class-8 chapter - 3 subject- science

1. nidhi kaushik
class -8
chptr 3

2. Synthetic fibres are man-made fibres,
most of them are prepared from raw
material petroleum called
petrochemicals. All fabrics are obtained
from fibres, while fibres are obtained
from artificial or man-made sources.
THEY CONSIST OF A SMALL UNIT OR A
POLYMER WHICH IS MADE FROM MANY
REPEATING UNITS KNOWN AS MONOMERS.
THEY INCLUDE NYLON, ACRYLICS,
POLYURETHANE, AND POLYPROPYLENE.
MILLIONS OF TONS OF THESE FIBRES ARE
PRODUCED ALL OVER THE WORLD EACH

3. What is a synthetic fibre made up of?
A synthetic fibre, as well as plastic, is made up of a chain of small units
(called Monomers) which combine to form polymers.
Monomers: A monomer is a single molecule that can bond with other identical molecules
to form polymers through a process called Polymerization.
Polymers: Polymer is a Greek word in which 'poly' means 'many' and 'mer' means units.
Hence, polymers are large molecule made up of several molecules (or monomers) linked
together.

4. What are synthetic fibres
made up of?
All the synthetic fibres are
manufactured by
processing raw materials
of petroleum origin in a
number of ways. The raw
materials of petroleum
origin are called
Petrochemicals.

5. RAYON NYLON POLYESTER ACRYLIC

14. Why should we not wear synthetic clothes in the
kitchen?
Synthetic fibres melt on heating. If the clothes
catch fire, the fabric made up of synthetic fibres
will melt and stick to one's body. Hence, it is
recommended that one should not wear synthetic
clothes while working in the kitchen or laboratory.

16. TYPES
OF
PLAST
ICS

22. NCERT EXERCISE

23. NCERT EXERCISE
ARTIFICIAL OR
MANMADE FIBRES.
PETROCHEMICALS.
POLYMER.

24. NCERT EXERCISE

25. NCERT EXERCISE

26. NCERT EXERCISE

27. NCERT EXERCISE

28. NCERT EXERCISE

29. NCERT EXERCISE