CHEMISTRY FORM THREE QUESTIONS AND ANSWERS
1. Identify the letter of the correct answer.
(i) Which of the following is not a compound of metal?
A: magnesium oxide B: aluminium oxide
C: sulphur dioxide B: iron (ii) iron (ii) sulphate
(ii) They used to soften water and manufacture glass.
A: carbonate compounds B: Nitrate compounds
(iii) Prepared by direct combination of metal and water.
A: oxides B: hydroxides C: Nitrates D: sulphates.
(iv) Carbon dioxide, water and salts are formed when they react with acid.
A: sulphates B: chlorides C: nitrates D: Carbonates
(v) Action of metals and dilute hydrochloric acid lead to formation of
A: chlorine B: chlorides C: sulphide D: sulphate
(vi) Which of the following compounds give oxides when heat?
A: copper nitrate and silver nitrate B: zinc nitrate and potassium carbonate
C: calcium nitrate and copper nitrate D: lead nitrate and silver nitrate
(vii) One of the following compounds can be used to remove hardness of water
A: calcium chloride B: Aluminium sulphate C: Potassium hydroxide D: aluminium nitrate
(viii) Does not give a metal oxide on heating.
A: copper nitrate B: lead nitrate C: calcium nitrate D: silver nitrate.
(ix) Aluminium sulphate is used to _____ impurity particles that found in water.
A: filter B: dissolve C: evaporate D: coagulate.
(x) _____ and _____ sulphates are insoluble in water.
A: Barium, lead B: sodium, potassium C: lead, aluminium D: magnesium, aluminium
2. Match items of list A and B
(i) Direct method of preparing metal hydroxides.
(ii) Method of preparing soluble metal carbonates.
(iii) Indirect method of preparing metal oxides.
(iv) Compounds of metals.
(v) Indirect method of preparing metal hydroxides.
(vi) Preparation of metal chlorides.
(vii) Method of preparing soluble metal sulphates.
(ix) Direct method of preparing metal oxides.
(x) Insoluble metal carbonates preparation.
A: Double decomposition method.
B: Action of metal carbonate, hydroxide or oxides with dilute sulphuric acid.
C: Direct heating of metals in air.
D: Have metals and nitrate group.
E: Action of metals and dilute hydrochloric acid.
F: A precipitation reaction in a salt solution or solution of alkali.
G: Passing excess carbon dioxide gas through a solution of a carbonate.
H: Thermal decomposition of carbonates, hydroxides or nitrates.
I: Calcium carbide is used.
J: Direct combination of metal and water.
K: Formed when metals undergo chemical reactions with other substances.
L: solution of soluble salt and that of alkali are used.
3. List down at least three (3) chemical properties of the following metal compounds.
4. Analyse at least three (3) uses of the following metal compounds.
5. With examples, explain the meaning of amphoteric oxides.
3. (a) Chemical properties of metal carbonates
-Some are soluble and some are insoluble in water.
- They react with acids to form salts.
Na2CO3 + 2HCl ----> 2NaCl + H2O + CO2
- They decompose on heating to form metal oxide and carbondioxide exept potassium carbonate and sodium carbonate.
CaCO3 --------> CaO + CO2.
(b) some of the chemical properties of oxides include the following.
-they react with water to form metal hydroxides.
-they react with dilute acids to form salts and water
-some metal oxides (amphoteric oxides) react with alkalis to form salts
4. (a) some of the uses of metal nitrates are
-used as fertilizer(NaNO3).
-used to make photographic film
(b) some of the uses of metal sulphates include
- used as plaster cast(CuSO4).
- used to manufacture ink(FeSO4)
- used to make pigments and medicines
5. Amphoteric oxides are metal oxides that may react with both acids and alkalis(bases).
Examples of amphoteric oxides are
They react with dilute acids to form normal salts.
ZnO + H2SO4 ------> ZnSO4 + H2O
They react with alkali to form complex salts.
ZnO + 2NaOH ------> Na2ZnO2 + H2O
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