Required Practicals

• Making salt crystals?

  • Take a base (e.g. powdered copper oxide) and mix with heated acid (e.g. concentrated sulphuric acid) to cause a neutralisation reaction that produces a salt (copper sulphate in this case)
  • Add copper oxide until excess, indicated by unreacted powder at the bottom of the beaker
  • Filter using filtration paper, then heat solution in an evaporating basin on a beaker of water over a tripod, gauze and a bunsen burner
  • Once the water has evaporated, dry the crystals produced by placing on filter paper
• Electrolysis?

  • Place carbon electrodes (inert) in a solution of the salt to be electrolysed
  • The solution contains H+ and OH- ions, if sodium chloride solution then Na+ & Cl - ions
  • If metal ions is more reactive than hydrogen, it will stay in solution and hydrogen will be reduced at the cathode to make H2 gas. If not, the metal is reduced instead
  • If non - metal ions is a halid (Cl-), it will be oxidised at the anode. We can prove this by testing with blue litmus paper and it should become bleached/white. If not a halide, oxygen gas is made at anode instead
• Temperature changes?

  • Measure volume of 30^cm3 of dilute hydrochloric acid via measuring cylinder
  • Put in polystyrene cup - acts as a good thermal insulator
  • Place cup in beaker for stability
  • Put 5cm^3 of sodium hydroxide into a 10cm^3 measuring cylinder
  • Pour sodium hydroxide into cup, fit lid & gently stir with thermometer through hole
  • Start a stopwatch, record temp. every 30 seconds
  • When readings stop changing, record final temp.
  • Repeat steps adding 5cm^3 of sodium hydroxide until 40cm^3
  • Repeat all steps & calculate mean
• Titration (pt1)?

  • Rinse conical flask & pipette with distilled water
  • Transfer 25cm^3 of alkali into conical flask
  • Add methyl orange indicator into conical flask
  • Rinse burette with distilled water & acid, then fix it on a stand
  • Fill burette with acid until meniscus is exactly zero
  • Place burette on white tile, & allow acid to trickle slowly into flask, while constantly swirling
  • When indicator changes colour, stop the tape to give an amount of acid needed
• Titration (pt2)?

  • Refill everything, and repeat steps, but this time close the tap 5cm^3 less than rough titration
  • Now add the acid drop by drop, keep swirling until methyl orange turns yellow to red
  • Once fully red, record the burette reading from the bottom of the meniscus, and repeat all steps until you have concordant results