15. Estimation of copper in copper(II) salts

  • 00:24 Why is it important to have a precise digital balance?
  • 00:46 Why is it important to rinse and keep the rinse-water?
  • 01:04 Why is it important to swirl thoroughly?
  • 01:05 What reaction occurs between the KI and the copper(II) sulfate?
  • 01:09 With what is the starch reacting?
  • 01:29 When the starch loses its blue-black colour, what does this tell you?
  • digital balance (pref. 3-decimal places but minimum 2-dp)

  • weighing boat

  • 2 x 50 cm3 beakers

  • 250 cm3 beaker

  • 3 x 250 cm3 conical flask

  • 250 cm3 volumetric flask with stopper

  • 25 cm3 volumetric pipette and filler

  • burette, funnel, stand

  • white tile

  • wash-bottle of de-ionised water

  • 2 x Pasteur pipette

Hazard Risk Control measure

CuSO4.5H2O crystals – moderate health hazard, corrosive, hazardous to the aquatic environment

Contact with eyes and skin

Eye: flood with water (10 min). See doctor.
Skin: wash with plenty of water. 

KI powder – irritant
0.1mol dm-3 Na2S2O3 solution – no hazard.
0.2% starch solution – no hazard.

Contact with eyes and skin.

Eye: flood with water (10min). See doctor.

Skin: wash with plenty of water.