EASY
Diploma
IMPORTANT
Earn 100

Compare the positional and directional order in a crystalline solid, a nematic phase liquid crystal, and a pure liquid. Show your answer by stating yes or no in a copy of table 1.

  Crystalline Solid Nematic phase liquid crystal Pure liquid
Positional order      
Directional order      

 

Important Questions on Materials

EASY
Diploma
IMPORTANT
Outline any two principles of a liquidcrystal display device.
EASY
Diploma
IMPORTANT
Many of the compounds produced by cracking are used in the manufacture of addition polymers. State the essential structural feature of these compounds and explain its importance.
EASY
Diploma
IMPORTANT
The polymers often have other substances added to modify their properties. One group of additives are plasticizers. State how plasticizers modify the physical properties of polyvinyl chloride and explain at the molecular level how this is achieved.
EASY
Diploma
IMPORTANT
During the formation of poly(styrene), a volatile hydrocarbon such as pentane is often added. Describe how this affects the properties of the polymer and give one use for this product.
EASY
Diploma
IMPORTANT
The manufacture of low density poly(ethene) is carried out at very high pressures and at a temperature of about 500 K. A catalyst (either an organic peroxide or a trace of oxygen) is added to the ethene. Explain how the catalyst reacts and write equations to show the mechanism of the polymerization.
EASY
Diploma
IMPORTANT
How will the human immune system cope with particles on the nanoscale?
EASY
Diploma
IMPORTANT
How can the world control nano-weapons, which are easier and cheaper to build and less detectable than conventional weapons?
EASY
Diploma
IMPORTANT
How should decisions regarding funding be made, and by whom?