON (II) sludgy green precipitate
          • IRON (III) red/brown precipitate
    • OXYGEN
      • MAKING OXYGEN
        • Pure oxygen can be made using hydrogen peroxide (H202)
        • Hydrogen peroxide will decompose into water and oxygen
        • The decomposition is really slow but the rate of the reaction can be increased with a catalyst
          • CATALYST            =          Manganese oxide
            • A catalyst speeds up a reaction without being used up itself
        • Methods of collection
          • Gas syringe
          • Over water
      • WORKING OUT THE % OF OXYGEN IN THE AIR
        • COPPER EXPERIMENT
          • METHOD
            • 1. 100cm3 of air is passed over copper (which is being heated)
            • 2. When copper is heated, it reacts with oxygen in the air to make copper (II) oxide
              • So the reaction uses up oxygen
                • Therefore the volume of air decreases by about 20% (percentage of oxygen in the air)
        • IRON OR PHOSPHOR-OUS EXPERIMENT
          • % of oxygen = vol of oxygen used // vol of  air at start  x100
          • iron + oxygen + water ---> hydrated iron (II) oxide
          • METHOD:
            • 1. Iron wool is soaked in acetic acid and pushed into a test tube
              • CATALYST        =      ACETIC ACID
            • 2. The test tube is then inverted into a beaker of water
            • 3.Over time the level of water in the test tube will rise because the iron reacts with the oxygen to make iron oxide
    • CARBON DIOXIDE
      • MAKING CARBON DIOXIDE
        • Dilute hydrochloric acid reacts with calcium carbnate to produce carbon dioxide
        • Pieces of calcium carbonate (marble chips) are put in the bottom of a flask and dilute hydrochloric acid is added
        • The dilute hydrochloric acid reacts with the calcium carbonate to produce...
          • 1. Calcium chloride
          • 2. Water
          • 3. Carbon dioxide gas
        • Methods of collection
          • a gas syringe
          • using downward delivery (used to collect gases that are heavier than air)

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Testing and analysing substances resources »