Metal and Non-Metal
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Unit 17.
Metal and Non-metal.
Exercise:
2) Give reason:
(a) All ores are minerals but all minerals are not ores.
Answer: All ore are mineral because it’s natural occuring and has a definite composition. But not all minerals are ores because many minerals don’t have enough metal to extract profitably.
(b) ores are oxidised after concentration.
Answer: ores are oxidised after concentration because it is easier to extract metals from their oxides.
3) Difference between:
(a) Minerals and Ores
| Minerals | Ores |
|---|---|
| The elements and compounds which are found naturally are called minerals. | The minerals from which metals are extracted are called ores. |
| They are obtained from earth’s crust. | ores are obtained from minerals. |
(b) Roasting and Calcination
| Roasting | Calcination |
|---|---|
| The process of strongly heating the ores to their oxides by passing air or in presence of oxygen is called roasting. | The process of strongly heating the ore to their oxides in the absence of air or without passing oxygen is called calcination. |
| Roasting is done to convert sulphide ores to their oxide ores. | calcination is done to convert carbonate ores to their oxides. |
(c) Oxidation and Reduction
| Oxidation | Reduction |
|---|---|
| It is a process of changing concentration ores to metal ores. | It is the process of removing oxygen from their metal. |
| There are two process of oxidation. | There is only one process for reduction. |
4) Answer Question.
(a) What are the source of metals.
Answer: Ores are the source of metals.
(b) How is metallurgy a stepwise process?
Answer: metallurgy is the science and technology of extracting metals from their ores and refining them for use, involving a series of sequential steps. The general steps include:
(i) Grinding:
The process of crushing ores into the small fine particles using the machine roles is known as grinding.
(ii) Concentration:
Concentration is the process of removing impurities from the crushed ores.
(iii) Oxidation:
This is the process of converting ores or other metals into their oxides in the presence or absence of oxygen.
(iv) Reduction:
It is the process of removing oxides from the metal oxides.
(v) Refining:
The metals obtained after the Reduction may still contain some impurities so to obtain metals in pure state refining is done.
(c) make a list of ores of iron, copper, aluminium and silver.
Iron: Haematite (Fe2O3), magnetite (Fe3O4), Siderite.
Copper: Chalcopyrite (CuFeS2), Bornite (Cu5FeS4), Cuprite (Cu2O).
Aluminium: Bauxite (Al2O3·2H2O), cryolite (Na3AlF6).
Silver: Argentite (Ag2S), Horn silver (AgCl).
(d) How pure metals are obtained from electro-refining? Explain with an activity.
Answer:
Activity:
purifying impure copper by the method of electro-refining.
materials required:
voltameter, impure copper, pure copper plate, battery, copper-sulphate solution, or solution of any copper salts.
method:
Take the solution of copper sulphate in the voltameter. Connect impure copper to the positive terminal of the battery and the pure copper plate to the negative terminal of the battery. Thus by making copper an anode and pure copper as cathode. Now pass electricity into voltameter.
Observation:
The impure copper plate in anode erodes and pure copper gets deposited on the cathode.
Conclusion:
In this way, we can get the pure copper from its impure form by the process of electrolysis.
Discussion
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