NCERT Class VIII Science Solution: Chapter 3-Synthetics Fibres and Plastics Part 4

Download PDF of This Page (Size: 169K)

Question 22:

Fill in the blanks.

  1. A polymer is a chain of many small units joined together which are called ______.

  2. The synthetic fibres are also known as ______ fibres.

  3. The first fully synthetic fibre was ______.

  4. A fibre similar to wool is ______.

  5. A plastic used for making crockery is ______.

Answer:

  1. A polymer is a chain of many small units joined together which are called monomers.

  2. The synthetic fibres are also known as man-made fibres.

  3. The first fully synthetic fibre was nylon.

  4. A fibre similar to wool is acrylic.

  5. A plastic used for making crockery is melamine.

Question 23:

Match items in List A with the items of list B.

Match Items in List a with the Items of List B.(Q)
Match items in List A with the items of list B.(Q)

List A

List B

Nylon

Non-stick coating

PET

Electric switches

Rayon

Parachutes

Thermosetting plastics

Polyester

Teflon

Artificial silk

Answer:

Match Items in List a with the Items of List B.(A)
Match items in List A with the items of list B.(A)

List A

List B

Nylon

iii Parachutes

PET

iv Polyester

Rayon

v Artificial silk

Thermosetting plastics

ii Electric switches

Teflon

i Non-stick coating

Question 24:

Unscramble the jumbled words given below, related to synthetic materials.

  1. anory

  2. lopmery

  3. relyteen

  4. laspict

  5. yespolter

  6. felton

Answer:

  1. Rayon

  2. Polymer

  3. Terylene

  4. Plastic

  5. Polyester

  6. Teflon

Image of natural and synthetic materials

Natural and Synthetic Materials

Image of natural and synthetic materials

LONG ANSWER QUESTIONS

Question 25:

Indicate whether the following statements are true or false. Also write the false statements in their correct form.

  1. The fabric terywool is obtained by mixing Terylene and wool.

  2. Synthetic fibres do not melt on heating.

  3. It is risky to wear synthetic clothes while working in the kitchen.

  4. Most of the plastics are biodegradable.

Answer:

  1. The fabric terywool is obtained by mixing Terylene and wool. (True)

  2. Synthetic fibres do not melt on heating. (False)

    Hint: Synthetic fibres melt on heating.

  3. It is risky to wear synthetic clothes while working in the kitchen. (True)

  4. Most of the plastics are biodegradable. (False)

    Hint: Most of the plastics are non-biodegradable.