Pick the synthetic fibre out of the following?
Which of the following is a source of rayon?
(c) Wood pulp
Polycot is obtained by mixing:
(a) Nylon and wool
(b) Polyester and wool
(c) Nylon and cotton
(d) Polyester and cotton
Which is a thermosetting plastic?
The material similar to silk in appearance is:
The most suitable material for the preparation of handles of cooking utensils is:
Which of the following is not a common property of plastics?
(b) Light in weight
(d) Good conductor of electricity
Which of the following represents the correct match for items in Column A with those in Column B?
Column A Column B
I. Nylon (i) Thermoplastic
II. PVC (ii) Thermosetting plastic
III. Bakelite (iii) Fibre
(a) I-(ii), II-(iii), III-(i)
(b) I-(iii), II-(i), III-(ii)
(c) I-(ii), II-(i), III-(iii)
(d) I-(iii), II-(ii), III-(i)
Which of the following groups contain all synthetic substances?
(a) Nylon, Terylene, Wool
(b) Cotton, Polycot, Rayon
(c) PVC, Polythene, Bakelite
(d) Acrylic, Silk, Wool
The material which is commonly used for making kitchen containers is:
VERY SHORT ANSWER QUESTIONS (8)
Cotton is a natural polymer. What is its chemical name?
A synthetic fibre which looks like silk is obtained by chemical treatment of wood pulp. It is, therefore, known as artificial silk. What is its common name?
Terrycot is made by mixing two types of fibres. Write the names of the fibres.
Terylene and cotton
Plastic articles are available in all possible shapes and sizes. Can you tell why?
Plastic is easily mouldable, therefore the plastic articles can be made in any shape and size.
Plastic is used for making a large variety of articles of daily use and these articles are very attractive. But it is advised to avoid the use of plastic as far as possible. Why?
Plastics are non-biodegradable, hence not environment friendly, thereby causes environmental pollution.
Why is it not advisable to burn plastic and synthetic fabrics?
When plastic and synthetic fabrics are burnt, they release poisonous gases, causing air pollution.
Select the articles from the following list which are biodegradable.
(b) Woollen clothes
(d) Aluminium can
(e) Plastic bag
(f) Peels of vegetables
Paper, woollen clothes, wood and peels of vegetables are biodegradable.
A bucket made of plastic does not rust like a bucket made of iron. Why?
Since plastic is a non-reactive material, it does not react with air and water, and hence there is no rusting of plastic.
SHORT ANSWER QUESTIONS (11)
Rohit took with him some nylon ropes, when he was going for rock climbing. Can you tell why he selected nylon ropes instead of ropes made of cotton or jute?
Compared to cotton and jute ropes, nylon ropes are much stronger, more elastic and lighter.
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?
Acrylic blankets are:
· Easily washable
· Dry easily
· Light in weight
· Available in a variety of colours and designs
These are the reasons why people may prefer acrylic blanket over woollen blanket.
PVC (polyvinyl chloride) is a thermoplastic, which is used for making toys, footwear, etc. Bakelite is a thermosetting plastic, and is used for making electrical switches, handles of various utensils, etc. Can you write the major difference between these two types of plastics?
Thermoplastics, at high temperatures become deformed and bend easily, and are therefore used for making toys. On the contrary, thermosetting plastics, once moulded cannot be softened, even on heating. This property makes them suitable for making electrical switches, handles of various utensils, etc.
Fill in the blanks:
(i) A polymer is a chain of many small units joined together which are called
(ii) The synthetic fibres are also known as ______ fibres.
(iii) The first fully synthetic fibre was ______.
(iv) A fibre similar to wool is ______.
(v) A plastic used for making crockery is ______.
Match items in List A with the items of list B.
List A List B
(a) Nylon (i) Non-stick coating
(b) PET (ii) Electric switches
(c) Rayon (iii) Parachutes
(d) Thermosetting plastics (iv) Polyester
(e) Teflon (v) Artificial silk
Unscramble the jumbled words given below, related to synthetic materials.
State whether the following statements are True or False. Also write the false statements in their correct form.
(i) The fabric terywool is obtained by mixing terylene and wool.
(ii) Synthetic fibres do not melt on heating.
(iii) It is risky to wear synthetic clothes while working in the kitchen.
(iv) Most of the plastics are biodegradable.
(ii) False, synthetic fibres melt on heating
(iv) False, most of the plastics are non-biodegradable.
Write the importance of synthetic polymers in our life.
Synthetic polymers like nylon are strong and are therefore used in making ropes, seatbelts and tyre cords. Nylon is also used for making things required for our daily use, such as, umbrella, coat, kite, carpet and elastic hosieries. Acrylic fibre is used for making sweaters, jerseys and blankets, as it is a warm fibre. Terylene is another strong fibre, which is elastic in nature. It absorbs very little water and is therefore used for making nets, hoses, ropes, medical textiles, etc. PET is used for making bottles and containers for storing liquid and food items.
Despite being very useful it is advised to restrict the use of plastic. Why is it so? Can you suggest some methods to limit its consumption?
Plastic is a non-biodegradable material and causes environmental pollution.
Burning of plastic in the form of garbage causes serious air pollution. We should therefore reduce its use, reuse it for other purposes and recycle it.
Some of the methods to limit its consumption are:
· Using paper bags where ever possible
· Choosing ceramic ware, boxes or cardboard packing, instead of buying plastic bottles
· Using reusable bags in grocery stores
· Encouraging self and others buying products wrapped in biodegradable materials
Write an activity to show that synthetic fibres are stronger than the cotton fibres.
We can hang different weights from the threads of same thickness of any synthetic fibre and cotton separately. We will keep on increasing the weights till the threads break.
We will find that more weight is required to break a synthetic thread than a cotton thread.
Complete the crossword given below with the help of clues.
1. Substance used as synthetic wool (7)
2. A plastic used for making containers and carry bags (9)
3. Substance made up of large number of smaller molecules (7)
4. Another name for this compound is artificial silk (5)
5. A type of fibre obtained naturally from cocoon (4)
6. A synthetic fibre classified as polyester (8)
7. A polymer used for making rope (5)