Q 1 – Fill in the blanks:
- A ________ is large molecule made up of repeating units of small molecules.
- Fabrics made of _______ fibres are more comfortable than synthetic fibres as they allow more air circulation and absorption of sweat.
- An example of synthetic fibre which resembles wool is _______.
- A synthetic fibre which has the strength of a steel wire and is used for making ropes is
- __________ is a versatile polymer used to make floor tiles, kitchenware and fabrics which resist fire.
- All synthetic fibers are prepared by a number of processes using raw materials of petroleum and natural gas origin, called ____________.
1. A polymer
2. natural
3. Acrylic
4. nylon wire
5. Melamine
6. petrochemicals
Q 2 – Which of the following is obtained from a natural polymer?
(a) Rayon
(b) Nylon
(c) Polyester
(d) Acrylic
(a) Rayon
Q 3 – Terycot is a blended fiber made up of
(a) Cotton and rayon
(b) Polyester and wool
(c) Polyester and cotton
(d)Terylene and cotton
(d)Terylene and cotton
Q 4 – Which of the following correctly represents the chemical formula of the monomer of polythene?
(a) CH2= CHCl
(b) CF2=CF2
(c) CH2=CH2
(d) CH=CH3
(c) CH2=CH2
Q 5 – Thermacol is made from the synthetic polymer called
(a) Perspex
(b) Polythene
(c) Polystyrene
(d) Polyester
(c) Polystyrene
Q 6 – Write the full form of PET and its two uses.
PET, which stands for polyethylene terephthalate, is a clear, strong and lightweight plastic belonging to the polyester family. It is typically called “polyester” when used for fibers or fabrics, and “PET” or “PET Resin” when used for bottles, jars, containers and packaging applications.
Q 7 – Explain how throwing food waste in polythene bags can be hazardous for stray animals?
Because the stray animals can eat the plastic which is present in polythene bags. When they eat it they can get sick and even die because of us being so careless.
Q 8 – What do you understand by the term ‘Polymer’?
A chemical compound or mixture of compounds formed by polymerization and consisting essentially of repeating structural units
Q 9 – State two disadvantages of synthetic fibres.
Disadvantages…
- Synthetic fibres do not absorb water or sweat.
- Synthetic fibres on catching fire shrink forming beads which stick to the skin. Therefore it is not advisable to use clothes made from synthetic fibres while working near flam/fire, such as in kitchen
Q 10 – Explain why Rayon is called regenerated fibre.
Rayon is described as a regenerated fibre because the cellulose, obtained from soft woods or from the short fibres (linters) that adhere to cottonseeds, is converted to a liquid compound, squeezed through tiny holes in a device called a spinnerette, and then converted back to cellulose in the form of fibre.
Q 11 – Explain the following statements:
a) It is dangerous to wear synthetic clothes while working in a laboratory or kitchen.
b) Electrical switches are made of thermosetting plastics and not thermoplastics
Q 12 – Write two differences between thermoplastics and thermosetting plastics in tabular form.
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THERMOPLASTICS |
THERMOSETTING PLASTICS |
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1. PLASTICS WHICH CAN BE MOULDED REPEATEDLY BY HEATING AND COOLING ARE CALLED THERMOPLASTICS. 2. THE MONOMERS ARE ARRANGED IN A STRAIGHT CHAIN . |
1. PLASTICS WHICH CANNOT BE REMOULDED ONCE FORMED AE CALLED THHERMOSETTING PLASTICS. 2.THE MONOMERS ARE CROSS LINKED WITH EACH OTHER. |