Kerala SCERT Class 8 Basic Science Chapter 17 Fibres and Plastics Question Answer Solution Here. Kerala Board Class 8 Students can find Here 17th Chapter Fibres and Plastics Notes provide by our Teacher. Important Question Answer from Chapter 17 Fibres and Plastics.
- Board- Kerala Board.
- Class – 8.
- Subject – Basic Science Part 2
- Chapter – 17.
- Chapter Name – Fibres and Plastics.
- Topic – Question Answer Solution.
Answer the following in one sentence.
1.) What is polymer?
Ans- the substances like fibre, clothes, silk, wool, cotton etc are made from the molecules are known as polymer. Polymers are the micro molecules formed by the combination of large number of simple molecules(monomers).
2.) Define
a.) Biopolymer- the proteins, DNA, starch, cellulose etc are found in living being belongs to the polymer category called biopolymer.
b.) Natural polymer- the polymer which are obtained from nature are known as natural polymer. The silk and cotton are natural polymers.
c.) Synthetic polymer-the polymer which are not obtained in nature are called synthetic or man-made polymer. Polymers like nylon, rayon, polythene and PVC made in science laboratory belong to the category are called synthetic polymer.
3.) Give difference between-
a.) Rubber and plastic
Ans-
Rubber | Plastic |
Rubber is the natural polymer with having elastic property. | Plastic are the polymers which having different properties from other polymers. |
Rubber is isolated from the latex, obtained from rubber tree. | Plastic are synthetic polymers or man made polymers. |
Rubber is formed by combination of the monomer molecules isoprene.
Example- Buna S, Buna N etc |
Different types of plastic are used for manufacturing a no of products form household utensils to artificial heart valves. |
b.) Nylon and rayon
Nylon | Rayon |
Nylon is the first artificial prepared fiber. | Rayon is a semi synthetic fiber known as artificial fiber. |
Nylon got its name from the cities, New York and London. | Rayon having similar properties of natural silk . |
The different types of nylons are there like nylon 6, nylon 6-6 etc | Rayon is mostly used for the manufacturing of silk clothes. |
The material like rope, clothes, fabric are made from nylon. | Soft silk, silk , soft cotton are usually made from rayon. |
4.) What ate the 4R’s?
Ans- the 4R’s are use of plastics to the maximum extent as well as to avoid the pollution caused by plastic.
REDUCE – plastic
REUSE- plastic
REFUSE- plastic
RECYLCE – plastic
Answer the following in short.
1.) Difference between thermoplastic and thermosettings polymer.
Ans-
Thermoplastic | Thermosetting plastic |
The plastic which get softened on heating and hardened on cooling is called thermoplastic polymer. | The plastic which remains soft when heated during its manufacturing and gets hardened on cooling is called thermosetting plastic. |
The thermoplastic process can be repeated number of times. | The thermosetting plastic once hardened they cannot be remoulded by heating. |
Thermoplastic undergo physical change on heating. | Thermosetting plastics on heating undergo chemical change along with physical change. |
Example of thermoplastic are polythene, poly vinyl chloride. | Example of thermosetting plastic are bakelite, melamine. |
2.) Explain the different types of plastics.
Ans- plastics are polymers having properties different from those of fibers. These are substances that changed the very face of human life. Plastics are synthetic polymers. There are different types of plastics are used for manufacturing a number of products from household utensils to artificial heart valves.
There are different types of plastics have different molecular structure. Thermoplastic are called linear polymers. These are formed by the linear combination of monomers. Thermosetting plastics have a structure in which the monomer units are cross linked in different directions.
The structural difference between these two is the reason for their difference in behaviour towards heat. These are the two Thermosetting and thermoplastic are the two types of plastics.
3.) Explain man -made fibers.
Ans- as we know there are natural polymers and man made polymers. Natural polymers are obtained from the nature and the polymer which are made by man or artificially are called synthetic polymer or man made polymer.
The synthetic polymers are prepared by chemical method. Synthetic fibers are generally used by blending them with natural substances like cotton. The examples of this fibers are nylon, terylene which are mostly used in textile industry. This fibers are cheaper than natural fibers, have high durability, wrinkle free and can get easily wet and dry. This are the some characters of man made fibers.
Answer the following in brief.
1.) Give example of Thermoplastic polymer and their uses.
Ans- thermoplastic are the polymer that gets softened on heating and hardened on cooling.
There are some example and their uses of thermoplastic polymers-
Polythene- for the manufacture of different packets, tubes , containers etc.
Poly vinyl chloride (PVC)- for the manufacturing of electrical wirings, plumbing, shoes, hand bags, raincoats, bottles, furniture etc.
2.) Give example of Thermosetting polymers and their uses.
Ans- the plastic which remain soft when heated during its manufacture and gets hardened permanatly on cooling is called thermosetting polymers.
There are some examples and their uses as following-
Bakelite- for the manufacture of plugs , switches , buttons, handles of electrical utensils and kitches.
Melamine – formal dehyde resin- for the manufacture of unbreakable crockery.
3.) Write note on pollution due to plastic.
Ans- as we know plastic are the synthetic polymer . there are different types of plastic are present like thermosetting and thermoplastic . now days plastic are used in various manufacturing units for making households utensils, other materials etc. For making plastic chemical substances are used so they are harmful for the environment. So due to this harmfulness the use of plastic are banned in a number of places. Also there are some steps have been taken to make hospitals , campuses, zoos and public places plastic free. This things are do because plastic do not undergo bio- degradation like other substances. Due to this it is very dangerous to animals like cow, dog if they eat food with plastic. Therefore you have to avoid the use of plastic or try to use less plastic instead of this try to use other things which can replace plastic like use paper bags, clothes bags.
Avoid disposable plastic products. Used plant materials for decoration instead of plastic.
This are some things we can do for avoid plastic pollution and there harm.
4.) Draw Recycling Symbols.
Ans- for effective plastic recycling it is neceesary to identify the type of a particular plastic. Different plastic have been given certain recycling symbols. Triangular arrows with numbers from 1 to 7 printed on them are used symbols.
The symbols like following-
MCQ
1) The thickness of plastic is expressed in—-
a) Microns
b) Miligrams
c) Nanograms
d) Micrograms
Ans- a) microns
2) Bakelite is the example of—–
a) Thermoplastic
b) Thermosetting
c) Rubber
d) Rayon
Ans- b)themosetting
3) The thermoplastic are also called—-
A) Thermiosetting polymer
B) Linear polymer
C) Branched polymer
D) Star polymer
Ans- b) linear polymer
Kerala SCERT Class 8 Science Fibres and Plastics Question Answer
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