4. Identify the reason for its use: (2)
(i)Graphite is used as crucibles
(ii) Diamond is used to cut glass.
(iii) Space shuttles, satellites are coated with
thin layer of gold.
Answers
Answer:
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Explanation:
(i) Graphite is a very stable allotrope of carbon but at a very high temperature it can be transformed into artificial diamond. ... Being resistant to chemicals and having a high melting point and also because it is a good conductor of heat, graphite is used to make crucibles.
(ii) Since diamonds are the hardest known substance having hardness set to 10, while glass which are used on windows have a hardness of 5.5. What this means is that any material which has hardness within a range from 5.5 to 10 can be used to cut glass.
(iii) The yellowish-gold color of the polyimide on the outside gives the satellite the appearance of being wrapped in gold. Multi-layer insulation is used on satellites primarily for thermal control and protects the delicate on-board instruments from the extreme temperatures of space.