Synthetic fibres and plastics Worksheet-4

Synthetic fibres and plastics Worksheet-4

 

  1. We should not wear synthetic clothes in summer, why?

 

  1. Give some uses of PET.

 

  1. Why is melamine used for making kitchenware?

 

  1. Why are plastics preferred for storing pickles?

 

  1. Handles of frying pans are made of plastic. Why?

 

  1. Differentiate between biodegradable and non-biodegradable materials.

 

  1. Should the handle and bristles of a tooth brush be made of the same material? Explain your answer.

 

  1. Why is rayon also known as artificial silk? Give its two uses.

 

  1. Give three advantages of polythene over natural materials.

 

  1. Give one use each of bakelite, nylon and acrylic.

 

Answer:

  1. Most of the fabrics made from synthetic fibres absorb very little moisture. They become sticky when the body sweats, which makes them uncomfortable to wear in hot weather.

 

  1. Polyethylene terephthalate is used for making

(1) Plastic bottles for soft drinks.

(2) Containers for food and other edible liquid material.

(3) Used in solar cells.

 

  1. Melamine is hard durable and versatile. It resists heat better than other plastics hence it is used for making kitchen ware.

 

  1. Plastics do not react with contents of the pickles and also does not get corroded hence plastics are used for storing pickles.

 

  1. Plastics are bad conductors of heat so handles of frying pans are made up o plastics.

 

  1. The substances that can be degraded or decomposed by microorganisms (i.e. by natural processes) are called biodegradable substances. For example: Kitchen food scraps, paper, egg shells, human and animal waste, cardboard boxes, these substances decompose into soil.

The substances that are not affected by microorganisms or which never decompose are called non biodegradable substances. For example: Metal cans, Plastic bottles, Toxic chemicals.

 

  1. The handle and bristles of toothbrush are made up of different material. The handle is made up of plastic and bristles of nylon. Bristles are soft at the same time cannot be broken hence they provide efficient cleaning of teeth.

 

  1. Ryon is shiny and lustrous and resembles silk in appearance.

It is a regenerated synthetic fibre. It is produced from Cellulose which is a naturally occurring fibre.

Hence Ryon is called artificial silk.

 

  1. (1) Polyethene films are one of the most lightweight and durable packaging materials.

(2) Polyethene bags use less energy and resources to create than paper or cloth.

(3) Clear polyethene allows viewing the contents.

(4) Plastic packaging also reduces food spoilage.

 

  1. Uses of Nylon:

Nylon is the strongest material because of this reason it is extensively used in making parachutes and ropes for rock climbing.

It is also used for packing food stuffs. Sausages and meat are packed in sheaths made up of nylon.

Uses of Bakelite:

It is used for making electrical switches, handles of various utensils, etc.

Uses of Acrylic:

It is used for making sweaters, socks, shawls, carpets and blankets.