Metals and their compounds
Extraction of metals: it is the process by which metals are isolated from their ore. The extraction of metals is basically a reduction process during which the Metallic ions are reduced to their corresponding metals atoms. This can be done electrically or by chemical and thermal processes.
Activity series of metals and methods of metal extraction
| Metal | Reactivity | Most common ore | Method of extraction |
| Potassium, k Sodium, Na Calcium, Ca | Very reactive | Chlorides Chlorides and trioxocarbonate IV oxides | Electrolysis of fused hydroxides and chlorides Electrolysis of fused chloride |
| Magnesium, MgAluminium, AlZinc, ZnIron, FeTin, SnLead, Pb | ModeratelyReactive | Oxides, trioxocarbonate IV and sulphides | Electrolysis of oxidesRoasting of trioxocarbonate IV and sulphides to form oxides; reduction of oxides by coke or carbon II oxide. |
| Copper, CuMercury, HgSilver, AgGold, Au | LeastReactive | Sulphides Free element | Heating in air Mined as free elements. |
Alloys
An alloy is a metallic substance consisting of a mixture of two or more metals or of a metal with a non metal such as carbon to obtain desirable properties.
Alloys are economically important and more useful than pure metal. Examples of alloy and their uses are as follows;
| Alloy | Uses |
| Brass | For making nuts, bolts, tubes, rods, ornaments, moving parts of clocks and watches, musical instruments and for general metal work. |
| Bronze | For making coins and medals; sculptures and for general metal work. |
| Steel | Construction of bridges, ships, cars and machinery. |
| Stainless steel | Making cutlery, tools and surgical instruments. |
| Duralumin | Construction of aircraft, ships, cars, spacecraft and moving parts of machines. |
| Soft solder | For welding and plumbing and also for printing. |
| Permallory | For making Electromagnets. |
| Alnico | For making permanent magnets. |
Properties of sodium and uses
1. Sodium is a silvery soft solid with a Metallic lustre.
2. It has a density of 0.97gcm-3
3. It is a good conductor of heat and electricity
4. It has a melting point of 98°C and boiling point of 883°C
Uses of sodium
1. Liquid sodium is used as a coolant in nuclear reactors
2. Sodium is used in manufacturing compounds such as sodium peroxide, sodamide and sodium cyanide.
3. It is used in sodium vapour lamps which give a bright-yellow light used for lighting highways, air ports and streets.
4. It is used in the production of lead IV Tetra ethyl which serves as an anti knock agent in petrol.
5. Mixtures of sodium and ethanol or sodium amalgam and water are used as reducing agents in organic chemistry.
6. It is used as a reducing agent in extraction of titanium.
Properties of calcium
1. Calcium is malleable and ductile
2. Calcium is a good conductor of heat and even electricity.
3. The melting and boiling point of calcium are 851°C and 1487°C respectively.
4. Calcium consists of a soft silvery grey metal.
5. It density is about 1.55gcm-3
Uses of calcium
1. It can be used as a dehydrating agent to prepare a pure ethanol.
2. It can also be used to extract uranium
3. It is also used to remove impurities from crude oil
4. Calcium can be used to produce calcium Fluoride and calcium hydride
Properties of copper
1. Copper is reddish brown in colour and the texture in the form of metal is soft.
2. It has a melting point of 1080°C and boiling point of 2300°C.
3. It can conduct electricity and heat easily
4. It has a high tensile strength and it is malleable and ductile.
5. It density should be about 8.95gcm-3
Uses of copper
1. It can turn into wires and cables for electricity as a result of it flexibility (ductile)
2. It can be used in the making of alloys
3. As a result of its attractiveness and resistance, copper can be used in plumbing and roofing of buildings.
4. It can also be used to produce ornaments
Past questions
1. Which of the following metals will be most suitable for use where lightness and resistance to corrosion are of importance? (Wassce 1996)
A. Lead
B. Copper
C. Iron
D. Calcium
E. Aluminum
Answer: E
2. The alloy used extensively in the building industry is? (Wassce 2004)
A. Steel
B. Bronze
C. Duralumin
D. Type metal
Answer: A
3. Metals can be stretched into wires because they are? (Wassce 2016)
A. Ductile
B. Good conductors
C. Lustrous
D. Malleable
Answer: A
4. Aluminum is used in the manufacture of aircraft because it? (Wassce 2016)
A. Is hard and brittle
B. Is light and resists corrosion
C. Has high density and conducts electricity
D. Is malleable and ductile
Answer: C
5. Which of the following is NOT involved in the extraction of metals from their ores?
(Jamb 1989)
A. Reduction with carbon
B. Reduction with other metals
C. Reduction by electrolysis
D. Oxidation with oxidizing agents
Answer: D
6. Which of the following metals will liberate hydrogen from steam or dilute acid? (Jamb 1990)
A. Copper
B. Iron
C. Lead
D. Mercury
Answer: B
7. The modern process of manufacturing steel from iron is by? (Jamb 2003)
A. Blast reduction
B. Treatment with acids
C. Treatment with Alkalis
D. Oxidation
Answer: A
8. Aluminium containers are frequently used to transport trioxonitrate v acid because aluminium? (Jamb 2013)
A. Does not corrode
B. Has a silvery-white appearance
C. Has a low density
D. Does not react with the acid
Answer: D
Ayagwa
•2 years ago
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