Frank Cce Everyday Science Solutions for Class 8 Science Chapter 3 Synthetic Fibres And Plastics are provided here with simple step-by-step explanations. These solutions for Synthetic Fibres And Plastics are extremely popular among Class 8 students for Science Synthetic Fibres And Plastics Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Frank Cce Everyday Science Book of Class 8 Science Chapter 3 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Frank Cce Everyday Science Solutions. All Frank Cce Everyday Science Solutions for class Class 8 Science are prepared by experts and are 100% accurate.

Page No 49:

Question A:

Answer:



Page No 50:

Question B.1:

Answer:

(c) Teflon

Teflon is used for making non-stick pans.

Page No 50:

Question B.2:

(c) Teflon

Teflon is used for making non-stick pans.

Answer:

(a) Perspex

This is used as a substitute for glass because it is transparent and unbreakable.

Page No 50:

Question B.3:

(a) Perspex

This is used as a substitute for glass because it is transparent and unbreakable.

Answer:

(a) Plastics

Plastic is a poor conductor of electricity.

Page No 50:

Question B.4:

(a) Plastics

Plastic is a poor conductor of electricity.

Answer:

(b) jute

Jute is a natural fibre obtained from plants.

Page No 50:

Question B.5:

(b) jute

Jute is a natural fibre obtained from plants.

Answer:

 (d) Polythene

Polythene is highly inflammable.

Page No 50:

Question B.6:

 (d) Polythene

Polythene is highly inflammable.

Answer:

(a) Polystyrene

Thermocol is obtained from polystyrene.

Page No 50:

Question B.7:

(a) Polystyrene

Thermocol is obtained from polystyrene.

Answer:

(a) Polyester

Polythene tetraphthalate (PET) is a very popular form of polyester.

Page No 50:

Question B.8:

(a) Polyester

Polythene tetraphthalate (PET) is a very popular form of polyester.

Answer:

(a) Nylon

Nylon is the first synthetic fibre produced. It was made by an American chemist, W.H. Carothers in the year, 1935.

Page No 50:

Question B.9:

(a) Nylon

Nylon is the first synthetic fibre produced. It was made by an American chemist, W.H. Carothers in the year, 1935.

Answer:

(a) Teflon

Non-stick utensils are coated with teflon.

Page No 50:

Question B.10:

(a) Teflon

Non-stick utensils are coated with teflon.

Answer:

(a) Thermosetting polymer

Melamine is an example of a thermosetting polymer.

Page No 50:

Question C:

(a) Thermosetting polymer

Melamine is an example of a thermosetting polymer.

Answer:

1. PVC is the short form of polyvinyl chloride.
2. Teflon is used for making non-stick cookware.
3. Plastics are synthetic material.
4. A material that can be decomposed by natural processes is called a natural material.
5. Bakelite is a thermosetting plastic.

Page No 50:

Question D:

1. PVC is the short form of polyvinyl chloride.
2. Teflon is used for making non-stick cookware.
3. Plastics are synthetic material.
4. A material that can be decomposed by natural processes is called a natural material.
5. Bakelite is a thermosetting plastic.

Answer:

Column A Column B
1. Rayon (e) Bandages
2. Nylon (d) Tooth brush
3. Melamine (a) Unbreakable kitchen ware
4. Teflon (b) Non-stick pans
5. Bakelite (c) Handle of saucepan

Page No 50:

Question E:

Column A Column B
1. Rayon (e) Bandages
2. Nylon (d) Tooth brush
3. Melamine (a) Unbreakable kitchen ware
4. Teflon (b) Non-stick pans
5. Bakelite (c) Handle of saucepan

Answer:

1. False
Polyester does not shrink on washing.

2. False
 Plastics are sensitive towards heat and they melt very fast on heating.


3. False
Acrilon fibre is obtained from the acrylonitrile monomer by the process of polymerisation.

4. True

5. False
PVC is an insulator and is used as a covering for electrical wiring.



Page No 51:

Question A.1:

1. False
Polyester does not shrink on washing.

2. False
 Plastics are sensitive towards heat and they melt very fast on heating.


3. False
Acrilon fibre is obtained from the acrylonitrile monomer by the process of polymerisation.

4. True

5. False
PVC is an insulator and is used as a covering for electrical wiring.

Answer:

Following are two synthetic fibres:
i) Polyester
ii) Polyethylene

Page No 51:

Question A.2:

Following are two synthetic fibres:
i) Polyester
ii) Polyethylene

Answer:

Rayon is called artificial silk because it has a similar appearance, shine and texture as that of silk. It is prepared from cellulose of wood pulp.

Page No 51:

Question A.3:

Rayon is called artificial silk because it has a similar appearance, shine and texture as that of silk. It is prepared from cellulose of wood pulp.

Answer:

The following are two properties of a nylon fibre:
i) It is very strong and fairly elastic.
ii) It absorbs very little water; hence, it dries up rapidly.

Page No 51:

Question A.4:

The following are two properties of a nylon fibre:
i) It is very strong and fairly elastic.
ii) It absorbs very little water; hence, it dries up rapidly.

Answer:

Perspex can be used as a substitute for glass.

Page No 51:

Question A.5:

Perspex can be used as a substitute for glass.

Answer:

Teflon is used to make non-stick cookware.

Page No 51:

Question A.6:

Teflon is used to make non-stick cookware.

Answer:

W.H. Carothers (1935) made the first synthetic fibre (nylon).

Page No 51:

Question A.7:

W.H. Carothers (1935) made the first synthetic fibre (nylon).

Answer:

The following are two natural fibres:
i) Cotton
ii) Jute

Page No 51:

Question A.8:

The following are two natural fibres:
i) Cotton
ii) Jute

Answer:

Acrylic resembles wool in its properties.

Page No 51:

Question A.9:

Acrylic resembles wool in its properties.

Answer:

PVC (polyvinyl chloride) is used to make raincoats.

Page No 51:

Question A.10:

PVC (polyvinyl chloride) is used to make raincoats.

Answer:

The 4 Rs that should be practised to minimise environmental pollution are reduce, reuse, recycle and recover.



Page No 52:

Question B.1:

The 4 Rs that should be practised to minimise environmental pollution are reduce, reuse, recycle and recover.

Answer:

Polymers are a long chains of small units called monomers that are joined together by the process of polymerisation.
Example: rayon, nylon etc.

Page No 52:

Question B.2:

Polymers are a long chains of small units called monomers that are joined together by the process of polymerisation.
Example: rayon, nylon etc.

Answer:

Polymerisation is the process through which a large number of monomers are linked together to form a polymer.

n Monomers   Polymerisation   Polymer

 

Page No 52:

Question B.3:

Polymerisation is the process through which a large number of monomers are linked together to form a polymer.

n Monomers   Polymerisation   Polymer

 

Answer:

The following are two types of plastic:
i) Thermoplastics: Examples are polythene, polystyrene and PVC.
ii) Thermosetting plastics: Examples are bakelite and melamine.

Page No 52:

Question B.4:

The following are two types of plastic:
i) Thermoplastics: Examples are polythene, polystyrene and PVC.
ii) Thermosetting plastics: Examples are bakelite and melamine.

Answer:

Synthetic fibres are superior to natural fibres in the following aspects:
1. Synthetic fibres are strong and cheaper, whereas natural fibres are not.
2. Synthetic fibres are crease-resistant, whereas natural fibres are not.
3. Synthetic fibres are not attacked by moths and moulds, whereas natural fibres can be easily destroyed by them.
4. Synthetic fibres are light and durable but natural fibres are not durable.

Page No 52:

Question B.5:

Synthetic fibres are superior to natural fibres in the following aspects:
1. Synthetic fibres are strong and cheaper, whereas natural fibres are not.
2. Synthetic fibres are crease-resistant, whereas natural fibres are not.
3. Synthetic fibres are not attacked by moths and moulds, whereas natural fibres can be easily destroyed by them.
4. Synthetic fibres are light and durable but natural fibres are not durable.

Answer:

The following are the two uses of PVC (polyvinyl chloride):
(i) It is used as an insulating covering for electrical wires.
(ii) It is used in making hand bags, raincoats, floor-covering materials and suitcase covers.

Page No 52:

Question B.6:

The following are the two uses of PVC (polyvinyl chloride):
(i) It is used as an insulating covering for electrical wires.
(ii) It is used in making hand bags, raincoats, floor-covering materials and suitcase covers.

Answer:

The following are the advantages of synthetic fibres over natural fibres:

i) They are strong and cheaper.
ii) They are crease-resistant.
iii) They are not attacked by moths and moulds.
iv) They are hydrophobic; hence, they dry quickly.
v) They are light and durable.

Page No 52:

Question B.7:

The following are the advantages of synthetic fibres over natural fibres:

i) They are strong and cheaper.
ii) They are crease-resistant.
iii) They are not attacked by moths and moulds.
iv) They are hydrophobic; hence, they dry quickly.
v) They are light and durable.

Answer:

The following are three qualities of polyesters:
i) Polyesters are strong and wrinkle-resistant.
ii) They absorb very little water; hence, they dry quickly.
iii) They are resistant to the action of chemicals.

Page No 52:

Question B.8:

The following are three qualities of polyesters:
i) Polyesters are strong and wrinkle-resistant.
ii) They absorb very little water; hence, they dry quickly.
iii) They are resistant to the action of chemicals.

Answer:

Bakelite and melamine are two thermosetting plastics.

Page No 52:

Question B.9:

Bakelite and melamine are two thermosetting plastics.

Answer:

Non-biodegradable materials are those materials that are not degraded naturally or by the actions of microorganisms. Example: plastic

Page No 52:

Question B.10:

Non-biodegradable materials are those materials that are not degraded naturally or by the actions of microorganisms. Example: plastic

Answer:

Synthetic clothes are not suitable in summer because air does not pass freely through such clothes. Also, they do not absorb sweat as clothes made up of natural fibres like cotton do.

Page No 52:

Question C.1:

Synthetic clothes are not suitable in summer because air does not pass freely through such clothes. Also, they do not absorb sweat as clothes made up of natural fibres like cotton do.

Answer:

Synthetic fibres are those fibres that are made artificially, using chemicals. The general process used to obtain synthetic fibres is polymerisation. It is a process in which small units (monomers) are joined together to form a polymer.

General reaction:
n MonomerPolymerisation   Polymer

Examples of synthetic fibres: nylon, rayon and polyester

Page No 52:

Question C.2:

Synthetic fibres are those fibres that are made artificially, using chemicals. The general process used to obtain synthetic fibres is polymerisation. It is a process in which small units (monomers) are joined together to form a polymer.

General reaction:
n MonomerPolymerisation   Polymer

Examples of synthetic fibres: nylon, rayon and polyester

Answer:

The following are four advantages of synthetic fibres:

1. Synthetic fibres are strong and cheaper. Example: Polyester and nylon are strong and comparatively cheaper than natural fibres such as cotton.

2. Synthetic fibres do not retain creases. Example: Both nylon and polyester are resistant to wrinkles.

3. Synthetic fibres are resistant to the attacks of moths and moulds. Example: Nylon and acrylic resist the attack of moths, moulds and other insects.

4. Synthetic fibres are light, durable and easy to maintain. Examples: Nylon, acrylic and polyester are light, durable, washable and easy to maintain.

Page No 52:

Question C.3:

The following are four advantages of synthetic fibres:

1. Synthetic fibres are strong and cheaper. Example: Polyester and nylon are strong and comparatively cheaper than natural fibres such as cotton.

2. Synthetic fibres do not retain creases. Example: Both nylon and polyester are resistant to wrinkles.

3. Synthetic fibres are resistant to the attacks of moths and moulds. Example: Nylon and acrylic resist the attack of moths, moulds and other insects.

4. Synthetic fibres are light, durable and easy to maintain. Examples: Nylon, acrylic and polyester are light, durable, washable and easy to maintain.

Answer:

Thermoplastics are plastic substances that can be melted by heating. They can be moulded again and again by heating and can be given different shapes. Examples of thermoplastics: polythene and polyvinyl chloride

Uses of thermoplastics:
i) Polythene is used for making waterproof material.
ii) PVC is used as an insulating covering for electrical wiring.

Thermosetting plastics are a type of plastic, which can be moulded only once. They do not soften on heating. Softening and moulding are irreversible characteristics of thermosetting plastics. Examples of thermosetting plastics: bakelite and melamine

Uses of thermosetting plastics:
i) Bakelite is used for making plugs, switches, telephone cases and other electrical fittings.
ii) Melamine is used for making unbreakable dinner ware and decoration pieces.

Page No 52:

Question C.4:

Thermoplastics are plastic substances that can be melted by heating. They can be moulded again and again by heating and can be given different shapes. Examples of thermoplastics: polythene and polyvinyl chloride

Uses of thermoplastics:
i) Polythene is used for making waterproof material.
ii) PVC is used as an insulating covering for electrical wiring.

Thermosetting plastics are a type of plastic, which can be moulded only once. They do not soften on heating. Softening and moulding are irreversible characteristics of thermosetting plastics. Examples of thermosetting plastics: bakelite and melamine

Uses of thermosetting plastics:
i) Bakelite is used for making plugs, switches, telephone cases and other electrical fittings.
ii) Melamine is used for making unbreakable dinner ware and decoration pieces.

Answer:

Plastics are considered environmental hazards because they are usually non-biodegradable, which means that they do not get decomposed by microbes into simpler compounds. Some of the problems caused by the excessive use of plastics are as follows:
1. Plastic bags block the drains and cause the overflowing of waste water. Blocked drains are a breeding place for mosquitoes.
2. Sometimes animals eat discarded plastic bags along with garbage, which leads to their death.
3. Recycled plastic used as containers for food causes health hazards.
4. Burning of plastic causes air pollution.

Page No 52:

Question C.5:

Plastics are considered environmental hazards because they are usually non-biodegradable, which means that they do not get decomposed by microbes into simpler compounds. Some of the problems caused by the excessive use of plastics are as follows:
1. Plastic bags block the drains and cause the overflowing of waste water. Blocked drains are a breeding place for mosquitoes.
2. Sometimes animals eat discarded plastic bags along with garbage, which leads to their death.
3. Recycled plastic used as containers for food causes health hazards.
4. Burning of plastic causes air pollution.

Answer:

Following are the steps to reduce the dangers of plastic pollution:

1. The use of plastic bags and other items made of plastic should be reduced.
2. For shopping, we can carry our own cloth bags or jute bags.
3. Anything made of plastic should not be burnt.
4. Reuse plastic bags by keeping them clean.
5. Practise and follow the 4-R principle of reduce, reuse, recycle and recover to minimise environmental pollution.

Page No 52:

Question C.6:

Following are the steps to reduce the dangers of plastic pollution:

1. The use of plastic bags and other items made of plastic should be reduced.
2. For shopping, we can carry our own cloth bags or jute bags.
3. Anything made of plastic should not be burnt.
4. Reuse plastic bags by keeping them clean.
5. Practise and follow the 4-R principle of reduce, reuse, recycle and recover to minimise environmental pollution.

Answer:

Biodegradable Materials Non-biodegradable Materials
Biodegradable materials are decomposed naturally in the environment. Non-biodegradable materials are not decomposed naturally.
They are present only for a small time in the environment. They are present for a longer time in the environment.
They do not cause much environmental hazard      . They cause considerable environmental hazards.
Example: waste paper and wood crumbs. Example: plastic bags and cans.



View NCERT Solutions for all chapters of Class 8