Chemistry
How would you prepare copper sulphate crystals from a mixture of charcoal and black copper oxide.
Answer
Copper sulphate crystals from a mixture of charcoal and black copper oxide
Method of preparation: Neutralisation of insoluble base
Reaction:
CuO + H2SO4 ⟶ CuSO4 + H2O
CuSO4 + 5H2O ⟶ CuSO4.5H2O (blue vitriol)
Procedure:
- Take dilute sulphuric acid in a beaker and heat it on wire gauze.
- Add black cupric oxide in small quantities at a time, with stirring till no more of it dissolves and the excess compound settles to the bottom.
- Filter it hot and collect the filtrate in a china dish. Evaporate the filtrate by heating to the point of crystallization and then allow it to cool and
- Collect the bright blue crystals of copper (II) sulphate pentahydrate CuSO4.5H2O (blue vitriol) and dry the crystals.
Related Questions
Answer the following questions related to salts and their preparations:
(a) What is a 'salt' ?
(b) What kind of salt is prepared by precipitation?
(c) Name a salt prepared by direct combination. Write an equation for the reaction that takes place in preparing the salt you have named.
(d) Name the procedure used to prepare a sodium salt such as sodium sulphate.
Explain the following methods with examples:
(a) Direct combination
(b) Displacement
(c) Double decomposition (precipitation)
(d) Neutralization of insoluble base
(e) Neutralization of an alkali (titration)
How would you prepare zinc sulphate crystals from zinc dust (powdered zinc and zinc oxide).
How would you prepare sodium hydrogen carbonate crystals.