Chemistry Chapter Preview- Macromolecules : Summary Mode

SUMMARY

 

A macromolecule is a large molecule made by joining together many small molecules.

A polymer is a long-chain macromolecule made by joining together many small molecules.

A monomer is the starting material for making a polymer.

Polymerisation is a reaction in which many small molecules (monomers) join together to make one large molecule.

Polymers are classified into two groups. These are addition polymers and condensation polymers.

Addition polymerisation is a reaction in which small molecules join together to for one molecule as the only product.

Condensation polymerisation is a reaction in which monomers join together to form polymers with the elimination of small molecules.

Two common examples of condensation polymers are nylon and terylene.

Chemistry Ch27. Macromolecules-summary

SYLLABUS

 

Describe the term macromolecule.

A macromolecule is a large molecule made by joining together many small molecules.

 


Describe the formation of poly(ethene) as an example of addition polymerisation.

The ethene molecules has a C = C double bond. During the polymerisation, the double bond opens. These open units join together to form a molecule of poly(ethene)

 


State some uses of poly(ethene) as a typical plastic.

Poly(ethene) is the most widely used plastic today. The uses include plastic bags, cling film for wrapping food, flexible water pipes, plastic bottles, plastic chairs and insulation around electrical wires.

 


Deduce the structure of a polymer from a given monomer and vice versa.

 


Describe nylon and terylene as condensation polymers.

Condensation polymerisation is a reaction in which monomers join together to form polymers with the elimination of small molecules. Two common examples of condensation polymers are nylon and terylene.

The repeat unit for nylon can be written as:

Chemistry Ch27. Macromolecules-summary-pic1

 

The repeat unit for terylene can be written as:

Chemistry Ch27. Macromolecules-summary-pic2

 


State some typical uses of man-made fibres such as nylon and terylene.

Nylon is made into fibres to make strong ropes and fishing lines, or woven into cloth to make nylon tents, parachutes and raincoats. Most zippers are made of nylon. Nylon is strong yet light, and can be stretched without breaking

Terylene is used to make clothes and sails.

 


Describe pollution problems caused by the disposal of non-biodegradable plastics.

All plastics produce carbon monoxide gas when they burn. In addition, PVC produces chlorine and nylon produces extremely poisonous hydrogen cyanide gas when burnt.

Plastics are resistant to corrosion and are described as being non-biodegradable as bacteria do not break them down naturally. Hence, discarded plastic objects pollute the environment.

To make plastic foam, chloroflurocarbons (CFCs) are used. These gases later escape from the plastic foam and enter the atmosphere. CFCs are greenhouse gases and contribute towards global warming.

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