In this page, we are providing Synthetic Fibres and Plastics Class 8 Extra Questions and Answers Science Chapter 3 pdf download. NCERT Extra Questions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics with Answers will help to score more marks in your CBSE Board Exams.
Class 8 Science Chapter 3 Extra Questions and Answers Synthetic Fibres and Plastics
Extra Questions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics with Answers Solutions
Synthetic Fibres and Plastics Class 8 Extra Questions Very Short Answer Type
Name a natural fibre.
Name the basic component of animal fibres.
Name some artificial fibres.
Nylon, terylene, PET, acrylic, teflon, etc.
Which fibre is known as artificial silk?
In which country was rayon first time synthesised?
Name the first fully synthetic fibre.
Name the largest producer unit of rayon in the world.
Name a common variety of polyester.
What is ester?
Ester is sweet-smelling compound.
Name some objects made of plastics.
Containers, buckets, bottles, chairs, baskets, etc.
What is polythene?
Polythene is a polymer of ethene.
Give some examples of thermoplastics.
Polythene and polyvinyl chloride.
Give some examples of thermosetting plastics.
Bakelite and melamine.
What is the full form of PVC?
What is 4R’s?
4R’s stands for Redue, Reuse, Recycle and Recover.
Whether cotton cloth a biodegradable or non-biodegradable?
Name the form of polyester which is replacing materials like glass and used for making bottles and jars.
PET (Polyethylene Terephthalate)
Which of two is thermosetting plastic—PVC or bakelite?
Name a synthetic fibre which is polyamide.
Give the name of a plastic used for making fibres.
Synthetic Fibres and Plastics Class 8 Extra Questions Short Answer Type
What are polymers?
Polymers are compounds that are made up of same, small repeating units, joined together through bonds in a linear pattern.
What is cellulose?
Cellulose is a polymer made up of large number of glucose units.
List the two ways in which synthetic fibres can be synthesised.
Synthetic fibres may be synthesised by two ways:
- By regenerating them from natural fibres, like in rayon.
- By using entirely chemicals and chemical reactions, like in nylon.
What is rayon?
Rayon is a man-made fibre which is produced by the chemical processing of wood pulp, i.e., a natural substance.
List two uses of rayon.
The two uses of rayon are:
- It is used to make apparels like shirts, blouses, etc.
- It is used to make furnishings and upholstery.
List any two properties of rayon.
The two properties of rayon are:
- Rayon is a versatile fibre.
- It can be dyed in different colours.
Draw a diagram to show the:
(a) linear arrangement of units in plastic.
(b) cross-linked arrangement of units in plastic.
(b) Cross-linked arrangement
Write some advantages of synthetic fibres.
Advantages of synthetic fibres are:
- Synthetic fibres are strong and durable.
- They do not shrink.
- They are moth and insect resistant.
What are plastics?
Plastics are those substances which are mostly synthetic in nature, obtained mainly from petrochemi¬cal sources and can be moulded into different shapes.
What is plasticity?
Plasticity is the property of materials by which they can be moulded into any shape.
What are thermosetting plastics?
Thermosetting plastics are those which when moulded once, cannot be softened again and lose their plasticity.
List any three properties of plastics.
The three properties of plastics are:
- They are non-corrosive in nature.
- They are light in weight and durable.
- They do not conduct heat.
What are the uses of polyester?
The uses of polyester are:
- It is used in making home furnishings and apparels.
- Polyester is used for finishing on guitars and pianos.
Why is it advised not to wear synthetic clothes while working in a laboratory or working with fire in the kitchen?
The synthetic fibres melt on heating. This is actually a disadvantage with synthetic fibres. If the cloth catches fire it can be very disastrous. The fabric melts and sticks to the body of the person wearing it. It is therefore advised not to wear synthetic clothes while working in a laboratory or working with fire in the kitchen.
Write some properties and uses of melamine.
Melamine is a versatile material. It resists fire and can tolerate heat better than other plastics. It is used for making floor tiles, kitchenware and fabrics which resist fire.
Synthetic Fibres and Plastics Class 8 Extra Questions Long Answer Type
Describe about nylon. Write its uses and properties.
Nylon is the strongest amongst all the synthetic fibres. It is fully synthetic polymer which is prepared from coal, water and air. It is a polymer of amides. It was made in 1931 for the first time. It was used as a supplement of silk when silk got deficient during World War II for many military applications.
Uses of Nylon
- Nylon is used in toothbrushes, combs, etc.
- It is used to make parachutes, tents, ropes, etc.
- It is used to make socks and stockings as it is elastic.
- It is widely used for making clothes, carpets, etc.
Properties of Nylon
- It melts on heating.
- It absorbs less water.
- It is resistant to moths and fungi.
- It has high tensile strength.
- It is durable.
Write the advantages of synthetic fibres.
Synthetic fibres has many advantages as compared to natural fibres.
Some of them are as follows:
- They are very strong and durable.
- They are cheaper in cost as compared to natural fibres.
- They absorb less water and are quick to dry.
- They do not shrink.
- They are very useful for saving our trees and animals as they are made up of chemicals.
- They are moth and insect resistant.
List the common varieties of polyester. Also mention the natural fibres which are used for blending to enhance their properties.
Polyester could be blended with natural fibres to enhance its properties.
The common varieties of polyester are:
- PET (Polyethylene terephthalate)
- Terrycot: It is made by blending polyester and cotton.
- Terrysilk: It is made by blending polyester said silk.
- Terrywool: It is made by blending polyester and wool.
Explain the properties of plastics.
Plastics are those substances which are mostly synthetic in nature.
Following are the properties of plastics:
- Plastics are non-corrosive in nature, i.e., they do not react easily with air and water. They are unaffected by most of the chemicals in normal conditions.
- Plastics are the bad conductor of heat. They do not get heated up like metals.
- Plastics are non-biodegradable, i.e., they do not get decomposed by microorganisms.
- Plastics are very durable.
‘Plastics are hazard to environment’. Explain this statement.
Yes, plastics are hazard to environment. They make versatile materials but are very dangerous to the environment. Plastics are non-biodegradable in nature. It takes more than 100 years to decompose. If use of plastics are not reduced, our earth would turn into a big garbage bin.
The major problems due to plastics are:
- If plastics are burnt, they evolve poisonous gases. These gases destroys the ozone layer of the earth and also pollute the environment.
- If the plastics are disposed in drains, they choke the drains causing waterlogging.
- If these plastics are swallowed by the innocent animals along with their food, they harm their di-gestive system which leads to their death.
- They are manufactured by the consumption of a large amount of petroleum.
List the strategies for plastic waste management.
Some of the strategies for plastic waste management are:
- We should use paper bags and jute bags instead of using plastic bags.
- The government should ban the use of plastic bags.
- Plastics should be recycled to make other useful products which do not harm the environment.
- We should use a special garbage bins to dispose plastic wastes.
- We should not throw plastic wastes in water bodies.
- Practicing 4R’s principle, i.e., Reuse, Recycle, Reduce and Recover should be encouraged.
Synthetic Fibres and Plastics Class 8 Extra Questions HOTS
Cotton is a natural polymer. What is its chemical name?
Why plastic items are available in all possible shapes and sizes?
Plastics can be moulded to any shape. So they are available in all possible shapes and sizes.
What nature of plastics makes them a good storage containers for most of the articles?
Plastics are non-reactive.
A lady went to the market to buy a blanket. The shopkeeper showed her blankets made of acrylic fibres as well as made of wool. She preferred to buy an acrylic blanket. Can you guess why?
Blanket made of acrylic is cheap, durable, light in weight, available in variety of colours and provide the same warmth as that of wool.
Is using plastics for storing food safe?
Though storing and carrying food in plastic container is more efficient. But chemicals used for manufacturing plastics leeches out into the food and contaminates it. Though it is in very small amount but continuous use of it is exposing our body to harmful and poisonous chemicals.
Synthetic Fibres and Plastics Class 8 Extra Questions Value Based (VBQs)
Riya’s father got a transfer to another place. While sorting out the things Riya found many of her clothes of various fabrics were not fitting her or worn out. She thought of burning them to get rid of them. But her friend Shweta suggested to donate it to some charity house so that it can be reused.
(a) What are the two main types of fibres?
(b) Which fabrics are known to be skin friendly? Why?
(c) Why we should not burn synthetic clothes?
(d) Why synthetic clothes are famous than natural fabrics?
(e) What values of Riya and Shweta are shown here?
(a) Two main types of fibres are natural and man-made fibres.
(b) Natural fabrics are known to be skin friendly because they absorb moisture and do not contain chemicals as that of synthetic fibres which may cause skin irritation.
(c) Synthetic clothes emits poisonous gases on burning.
(d) Synthetic clothes are famous than natural clothes because they are light, durable, cheaper, easy to maintain, moth resistant and available in various colours.
(e) Riya is ignorant and non-ecofriendly whereas Shweta is insightful and eco-friendly.
Piku is very fond of art and craft. She decided to make some items like pen keeper, purses, toys, etc., using old fabrics and plastics. She donated these in a charity.
(a) Is it practical to say completely ‘NO’ to plastics?
(b) How can we reuse any plastic items?
(c) What value of Piku is shown here?
(a) No, it is not at all practical to say completely ‘NO’ to plastics because nowadays plastics are insepa-rable part of our daily life.
(b) We can reuse plastic bags for storing dry things. We can reuse plastic bottles for storing dry food grains or a pen keeper, etc.
(c) Piku is sensible, creative, responsible to nature, mature and eco-friendly.