synthetic fibres and plastics class 8 extra questions, assertion reason type questions

SYNTHETIC FIBRES AND PLASTICS- IMPORTANT QUESTIONS

synthetic fibres and plastics class 8 extra questions, assertion reason type questions

FILL IN THE BLANKS:

1. Rayon is obtained by the chemical treatment of ---------

2. --------is the synthetic fibre used to make parachutes.

3. The synthetic fibre which resembles wool is -------

4. Polycot is a mixture of -------- and cotton.

5.The plastic which can be deformed easily on heating is known as ---------

6. ---------- is used to make handles of utensils.

7. A material which is not easily decomposed by natural processes are called --------

8. Plastics are ---------- of heat and electricity.

9. Uniforms of firemen have a coating of ---------- to make them flame resistant.

10. ----------- is used for non-stick coating on cookware.

ASSERTION-REASON QUESTIONS

Select the correct option for the following assertion-reason questions:

a. (A) is correct and (R) is the correct explanation of (A).

b. (A) is correct and (R) is not the correct explanation of (A).

c.(A) is correct and (R) is wrong.

d. (A) is wrong and (R) is correct.

1. Assertion(A): Bakelite is used for making electrical switches.

Reason(R): Bakelite is a poor conductor of electricity.

2. (A) Thermosetting plastics can not be remoulded.

(R) Thermosetting plastics can be softened on heating.

3. (A) Synthetic fibres are more popular than natural fibres.

(R) Synthetic fibres are more durable and less expensive.

4. (A) Nylon fibres can not be used for making ropes for climbers.

(R) Nylon fibres are very strong fibres.

5. (A) We should not use synthetic fabrics while working in the kitchen.

(R) Synthetic fabrics dry up quickly and are easy to wash.

SHORT ANSWER QUESTIONS:

1. Which fibre is called artificial silk? Why?

2. List five uses of nylon.

3. What are the uses of PET polymer?

4. What are the characteristics of synthetic fibres?

5. Differentiate thermoplastics and thermosetting plastics.

ANSWERS:

Fill in the blanks:

1. wood pulp

2. nylon

3.acrylic

4. polyester

5.thermoplastics

6. bakelite

7. non-biodegradable

8. poor conductors

9. melamine

10. teflon

Assertion-Reason type:

1. (a)

2. (c)

3. (a)

4. (d)

5. (b)