chem required pracs paper 1

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Created by
Cait

Cards (7)

  • making soluble salts (crystals)
    1. start with a fixed volume of sulfuric acid.
    2. gently heat until almost boiling
    3. use a spatula to add small amounts of copper oxide and stir with a glass rod, the solution should go blue
    4. continue adding until powder remains after stirring, it is now in excess and all acid has been reacted and the solution is neutral
    5. filter the unreacted copper oxide with a funnel and filter paper
    6. place the solution in an evaporating basin and gently heat until half of it has evaporated
    7. leave for 24 hours to cool and form crystals
  • electrolysis: copper (II) chloride
    1. pour 50cm^3 of copper (II) chloride solution into a beaker
    2. place a lid on top with two holes and insert a carbon graphite rod into each hole (our electrodes), not touching
    3. attach crocodile leads to the rods and connect to a low voltage power supply and select 4V
    4. copper should be discharged at the cathode, and chlorine gas at the anode, which can be tested with damp blue litmus paper, which should go bleached
  • temperature changes
    1. measure 30cm^3 of dilute hydrochloric acid and transfer to a polystyrene cup supported by a beaker
    2. measure the temperature with a thermometer and record it in a table
    3. use a measuring cylinder to measure 5cm^3 of sodium hydroxide solution and transfer to the polystyrene cup
    4. add a plastic lid and a thermometer, and gently stir using it
    5. look for a temperature rise, when it stops changing record the highest temperature reached
    6. repeat with 10cm^3 of sodium hydroxide solution, and repeat increasing the solution by 5cm^3 until at 40cm^3, repeat everything and find a mean
  • test for oxygen
     If oxygen is present in a test tube, a glowing splint relights when it is held inside.
  • test for hydrogen
    If hydrogen is present in a test tube, a lighted splint held near its mouth ignites with a squeaky pop.
  • test for carbon dioxide
    If carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white.
  • test for chlorine
    Damp litmus paper is bleached white when it is placed in chlorine.
    If damp blue litmus paper is used, the paper turns red then white.