Chemistry 1 Marks Question

Functionality means the number of binding sites in a molecule. For example, the functionality of ethene, propene, styrene, acrylonitrile is one while that of 1, 3-butadiene, adipic acid, terephthaliC' acid, hexa methylenediamine is two.

Buna-N is a copolymer of 1, 3-butadiene and acrylonitrile and Buna-S is a copolymer of 1, 3-butadiene and styrene.

Dacron is prepared by the condensation of terephthalic acid ethylene glycol in the presence of catalyst zinc acetate and antimony trioxide.

The names and structures of monomers are:
Buna-N is known as nitrile rubber.

The names and structures of monomers are:
Dacron is known as Polyethylene terephthalate.

Natural rubber becomes soft at high temperature (> 335K) and brittle at low temperatures (<283K). To improve physical properties of rubber, vulcanisation is carried out. This process consists of heating a mixture of raw rubber with sulphur and an appropriate additive at a temperature range between 373K to 415K. On vuclcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened.

It is a process of formation of a high molecular Sol. mass polymer from one or more monomers by linking together a large number of repeating structural units through covalent bonds.

The polymers which decompose on their own by bacterial action are called biodegradable polymers. Example of a biodegradable aliphatic polyester are Poly-β-hydroxy butyrate-co-β-hydroxy valerate (PHBV). Nylon 2-nylon 6 is another example of biodegradable polymers.

The monomers present in the polymer are melamine and formaldehyde.

Different types of polymers have different intermolecular forces of attraction. Elastomers or rubbers have the weakest while fibres have the strongest intermolecular forces of attraction. Plastics have intermediate intermolecular forces of attraction. Hence, the increasing order of the intermolecular forces of the given polymers is as follows:

1. Buna - S < polythene < Nylon 6, 6.
2. Neoprene < polyvinyl chloride < Nylon 6.

The names and structures of monomers are:
Neoprene is known as polychloroprene.

The names and structures of monomers are:Buna-S is known as butadiene-styrene copolymer.

Polymers whose repeating structural units are derived from only one type of monomer units are called homopolymers, e.g., PVC polyethene, PAN, teflon, polystyrene, nylon- 6 etc. Polymers whose repeating structural units are derived from two or more types of monomer molecules are copolymers, e.g., Buna-S, Buna-N, nylon-66, polyester, bakelite.

Addition polymers: Polyvinyl chloride, Polythene.
Condensation polymers: Terylene, bakelite.

The polymers which can be produced by biological system such as micro organisms, plants or animals. They can also be chemically synthesized. These are biodegradable and are from renewable sources. They act as stabalizers, thickness, binders, lubricants, etc.
e.g PHBV and Nylon-2–Nylon-6.

Nylon.

Weak intermolecular forces are present between the polymeric chains in neoprene; thus, it is an elastomer.

Proteins.

Homopolymer.

6, 6 means the number of carbon atoms in the monomers of Nylon-6, 6.

The two molecules combine to make nylon-6, 6, each contains 6 carbon atoms.

The process of formation of polymers from the respective monomers is called polymerization.

The polymer formed by the polymerization of a single/same monomeric species is known as Homopolymerisation.

Polymers which undergo bacterial degradation in the environment and are thus ecofriendly.

buna-S, buna-N, neoprene.

Monomer of PVC is vinyl chloride:

It is a copolymer, since, its repeating structural unit is derived from two types of monomer units, i.e., A and B.

Proteins are also like polyamides. Proteins and polyamide both contains amide linkages.

This is a type of chain growth polymerisation.

Organic compounds which when added to plastics make them soft and workable are called plasticisers. Examples are di-n-octylphthalate, tricresyl phosphate, etc.

The commercial name of PMMA (polymethylmethacrylate) is perspex. It is used as a substitute of glass. It is used for making lenses, transparent domes, aircraft windows and sky lights.

It is a cross linked polymer, since the various polymer chains are joined together to form a three-dimensional network structure (giant molecule).

Neoprene and teflon are addition polymers.

PVC (polyvinyl chloride).

Terylene or dacron.

Phenol and formaldehyde.

Natural rubber.

Polythene.

Polymers possessing amide linkages are important examples of synthetic fibres and are termed as nylons strong intermolecular forces like hydrogen bonding, lead to close packing of chains that imparts crystalline character.

Polymers which are formed by repeated addition of monomer molecules containing double and triple bonds are called addition polymers. Examples are polythene, PVC, PAN, PMMA, etc.

Rubber gets cross-linked through —S—S— bonds and becomes hard on vulcanisation.

The cis-polyisoprene molecule consists of various chains held together by weak van der Waals interactions and has a coiled structure. Thus, it can be stretched like a spring and exhibits elastic properties.

The monomers present in the polymer are melamine and formaldehyde.

Pure monomers are required because even the traces of impurities may act as initiators which lead to the formation of polymers of small chain lengths.

Enzymes are biocatalysts. They are basically proteins thus they are also considered as polymer.

Melamine and formaldehyde are starting materials for this intermediate. Its polymerisation gives melamine formaldehyde polymer.

Nylon-6,6.

The cis-polyisoprene molecule consists of various chains held together by weal vander Waals interactions and has a coiled structure. Thus, it can be stretched like a spring and shows elastic properties.

Novolac is a straight chain linear polymer but bakelite is cross linked.

Rubbers are stretched on application of force and come to its original position after the force is removed. Therefore, these are called elastomers.