CLASS 6 _ INTRODUCTION To CHEMISTRY

https://www.youtube.com/watch?v=z3Gt5IOjAuc&list=PLaLOVNqqD-2FZMjQfGiFGlFWZEhN_qRJK

https://www.youtube.com/watch?v=wbuDmY5gpXQ&list=PLaLOVNqqD-2FZMjQfGiFGlFWZEhN_qRJK&index=2

https://www.youtube.com/watch?v=GWQZE0HPoAY&list=PLaLOVNqqD-2FZMjQfGiFGlFWZEhN_qRJK&index=3

2. INDIA'S ANCIENT SCIENCE
https://www.youtube.com/watch?v=_fEBWkowuDI

3. Documentary on Acharya Prafulla Chandra Roy
https://www.youtube.com/watch?v=d3v-8Ga8LkA

https://www.youtube.com/watch?v=pKyPrfio59o

4. Map of Chemistry

5. Alchemy


 1. Chemistry and its Importance.

Chemistry is that branch of science that deals the study of substances and materials. Chemistry plays a crucial role in many areas. It is through chemical means that some products are synthesised and manufactured and end products are obtained.
Can you just think of one example which is manmade and widely used?
The answer is plastic.
The knowledge of chemistry can be applied to change the nature of the existing material or to create new products. In this chapter, you will learn about the importance and applications of chemistry in various fields.
All our activities depend upon our knowledge of chemistry. All everyday articles we use such as plastics, clothes, detergents, toothpaste are all derived by knowledge of the composition of compounds. Several industries are dependent on chemistry and its applications.
§  Role in Agriculture: Fertilisers, fungicides, weedicides, insecticides and pesticides have helped farmers to improve crop yield by preventing destruction of crops bypests and insects.
§  Role in Metallurgy: Different methods of extracting metal from ores are obtained by a knowledge of chemistry. Metals are the backbone of our economy and help in the country’s growth and development.
§  Role in Petrochemical industry: The separation of several important compounds from crude oil are done by chemical techniques. Petrol, diesel, LPG, kerosene, paraffin wax are all obtained from crude oil.
§  Role in Industry: Drugs, dyes, explosives, paints, plastics, synthetic fibres such as polyester and nylon, alloys and textiles have been manufactured with knowledge of chemistry.
§  Role in Medicine: Chemists have researched and discovered drugs to cure diseases such as malaria, TB. antibiotics like penicillin, tetracycline, garramycin have been used to kill bacteria and cure infections. Drugs have been used to control BP, heart diseases and even cancer. Painkillers and antipyretic drugs (to control fever) are also developed by chemists.
§  Role in Daily Life through Consumer Products: Toothpastes, soaps, detergents, glass, dyes, pens, pencils and paper which we use everyday are all made with the help of chemistry.
§  Role in Construction Industry:R Chemical processes are used to make cement, mortar, bricks, glass, paints, varnish and other materials used to build bridges, houses, roads and industries
§  Role in Transport: We obtain fuel used to drive cars, scooters and other modes of transport by chemical processes.
§  Role in Communication: Chemicals, wires, chips, plastics used to make mobiles, phones, TVs and radios are all obtained by chemical processes.
§  Role in Defence: Explosives like TNT, grenades, gunpowder are also obtained by chemical methods.
§  Role in Sports: Sports goods are made of rubber, plastic, nylon, rubber ad leather all of which are derived by chemical means from different compounds.
§  Role in Energy Crisis: Chemists are developing alternate sources of energy like solar energy, geothermal energy, nuclear energy and ocean thermal energy to prevent disappearance of reserves of coal and petrol. Fuels burned to give light and heat energy are all discoveries of chemistry. E.g. solid fuel like charcoal, liquid fuel like diesel and petrol and gaseous fuel like natural gas.
§  Our body uses several chemicals like enzymes and hormones to carry out metabolic activities. hydrochloric acid is present in our stomach to help digestion of food.
§  Carbohydrates, fats, proteins, vitamins are all nutrients important to life and are all chemical compounds.

However, chemicals can also cause damage:
§  Pollutants are harmful substances released into the environment that can cause safety and health hazards.
§  Atom bombs and other nuclear weapons have been used in mass destruction.
§  Harmful drugs like LSD and cocaine have harmed many people because of addiction.

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INTRODUCTION TO CHEMISTRY

EXERCISE
1.      What is Chemistry?
Ans. The branch of science which deals with the study of the composition and the physical and chemical properties of various forms of matter.

2.      Give 2 examples for each of the following substances:
a.       Food preservative
b.      Fuel
c.       Fungicides
d.      Medicines
e.       Building materials
f.       Chemical war weapons
g.      Fertilizers
h.      Natural Fibre

          Ans:
a.       Food preservative – Salt, Mustard oil
b.      Fuel                       – Coal, Petrol
c.       Fungicides            - Sulphur, Bordeaux mixture
d.      Medicines              - Aspirin, Paracetamol
e.       Building materials – Cement, Sand
f.       Chemical war weapons – Gunpowder, T.N.T.
g.      Fertilizers             - Urea, Potash
h.      Natural Fibre        - Cotton, silk
           
3.      What is a fuel?
Ans.: Fuels are substances which on combustion produce large amount of heat energy.






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