(a) What is diamond? Of what substance is diamond made?
(b) Describe the structure of diamond. Draw a simple diagram to show the arrangement of carbon atoms in diamond.
(c) Explain why, diamond has a high melting point.
(d) State any two uses of diamond.
(a) Diamond, which is a colourless and transparent substance, is an allotrope of carbon. It is the hardest natural substance known. Diamonds are purely made of carbon and the symbol is C. When we burn diamond in oxygen, only carbon dioxide is evolved showing that diamond is made up of carbon.
(b) A crystal of diamond is a molecule of carbon atoms in which each carbon atom is connected to four other carbon atoms by strong covalent bonds forming a regular tetrahedron. As the carbon atoms are held together firmly by covalent bonds, diamond forms a very rigid structure.
The arrangement of carbon atoms in a diamond crystal is shown below:
(c) Diamonds have a very high melting point, as a huge amount of heat energy is required to break the strong covalent bonds in one crystal of a diamond. The melting point of diamonds is above 3500o C.
(d) Uses of diamonds:
(i) As diamonds have an extraordinary shine, they are used in making jewellery.
(ii) Diamonds, due to their hardness, are used in instruments like glass cutters, grinders. They are also used as abrasives for polishing.