Loading....
Coupon Accepted Successfully!

 

Question 1

What is polymer?

Solution:
it is a chain of small units (monomers) joined together

 

Question 2

Name some natural fibres

Solution:
Cotton, wool, silk etc

 

Solution:

Nylon, terylene, Teflon, PET (polyethylene terepthalate), acrylic

 

Solution:

Cellulose is a polymer made up of large number of glucose units
 

Question 6

Name the first fully synthetic fibre

Solution:
Nylon

 

Question 7

What is the raw material used for making synthetic fibres?

Solution:
All synthetic fibres are prepared from raw materials of petroleum origin called petrochemicals

 

Question 8

Name any two thermoplastics

Solution:
Polythene and PVC

 

Question 9

Name any two thermosetting plastics

Solution:
Bakelite and melamine

 

Question 10

Write two important properties of bakelite

Solution:
It is a poor conductor of electricity, it is heat resistant

 

Question 11

What is rayon? Write its some uses

Solution:
Rayon is obtained from a natural source, wood pulp, it is a man-made fibre it is cheaper than silk, but can be woven like silk fibres. It can also be dyed in a wide variety of colours. Rayon is mixed with cotton to make bed sheets or mixed with wool to make carpets.

 

Picture of articles made of rayon

Question 12

Write the properties and uses of nylon

Solution:
Nylon fibre is strong. elastic and light it is lustrous and easy to wash. So, it is very popular for making clothes. We use many items made form nylon like socks, ropes, tents tooth brushes car seat belts sleeping bags, curtains etc. Nylon is also used for making parachutes and ropes for rock climbing

 

Question 13

Why polyester is quite suitable for making dress materials? Name any two types of polyester and their uses

Solution:
Fabric made from polyester does not get wrinkled easily. It remains crisp and is easy to wash. So it is quite suitable for making dress material. You must have seen people wearing nice polyester shirts and other dresses. Terylene is a type of popular polyester. It can be drawn into very fine fibres that can be woven like any other yarns

PET is a very familiar form of polyester. It is used for making bottles, utensils, films, wires and many other useful products. Look around and make a list of things made of polyester
 

Question 14

What is the chemical nature of polyester? What are polycot and polywool?


Solution:
Polyester (poly + ester) is actually made up of the repeating units of a chemical called an ester. Esters are the chemicals which give fruits their smell. Fabrics are sold by names like polycot, polywool, terry cot etc. as the name suggests, these are made by mixing two types of fibres, polycot is a mixture of polyester and cotton. Polywool is a mixture of polyester and wool.

 

Question 15

By which material artificial wool is formed. Why artificial wool has become more popular than natural wool?

Solution:
Artificial wool is prepared from another type of synthetic fibre called acrylic. The wool obtained from natural sources is quite expensive whereas materials made from acrylic are relatively cheap. They are available in a variety of colours. Synthetic fibres are more durable and affordable which makes them more popular than natural fibres.

 

Question 16

Why is it advised not to wear synthetic clothes while working in a laboratory or working with fire in the kitchen?

Solution:
The synthetic fibres melt on heating. This is actually a disadvantage with synthetic fibres. If 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.

 

Question 17

Write some characteristics of synthetic fibres which make them popular dress materials

Solution:
Synthetic fibres possess unique characteristics which make them popular dress materials. They dry up soon, are durable less expensive, readily available and easy to maintain.

 

Question 18

What is thermoplastic and thermosetting plastic?

Solution:
Some plastics can bend easily while some break when forced to bend. When we add hot water to a plastic bottle, it gets deformed. Such plastic which gets deformed easily on heating and can be bent is known as thermoplastic.


On the other hand, there are some plastics which when moulded , cannot be softened by heating. These are called thermosetting plastics

 

Question 19

Write some uses of bakelite

Solution:
Bakelite is a poor conductor of electricity. It is also heat resistant and used for making electrical switches, handles of various utensils. Etc

 

Question 20

Write some properties and uses of melamine

Solution:
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.

 

Question 21

Write some properties of plastic which make them as materials of choice

Solution:
Some characteristic properties of plastic are

i. plastic is non reactive and non corrosive

ii. plastic is light strong and durable

iii. plastics are poor conductors of heat and electricity
 

Question 22

Write short notes on the following

 

a. plastic and health care industry b. plastic cookware c. Teflon d. fire proof plastic


Solution:
a. Plastic and health care industry: plastic find extensive use in the health care industry. Some examples of their use in health care are the packaging of tablets, threads used for stitching wounds, syringes, doctors, gloves a number of medical instruments

b. Plastic cookware: plastic cookware is used microwave ovens for cooking food. The heating process is different in microwave ovens. Heat cooks the food but does not affect the plastic vessel

c. Teflon: Teflon is non-stick plastic used as non-stick coating in cookwares. Because of its toughness it is also used as tape for sealing purpose

d. Fire proof plastics: Although synthetic fibre catches fire easily, it is interesting to know that the fire proof material is made from synthetic plastics.
 

Question 23

What are biodegradable and non-biodegradable materials?

Solution:
A material which gets decomposed through natural processes ,such as action by bacteria, is called biodegradable. A material which is not easily decomposed by natural processes is termed as non-biodegradable.

 

Question 24

Whether following materials are biodegradable or non-biodegradable:

i. peels of vegetable and fruit peels, leftover foodstuff etc

ii. paper

iii. cotton cloth

iv. woolen items

v. wood

vi. tin, aluminium and other metal cans

vii. plastic bags


Solution:
i. biodegradable

ii. biodegradable

iii. biodegradable

iv. biodegradable

v. biodegradable

vi. non- biodegradable

vii. non – biodegradable
 

Question 25

What are the 4 ways to overcome the problem of waste accumulation?

 

Solution:
reduce their use , reuse, recycle, and recover




Test Your Skills Now!
Take a Quiz now
Reviewer Name