Tag: man made materials

Quizzes (8) Questions (131)

Questions Related to man made materials

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

We come to a conclusion, that plastics are bad conductors of electricity from the following.

  1. Refrigerators and freezers have a plastic foam core

  2. Electrical wires have a plastic covering

  3. Cooking pans have plastic handles

  4. We use to prepare parachutes
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

Most of the commonly used household electronics like freezers, washing machine, etc are made of plastic since it is the bad conductor of electricity.

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Which of the following is/are reasons of using plastics?
1.They are transparent.
2. They are cheap.
3. They can be moulded into diffrent shapes.

  1. (1) only

  2. (2) only

  3. (1) and (3) only

  4. (2) and (3) only
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
All three are correct. But the reason for their vast use is the less expenditure and re-usability. 
With the increased knowledge of plastics and the improved capabilities of machining equipment, the industry is now capable of producing plastic components to the same exacting standards as metallic components.
Plastics are cheaper than metals.  They are transparent and elastic material that could be molded when heated. Plastics are easy to reuse as they can be molded into different shapes can be designed for resist impact and dents, making it durable, strong, and stable.


Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Fibre obtained by chemical treatment of wood pulp is called:

  1. natural Silk

  2. rayon

  3. nylon

  4. polyster
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Natural Silk: The protein fibre of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons.
Rayon: Rayon is a manufactured regenerated cellulose fibre. It is made from purified cellulose, primarily from wood pulp, which is chemically converted into a soluble compound.
Nylon: Nylon is a strong, light synthetic fibre. Nylon thread is made from the polymerization of an amine and an acid chloride. 
Polyester: Polyester is a synthetic polymer made of purified terephthalic acid or its dimethyl ester dimethyl terephthalate and mono ethylene glycol. 

Hence, the correct option is $B$
Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Which is NOT the general characteristics of plastics?

  1. Good electrical insulators

  2. Acceptable acoustic insulation

  3. Resistant to corrosion and many chemical factors

  4. Have a high production cost
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The properties and characteristics of most plastics (though not always fulfilled in certain special plastics) are these:
Easy to work and shape,
Have a low production cost,
Possess low density,
Tend to be waterproof,
Good electrical insulators,
Acceptable acoustic insulation,
Good thermal insulation, but most can not withstand very high temperatures,
Resistant to corrosion and many chemical factors;

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Teflon constitutes:

  1. carbon,flourine & hydrogen

  2. carbon,chlorine & hydrogen

  3. carbon & flourine

  4. carbon & chlorine
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Teflon is the brand name of Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene. The constituents of tetrafluoroethylene are carbon and fluorine formula is $ (C _2F _4) _n$. 

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Which of the following is thermosetting polymer?

  1. Nylon

  2. Sealing wax

  3. Polysiloxanes

  4. Both B and C
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Thermosetting polymers: These polymers are cross linked or heavily branched molecules, which on heating undergo extensive cross linking in moulds and again become infusible. These cannot be reused. Some common examples are polysiloxanes, bakelite, urea- formaldehyde resins, etc.

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Three-dimensional molecules with cross-links are formed in the case of a:

  1. thermosetting plastic

  2. thermoplastic

  3. both (a) and (b)

  4. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Thermosetting plastic consists of chain of the  molecules which are cross-linked, with each other when heated. When thermosetting plastics cross-link, the molecules create a permanant, network  which is a $3-D$ structure and can be considered one giant molecule. Once cured, thermosetting plastic cn not be remelted, in the same way that cured concrete cannot be reset. 

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Garden chairs made of plastic strips and plastic articles get faded, worn out and cracked in sunlight, mainly because of:

  1. Low melting point of plastic

  2. Ultraviolet rays

  3. Heat

  4. The red colour
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Garden chairs made of plastic strips and plastic articles get faded, worn out and cracked in sunlight, mainly because of UV rays. All types of UV can cause a photochemical effect within the polymer which can lead to degradation of some sort to the materials. Absorbed UV energy can exits the photon in a plastic, exciting the photons can create free radicals. Those free radicals can cause breaks in the polymer bonds.