Tag: garbage in, garbage out

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Questions Related to garbage in, garbage out

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.

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

Which of the following are not thermosetting polymers ?

  1. Bakelite

  2. polystyrene

  3. PVC

  4. Melmac
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

Thermosetting polymers have different properties to thermosoftening polymers. Once moulded, they do not soften when heated and they cannot be reshaped. Vulcanised rubber is a thermoset used to make tyres. Its polymer chains are joined together by cross-links, so they cannot slide past each other easily.


Examples are given below:
  • Polyester fibreglass systems: sheet molding compounds and bulk molding compounds
  • Polyurithane insulating foams, mattresses, coatings, adhesives, car parts, print rollers, shoe soles, flooring, synthetic fibers, etc. Polyurethane polymers are formed by combining two bi- or higher functional monomers/oligomers.
  • Vulcanized rubber
  • Bakelite, a phenol formaldehyde resin used in electrical insulators and plasticware
  • Duroplast, light but strong material, similar to bakelite used for making car parts


Polyvinyl chloride(PVC) and polystyrene are thermoplastic polymer.
Hence, options B and C are correct.

Multiple choice chemistry synthetic fibres and plastics environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

State whether true or false :

Plastics are insoluble in water.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 Plastics are high molecular weight (macromolecular or polymeric) organic substances that are synthesized from low molecular weight compounds. 


The organic monomers are hydrophobic in nature due to the presence of hydrocarbons and thus makes plastics water insoluble.


Example: polyethene- a polymer of ethylene.

Therefore, option A is correct.

Multiple choice chemistry synthetic fibres and plastics environmental impact: plastics plastic plastic plastic waste garbage in, garbage out
Statement: Teflon doesn't stick to the materials and can be easily used in non-sticky pans and other cookware.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Teflon is a synthetic polymer of polytetrafluoroethylene that can be used to cover the surface of a certain object and imparts nonstick properties to it.  


Teflon is used for non-stick material because :


1. It is highly inert, i.e. doesn’t react with other substances easily.

2. It has a high melting point and shows exceptional electrical properties, which makes it an excellent choice to be used for the wiring of computer and aerospace applications.

3. Non-stick quality, which is why it’s used in numerous frying pans, pots, and other culinary tools.

Hence, the given statement is $\text{true}$.

Multiple choice chemistry synthetic fibres and plastics environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Statement: Plastics which get deformed easily on heating and can be bent easily are known as thermoplastics.


State whether the given statement is true or false.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plastics are categorized into thermosoftening/thermoplastic and thermosetting/thermoset plastics.


In thermosoftening/thermoplastic, the forces between the polymer chains are weak, so they can easily be remoulded into new shapes. 

This makes it possible to recycle this type of plastic. whereas in thermosetting plastics there are strong covalent bonds forming cross-links between the polymer chains, making these plastics hard and rigid. Once set into its original shape, a thermosetting plastic can't be softened and remoulded. 

The strong bonds between polymers also mean that thermosetting plastics are much more heat resistant than thermosoftening ones.

Hence, the given statement is $\text{true}$

Multiple choice chemistry synthetic fibres and plastics environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Plastics are capable of molding and casting into various shapes and size plastic.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plastics are categorized into thermosoftening and thermosetting plastics.
In thermosoftening plastics, the forces between the polymer chains are weak, so they can easily be remoulded into new shapes. This makes it possible to recycle this type of plastic. whereas in thermosetting plastics there are strong covalent bonds forming cross-links between the polymer chains, making these plastics hard and rigid. Once set into its original shape, a thermosetting plastic can't be softened and remoulded. The strong bonds between polymers also mean that thermosetting plastics are much more heat resistant than thermosoftening ones.
Example: Melamine is an example of a thermosetting plastic and polythene is a thermosoftening plastic.
Option A is correct

Multiple choice chemistry synthetic fibres and plastics environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

State whether true or false :

Bakelite is the first synthetic thermosetting plastics.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bakelite is prepared in laboratories by controlling the pressure and temperature applied to phenol and formaldehyde. 


Baekeland produced a hard moldable material which he named "Bakelite". 

It was the first synthetic thermosetting plastic ever produced.

Therefore, option A is correct