2010-08-12

Preparation of Soluble Salt - Copper(II) Sulphate


copper sulphate

The photo shows copper(II) sulphate prepared by one group of students in my chemistry class.
Copper(II) sulphate can be prepared by using one of the reactions
  1. sulphuric acid and copper(II) oxide
  2. sulphuric acid and copper(II) carbonate
Chemical equation for the first equation:
  1. H2SO4 + CuO  --> CuSO4 + H2O
  2. H2SO4 + CuCO3  --> CuSO4 + H2O
The slide follows briefly shows the steps taken. The copper(II) oxide can be replaced by copper(II) carbonate too.

Preparation of copper sulphate

In SPM 2003, students are required to describe a laboratory experiment to prepare dry magnesium chloride based on given materials :
  • magnesium sulphate solutions,
  • dilute hydrochloric acid,
  • potassium carbonate solution

 This question is a bit tricky. Students need to consider few things before write their plan:
  1. Is magnesium chloride a soluble salt?
  2. What are reactants used to prepare magnesium chloride?
  3. Are the reactants required given in the list?
  4. How to make use of the given materials?(Hint: precipitation reaction)
  5. Explain the procedure in details.
Need any further guide, just write in the comment!

8 comments:

  1. can you show me how to prepare dry magnesium chloride?I cannot find the answer

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  2. To prepare magnesium chloride, we need hydrochloric acid & magnesium carbonate or magnesium oxide or magnesium. We can prepare magnesium carbonate through the precipitation reaction(between magnesium sulphate & potassium carbonate. Then by adding magnesium carbonate into the hydrochloric acid.

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  3. Why do we get a white compound instead of blue crystals from the final product using sulphuric acid and copper 2 oxide?

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  4. Blue crystal as shown in the picture above is obtained when reacting sulphuric acid & copper(II) oxide.

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  5. what does the residue look like after you've filtered it, and what's the appearence of the filtrate?

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  6. The residue after filtration is shown in the picture above. Blue in colour.

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  7. Can u give me an introduction for this lab

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  8. how do you know whether it is the correct solution for preparing the particular salt? eg copper(II) chloride

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