Class 10 Chemistry Chapter 8 Notes

Complete Notes of Chapter No. 16: Chemical Industries Class 10 or class 10 chemistry chapter 8 notes by Mr. Tasneem Haider. These computerized notes are very helpful in the preparation of class 10 chemistry chapter 8 notes for students of Chemistry and these are according to the paper patterns of all Punjab boards.

• Important Multiple Choice Questions (MCQs) of Chapter No. 16: Chemical Industries for Chemistry Urdu Medium 10th Class.
• Important Short Questions of Chapter No. 16: Chemical Industries for Chemistry Urdu Medium 10th Class.
• Introduction: Chemical industries are established to meet the needs of modern societies. Metallurgy is the science of extracting metals from ores. Metals have played a major role in progress of societies. Since ages metals are used for making tools, machines and other items. In the modern age, although polymers have taken the place of metals, yet the importance of metals cannot be ignored. Baking soda (NaHCO3 ) and washing soda (Na2CO3 ) are used in daily life for different purposes. Solvay’s process for the manufacturing of baking and washing soda from common salt will be discussed in detail. 
• Minerals: The solid natural materials found beneath the Earth’s surface, which contains compounds of metals in the combined state along with earthly impurities, are called minerals.
• Ores: Those minerals from which the metals are extracted commercially at a comparatively low cost with minimum effort are called ores of the metals. For example: ores of copper are; copper glance (Cu2S) and chalcopyrite (CuFeS2). Hence, all ores of the metals are minerals, but all minerals are not ores.
• Gangue: The earthly and other impurities associated with the minerals are known as gangue.
• Metallurgy: The process of extraction of a metal in a pure state on a large scale from its ore by physical or chemical means is called metallurgy.
• The processes involved in metallurgy for extraction of a metal in the pure state from its ore are: (i) concentration of the ore; (ii) extraction of the metal, and (iii) refining of the metal.
• (i) Concentration of the Ore: The process of removal of gangue from the ore is technically known as concentration and the purified ore is called the concentrate. Concentration of the crushed ore is carried out by the following methods:
• (a) Gravity separation: Gravity separation is based on the differences in densities of the metallic ore and the gangue particles. In the process, the powdered heavy metal bearing ore settles down on agitation in a stream of water, while the lighter gangue particles are carried away by the water.
• (b) Froth flotation process: Froth flotation process is based on the wetting characteristic of the ore and the gangue particles with oil and water, respectively. The ore particles are preferentially wetted by oil and the gangue particles by water. The whole mixture is agitated with compressed air. Hence, oil coated ore particles being lighter come to the surface in the form of froth that can be skimmed.
• (c) Electromagnetic separation: Electromagnetic separation is based on the separation of magnetic ores from the non-magnetic impurities by means of electromagnets or magnetic separators. The powdered ore is dropped over a leather belt moving over two rollers, one of which is magnetic. The non-magnetic ore falls first and the magnetic ore gets attracted and falls farther away.
• (ii) Extraction of the metal from the concentrated ore: The metal is isolated from the concentrated ore by chemical reduction or electrolytic processes. Chemical methods of reduction of ore involve following methods: (a) Roasting,   (b) Smelting,   (c) Bassemerization
• (a) Roasting: It is a process of heating the concentrated ore to a high temperature in excess of air. For example; copper pyrite (CuFeS2) is strongly heated in excess of air to convert it into a mixture of cuprous sulphide and ferrous sulphide (Cu2S + FeS), while impurities react with oxygen to form 2 volatile oxides.