After the discovery of \({{\text{C}}_{60}}\), chemists discovered carbon nanotubes. Describe the structure and properties of carbon nanotubes.

Nanotechnology could provide new solutions for developing countries where basic services such as good health care, education, safe drinking water and reliable energy are often lacking. Discuss some of the potential risks associated with developing nanotechnology.

main cylinder is made only from carbon hexagons, with pentagons required to close the structure at the ends;

single or multiple walled tubes made from concentric nanotubes can be formed;

bundles of the tubes have high tensile strength;

other substances (elements, metal oxides etc.) can be inserted inside the tubes;

strong covalent bonding / no weak bonds;

behaviour of electrons depends on the length of a tube and hence some forms are conductors and some are semiconductors;

hazards associated with small airborne particles are not known / long term effects unknown / OWTTE;

may not be covered by current toxicology regulations (as properties depend on the size of the particle) / may be toxic / OWWTE;

human immune system may be defenceless against new nanoscale products / OWTTE;

(there may be social problems) as poorer societies may suffer as established technologies become redundant and demands for commodities change / OWTTE;

Candidates had considerable difficulty describing the structure and properties of carbon nanotubes and often speculated very vaguely on the impact of nanotechnology. Responses were often superficial.

Candidates had considerable difficulty describing the structure and properties of carbon nanotubes and often speculated very vaguely on the impact of nanotechnology. Responses were often superficial.