Frequently Asked Questions
Explain why the following are made of thermosetting plastics
(a) Saucepan handles
(b) Electric plugs/switches/plug boards
Solution:
Explanation:
- The given substances, i.e. Saucepan handles and Electric plugs/switches/plug boards are made of thermosetting materials, as these are poor heat and electrical conductors.
- They also don't usually bend or deform.
- After heating and shaping pressure, thermosetting polymers harden permanently.
Final answer:
Hence, (a) Saucepan handles and (b) Electric plugs/switches/plug boards are made of thermosetting plastics because they have poor conduction of electricity and are durable.
Name two metals which are liquid at room temperature
Solution:
Explanation:
Metals:
- Metals have a shiny appearance and are said to be lustrous.
- Good conductors of heat and electricity.
- Malleable and ductile in nature.
- High melting and boiling points.
Final answer:
The metals which are liquid at room temperature are Mercury and Gallium.
Avoid plastics as far as possible Comment on this advice
Solution:
Explanation:
Plastic is described as a material that comprises an organic compound with a high molecular weight as an essential element and can also be known as long chain polymers.
Few characteristics of plastics can be mentioned as follows:
- Strong in nature
- Poor conductor of electricity
- Corrosion free
When plastic bags are burned, poisonous gases are generated, and when animals consume them, their respiratory systems are strangled, resulting in death.
Final Answer:
We should avoid using plastics as much as possible because they are non-biodegradable in nature. When they are discharged into the environment, they poison it.
Which of the following is a source of rayon
A: Wool
B: Wood pulp
C: PET
D: Silk
Solution:
Explanation:
Rayon is a synthetic fiber. It is obtained from a natural raw material named cellulose.
After chemical treatments, rayon is obtained.The cellulose is extracted from wood pulp.
Therefore, option B. is the correct answer.
Answer:
Hence the option B Wood pulp i.e is the correct answer.
Why is it said that air is a homogeneous mixture of various gases
Solution:
Explanation:
- Air is a homogeneous mixture of gases because it is mainly composed of nitrogen and oxygen.
- Its elements are not easily separated or distinguished from each other.
Final answer:
It is said that air is a homogeneous mixture of various gases because it is mainly composed of nitrogen and oxygen. Its elements are not easily separated or distinguished from each other.
