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Chemistry Form 4 • MODULE

4 The diagram below shows the flow chart for the preparation of zinc carbonate and zinc sulphate through reactions I
and II.
Rajah di bawah menunjukkan carta aliran bagi penyediaan garam zink karbonat dan zink sulfat melalui tindak balas I dan tindak balas II.
Reaction I Reaction II
Zinc nitrate Tindak balas I Zinc carbonate Tindak balas II Zinc sulphate
Zink nitrat Zink karbonat Zink sulfat

(a) Based on the flow chart above, classify the above salt to soluble salt and insoluble salt.
Berdasarkan carta aliran di atas, kelaskan garam di atas kepada garam larut dan garam tak larut.
Soluble salt / Garam larut : Zinc nitrate, zinc sulphate
Insoluble salt / Garam tak larut : Zinc carbonate
(b) (i) State the reactant for the preparation of zinc carbonate from zinc nitrate in reaction I.
Nyatakan bahan tindak balas untuk penyediaan zink karbonat dalam tindak balas I.
Sodium carbonate solution / potassium carbonate solution / ammonium carbonate solution
(ii) State the type of reaction the occurs in reaction I.
Nyatakan jenis tindak balas yang berlaku dalam tindak balas I.
Double decomposition

(iii) Describe the preparation zinc carbonate from zinc nitrate in the laboratory through reaction I.
Huraikan penyediaan zink karbonat dari zink nitrat melalui tindak balas I.
– 50 cm of 1 mol dm zinc nitrate solution is added to 50 cm of 1 mol dm sodium carbonate solution in a
3
–3
3
–3
beaker.
– The mixture is stirred with a glass rod and a white solid, ZnCO 3 is formed.
– The mixture is filtered and the residue is rinsed with distilled water.

– The white precipitate is dried by pressing it between filter papers.
(iv) Write the chemical equation for the reaction in (b)(iii).
Tuliskan persamaan kimia untuk tindak balas yang berlaku dalam (b)(iii).
Zn(NO ) + Na CO ZnCO + 2NaNO
2
3 2
3
3
3
(c) (i) State the reactant for the preparation of zinc sulphate from zinc carbonate in reaction II.
Nyatakan bahan tindak balas bagi penyediaan zink sulfat dari zink karbonat dalam tindak balas II.
Sulphuric acid
(ii) Describe laboratory experiment to prepare zinc sulphate from zinc carbonate through reaction II.
Huraikan eksperimen dalam makmal untuk menyediakan zink sulfat dari zink karbonat melalui tindak balas II.
3
– 50 cm of 1 mol dm of sulphuric is measured and poured into acid in a beaker.
–3
– The white precipitate from reaction I/ zinc carbonate powder is added to the acid until in excess.
– The mixture is stirred with a glass rod.
– The excess white precipitate is filter out.

– The filtrate is poured into an evaporating dish.
– The salt solution is gently heated until saturated.

– The hot saturated salt solution is allowed to cool for crystals to form.
– The crystals formed are filtered and dried by pressing it between sheets of filter papers.
(iii) Write the chemical equation for the reaction in (c)(ii).
Tuliskan persamaan kimia untuk tindak balas yang berlaku dalam (c)(ii).
ZnCO 3 + H 2 SO 4 ZnSO 4 + H 2 O + CO 2

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07-Chem F4 (3p).indd 149 12/9/2011 5:55:22 PM