Separating the given mixture Content: Iron – magnetic Calcium carbonate – insoluble Copper(II) sulfate – soluble Precaution: Iron needs to be separated as much as possible from the rest, before water is added. Otherwise iron will react with copper(II) sulfate solution to give a brown precipitate. DO NOT WANT!
Procedure – magnetic attraction Spread the mixture out in a petri dish. Use a magnetic to attract iron powders out the mixture, shake gently to remove the other two compounds from the magnet. Repeat the process to remove as much iron as possible.
Procedure – dissolution and filtration To the remaining mixture, add just enough water and stir to ensure all copper(II) sulfate is dissolved. (i.e. no more blue crystals left at the bottom.) A suspension of white solid in blue solution is formed. Filterthis suspension.
Procedure – washing and drying residue Wash the residue with a lot of distilled water, dry it between clean sheets of filter paper. This is the calcium carbonate.
Procedure – crystallization Heat the filtrate (a blue solution) gently in an evaporating dish, until crystals start to form at the edge of the solution. Let this saturated solution cool and crystalize. (After a few days) filter the crystal-solution mixture. Wash the crystals with little cold distilled water, and dry between clean sheets of filter paper. These are the copper(II) sulfate crystals.
A bit more on copper(II) sulfate crystallization.. This is an art installation in London:
Roger Hiorns: SEIZURE Visitors need to wear rain boots..