Tag: chemistry

Natural polymers occur in nature and can be extracted. 

Llama and Alpaca species found in South America yield wool.

Acrylic fibers are synthetic fibers made from a polymer (polyacrylonitrile) with an average molecular weight of approx 100,000, about 1900 monomer units. 

There are two types of polymers: synthetic and natural. 

Polyisoprene is a natural polymer made of isoprene as the monomeric unit.

Acetate rayon is a organic polymer formed by acetylation of all remaining -OH's of linear cellulose chain. It is a synthetic filament, yarn, or fabric composed of a derivative of the acetic ester of cellulose.

Cellulose is not a synthetic polymer. It is a natural polymer.
It is a polysacchardie having molecular formula $(C _6H _{10}O _5) _n$. It has linear chain of $\beta(1\rightarrow 4)$ linked D-glucose units. There are several hundred to many thousands of such units in a chain.  Cellulose is an important structural component of  in the primary cell wall of green plants, many forms of algae and the oomycetes.

Ornaments and jewellry can't be made of 100 per cent pure gold or 24 Karat gold as it is very soft and delicate. Most of jewellry are made of 22 karat to 10 karat of gold.

Non-metals like phosphorous exist in various colors such as white, scarlet, yellow, red, violet, black. Similarly, sulfur is pale yellow, bromine is red-brown colored in liquid and vapor state.
Thus option $A$ is correct.

The melting point of an element is the temperature at which it converts from solid form to a liquid. In metals, there are two types of bonding that lead to higher melting points: covalent and metallic. Covalent bonds are when electron pairs are shared equally between atoms, and they pull atoms even closer together if multiple pairs of electrons are involved. Metallic bonds involve electrons that are delocalized: they float between many atoms, not just two, and positively charged nuclei are firmly bound to the surrounding "sea" of electrons. As strong bonds between atoms give elements higher melting points, it is also true that lower melting points are a result of weaker bonds or a lack of bonds between atoms. Therefore non-metals lack metallic bonding between atoms therefore have lower melting and boiling point than metals.
Also the closed and dense packing of metals in the lattice impart them high density and strength that lacks in non-metals.
Thus option A is true.