Write two points of difference in the structures of diamond and graphite. (b) Explain why, graphite can be used as a lubricant but diamond cannot. (c) Explain why, diamond can be used in rock drilling equipment but graphite cannot. (d) State one use of diamond which depends on its 'extraordinary brilliance' and one use of graphite that depends on its being 'black and quite soft'.

• (i) In diamond, carbon atoms are linked to four other carbon atom In graphite, carbon atom is joined to only three other carbon atoms.

(ii) In diamond, crystal has tetrahedral arrangement In graphite, crystal has a hexagonal ring structure.

• Graphite can be used as lubricant because of its
• Diamond can be used as rock drilling equipment because of its hardness It has a rigid structure.
• Diamonds are used for making jewellery Graphite is used for making pencil leads.