Tag: man made materials

Questions Related to man made materials

What characteristic property of plastic makes it useful in making containers for storing food items?

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  1. They do not react with food stored in them

  2. They are poor conductors of electricity

  3. They are light weight and strong

  4. They are non-degradable.

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Correct Option: A,C
Explanation:

Since plastics do not react with water and air, they are noncorrosive in nature and are thus used for storage.

An example of thermosetting plastic, which is also a poor conductor of electricity, is:

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  1. polythene

  2. bakelite

  3. polyester

  4. PVC

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Correct Option: B
Explanation:

Bakelite is an example of thermosetting plastic which is also a poor conductor of electricity. Due to its insulating character, it is used for switches and other electrical insulators.
Option B is correct.


State True or False.

Plastics are resistant to corrosion.

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  1. True

  2. False

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Correct Option: A
Explanation:

The given statement is true. Plastics are resistant to corrosion and chemicals.

Statement: The articles made of thermoplastics can be recycled whereas the articles made of thermosetting plastics cannot be recycled.


State whether the given statement is true or false.

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  1. True

  2. False

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Correct Option: A
Explanation:
The intermolecular forces in thermoplastics are weaker while the intermolecular forces in thermosetting plastics are stronger. The thermosetting plastics cannot be moulded on heating. Thus the articles made of thermoplastics can be recycled whereas the articles made of thermosetting plastics cannot be recycled.

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

A person has to make electric switches and plugs. Which material is recommended ?

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  1. Teflon

  2. Bakelite

  3. Rayon

  4. PVC

Show answer
Correct Option: B
Explanation:
Bakelite has high heat resistant property which makes it a poor conductor of heat and electricity.it is used for making electrical switches because it high heat resistance property protects us from electric shocks.
also it is used to make handles of cooking utensils because of this property it does not conduct heat and so the handles are prevented from becoming too hot and this makes it easy to handle the handles of cooking utensils.

Hence, the correct option is $\text{B}$

Match the column A and B

Column A Column B
(i) Thermoplastics (a) Handles of utensils, floor tiles
(ii) Thermosetting plastics (b) Melamine
(iii) Biodegradable (c) Teflon
(iv) Fire proof plastic (d) Wood
(v) Oil and water do not stick (e) Combs, containers
chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

  1. i-d, ii-e, iii-a, iv-b, v-c

  2. i-e, ii-a, iii-d, iv-b, v-c

  3. i-a, ii-d, iii-b, iv-c, v-e

  4. i-c, ii-b, iii-a, iv-e, v-d

Show answer
Correct Option: B
Explanation:
Thermoplastic materials are those materials that are made of polymers linked by intermolecular interactions or van der Waals forces, forming linear or branched structures.

Melamine is a versatile material. It resists fire and can tolerate heat better than other plastics. It is used for making fire-resistive uniforms, floor tiles, kitchenware and fabrics which resist fire. 

Thermosetting plastics are generally strong and resistant to heat, but they melt the first time they are heated to a high enough temperature and harden (set) permanently when cooled. They can never be melted or reshaped again. 

They are used in situations where resistance to heat is important, e.g. on kitchen work surfaces, good-quality plastic cups, saucepan handles and plug casings. Wood is biodegradable

Thermoplastics are:

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  1. linear polymers.

  2. soften or melt on heating

  3. molten polymer can be moulded in desired shape.

  4. All of these

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Correct Option: D
Explanation:

Thermoplastics are linear polymers. They are also known as thermosoftening plastics because they become malleable when heated. Although they are pliable above a certain heat threshold, they return to a solid once they have been sufficiently cooled. For this reason, thermoplastics are put to unique uses in a number of manufacturing and engineering industries.

Apart from their primary characteristics, thermoplastics vary slightly in usage and properties. For example, polystyrene is a hard, water-resistant thermoplastic, according to BBC. This makes it an excellent choice for creating toy models and for packaging that will not be exposed to extreme heat sources in transit. Polymethyl methacrylate is also a stiff thermoplastic, but it is also an electrical insulator and can be polished well, so it is often used in vehicle windows and light covers.

Which of the following is a thermosetting plastic?

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  1. PVC

  2. Polyethylene

  3. Bakelite

  4. Terylene

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Correct Option: C

Which of the following is used to make disposable cups?

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  1. Low density polyethylene

  2. Polypropylene

  3. Polystyrene

  4. PVC

Show answer
Correct Option: C
Explanation:

Disposable cups are made up of thermocol. It is a synthetic petroleum product which is made by restructuring of the chemical bonding of the polystyrene, to develop a stretch polystyrene. In this process, thermoplastic granules are expanded through the application of steam and air. The expanded granules become large and light in weight.

Thermosetting plastics can be remoulded on gentle heating.

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

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Thermosetting plastics: Which on heating becomes infusible these cannot be reused.Ex- Bakelite,urea formaldehyde resin.

Thermoplastic plastics: These become soft on heating and hard on cooling.
Ex.polythere,polystyrene.
Thermoplastic plastics can be remoulded.