CBSE Class 8 Science Synthetic Fibers And Plant Worksheet

CBSE Class 8 Science Worksheet - Synthetic Fibers And Plant. Revision worksheets, Sample papers, Question banks and easy to learn study notes for all classes and subjects based on CBSE and CCE guidelines. Students and parents can download free a collection of all study material issued by various best schools in India. The study material has been carefully compiled by the best teachers in India. The students should practice the questions database to get better marks in examination. Please refer to other links for free download of high quality study material. Based on CBSE and CCE guidelines. Based on the same pattern as released by CBSE every year. Study material for final/ term/ SA1/ SA2 Examinations conducted by various schools affiliated to Central Board of Secondary Education (CBSE) in India and abroad. CBSE Study material has been compiled to help students preparation which will helps the students to concentrate more in areas which carry more marks.

A. Multiple choice questions:

Question. Which of the following fibres gives wool-like feeling?
(a) nylon
(b) acrylic
(c) terylene
(d)rayon
Answer. b- acrylic

Question. Which of the following is not a thermoplastic?
(a) polythene
(b) melamine
(c) polyester
(d) PVC
Answer. b-melamine

Question. Which of the following is used for making water pipes?
(a) melamine
(b) polythene
(c) PVC
(d) Bakelite
Answer. c-PVC

Question. Terylene mixed with cotton from_____________.
(a) terrycot
(b) terrywool
(c) terrysilk
(d) polyester
Answer. a-terrycot

B. FILL IN THE BLANKS-
1.Synthetic fibres absorb very little water. This property is called ______.
2. Thermosetting plastic does not become _______ on heating.
3. Plastic wastes dumped in water cause _______
4. _______ is a common plastic known for its lightness and rigidity.
Answer.
1. Drip dry              2. Soft
3. Water pollution   4. Thermocol

C. VERY SHORT ANSWER QUESTION-

Question. Name the smallest unit of nylon.
Answer. The smallest unit of nylon is amide.

Question. Give any two examples of thermoplastics.
Answer. The two examples of thermoplastics are-
1. PVC 2. Polythene

Question. Give two examples to show that plastics are non-reactive in nature.
Answer. (a.) Plastics are non-reactive with water. That is why plastic containers such as bottles and buckets are used to store water.
(b.)Plastics are non reactive so pickles are stored in them.

Question. Which fibre is also called artificial silk?
Answer. Rayon is also called artificial silk.

Question. Name the monomer of polyester.
Answer. The monomer of polyester is ester.

Question. Give two examples of plastics.
Answer. The two examples of plastics are-
(a) Bakelite (b) Polythene

D. SHORT ANSWER QUESTIONS-

Question. What are human-made or synthetic fibres?
Answer. Fibres obtained through different chemical processes in the industries are called human-made or synthetic fibres. Rayon, nylon and terylene are some human-made or synthetic fibres.

Question. What is a polymer?
Answer. A polymer is a very large unit formed by the combination of a large number of smaller molecules (called monomers) joined end to end by chemical bonds.

Question. Why is nylon used for making bristles of toothbrushes?
Answer. Due to its high tensile strength, nylon is used for making bristles of toothbrushes.

Question. What is 5-R principal?
Answer. In order to save environment from harmful effects of plastic, we should use 5R principal-reduce, reuse, recycle, recover and refuse.
(a) Reduce- It means that we should use less like save water by repairing leaky taps.
(b) Reuse- It means to use an item again after it has been used.
(c) Recycle-This means we should collect items like plastic ,paper, and glass use materials to make new products, instead of using new plastic.
(d) Recover- It means converting waste into resources .
(e) Refuse- We can refuse to use products which are harmful to the environment.

Question. (a). What are plastics?
Answer. Plastics are polymers made up of a very large number of small units joined end to end to form long chains.

(b). Give any two uses of plastics.
Answer. 1. Plastics are used to store various kinds of food material and many chemicals.
2 Plastics are used to make buckets, tubs, and most of our household articles.

Question. Give the difference between thermosetting plastics and thermoplastics.
Answer.
THERMOPLASTIC                                                                   THERMOSETTING PLASTICS
Plastics that easily get deformed                                            Plastics that once moulded into a shape do not
on heating and can be bent easily                                          become soft on heating and cannot be moulded again.
They are less tough as compared to thermosetting plastics.     They are more tough and rigid.
They are less resistance to high temperatures.                       They are resistance to high temperature.
They can be recycled.                                                           They cannot be recycled.
Examples- PVC, Polyesters                                                    Examples- Bakelite, Formica

Question. (a) Why is polyester used for making water hoses for firefighting operations?
Answer. Polyester is strong and resistant to chemicals and abrasion that’s why it is used for making water hoses for firefighting operations.

(b) Why are saucerpan handles, electric plugs and switches made of thermosetting plastics?
Answer. Thermosetting plastics are bad conductor of electricity i.e. they donot allow electricity to pass through them so they are used to make saucerpan handles, elecrtric plugs and switches.

E. LONG ANSWER QUESTIONS-

Question. Give any five environmental hazards caused due to plastics.
Answer. Five environmental hazards caused due to plastics are-
1. Plastics are not at all ecofriendly. Some plastics can be recycled but recycled plastics are inferior in quality.
2. Plastics burn slowly and release toxic fumes.
3. Plastics are nonbiodegradable and keep accumulating in landfills.
4. Plastics and polythene bags choke the drains and create a lot of drainage problems. This also leads to eutrophication causing harm to aquatic life.
5. Inferior quality plastics prove to be hazardous if used in food packing or eatables.

Question. What are the advantages of synthetic fibres? Explain.
Answer. The advantage of synthetic fibres are-
(a) Synthetic fibres can be produced on a large scale and, hence, they cost less.
(b) These fibres are strong, durable and shiny.
(c) These fibres require less care and do not need frequent ironing as they are wrinkle free.
(d) The manufacture of fully synthetics fibres is helping in the conservation of forest.

Question. Write any five eco-friendly habits.
Answer. Five eco-friendly habits are-
1. Limit the use of plastics.
2. Use paper or cloth bags instead of polythene.
3. Do not throw plastics or polythene into water bodies.
4. Do not burn plastics.
5. Avoid wearing synthetic clothes in kitchen.

Question. Give reasons for the following-

1. Cooking pans have plastics handles.
Answer. Cooking pans have plastics handles because they do not conduct heat and are good insulators of heat.

2 Burning of plastics causes air pollution.
Answer. Plastics do not get completely burnt and produce toxic gases and smoke that causes air pollution.

3 Electric wires have a plastics covering.
Answer. The electric wires are covered with plastics as they are insulators or bad conductor of electricity. They are used for the safety as they prevent electric shock.

4 Plastics are strong and durable.
Answer. Plastics are strong and durable as they can be moulded into different shapes and sizes.

More Question

Fill up the blanks :

1. Fibres we get from plant and animals are called ______________.
2. Artificial fibres are commonly called _________________.
3. The simple molecule of molecule in a polymer is called _____________.
4. The polymer of natural fibre cotton is called ______________.
5. The material which can easily be molded is called ________________.
6. The process by which artificial fibres are made from simple fibre is called _______________.
7. The raw material used for the production of rayon is ______________.
8. ________________ is made by the polymerisatin of amide molecules.
9. Terylene is obtained by the polymerising the molecule of ___________ and _________________.
10. Acrylic fibre is obtained by the polymerisation of molecules of _________________.
11. Koroseal is the trade name of ________________.
12. PVC stands for ________________.
13. PET stands for __________________.
14. _________________ prepared by the polymerization of vinyl chloride molecules.
15. Two examples of thermoplastic.

Please refer to attached file for CBSE Class 8 Science Worksheet - Synthetic Fibers And Plant