Preparing Copper Sulfate

• How could you prepare pure, dry copper sulfate crystals from copper oxide?

  React sulfuric acid with excess copper oxide, filter to remove the excess copper oxide, heat the filtrate to start evaporation, turn of the heat and leave until all the water has evaporated, left with copper sulfate crystals.
• Why shouldn’t you evaporate all the water from the Bunsen burner?


  The copper sulfate crystals would start to decompose if continually heated, hot copper sulfate crystals would spit out, this could damage skin and eyes
• Sulfuric acid is warmed in a water bath before the copper oxide is added. Why?

  The reaction is faster with warm acid, this ensures all the acid reacts.
• Why is copper oxide added in excess to the sulfuric acid when preparing pure copper sulfate crystals?

  To ensure all the sulfuric acid reacts and that any excess copper oxide can be filtered out.
• What is a base?

  Any substance which reacts with an acid to form salt and water only.
• Write the chemical equation for the reaction between CuO and H2SO4.

  CuO + H2SO4 -> CuSO4 + H2O
• What colour is CuSO4(aq)?

  Blue
• During filtration, what is the filtrate and what is the residue?

  Filtrate - the liquid that has passed through the filter.

  Residue - the solid which remains in the filter paper.
• What safety precautions need to be considered when preparing a pure dry salt from an insoluble compound?

  Bunsen burner should be turned off or out on the safety flame when no it use, tie hair back, keep flammable chemicals away from the flame. Sulfuric acid is corrosive so wear eye protection.
• How can you seperate an insoluble product from a solution?

  Filtration, place filter paper over a conical flasl, pour mixture through the funnel, insoluble product left on the filter paper.
• How could you separate a soluble solid from a solution, if the solid decomposes when heated?

  Crystallisation, pour the solution into an evaporating dish and heat gently. When the crystals start to form, remove the dish from the heat and leave to cool. Once cold, filter the crystals out of the solution and leave them in a warm place to dry.