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Diamond v graphite Diamond and graphite are very different materials but are both made out of carbon atoms. Compare diamond and graphite by cutting up the statements and putting them in the correct place on the table. Diamond Graphite What does it look like? Is it a conductor or an insulator? How are the carbon atoms bonded? Density Does it conduct electricity? What is it used for? How was it formed naturally? How is it manufactured? © www.teachitscience.co.uk 2015 23739 Page 1 of 3 Diamond v graphite 2.2 g / cm 3 Yes 3.5 g / cm 3 No Each atom forms four strong bonds. The bonds are covalent (atoms share electrons). There are 100 million million million carbon atoms in a small diamond! Jewellery, oil-well drills, abrasives, cutting tools Each atom forms three strong covalent bonds in the same layer and one weak bond to an atom in another layer. An insulator An ohmic conductor (in one plane only) Pencil ‘lead’, as a lubricant in oil, furnace linings, electrodes, neutron moderator in nuclear power stations Formed in layers (like the layers of an onion) from carbon atoms in the magma below the earth’s crust. They are pushed up within volcanoes to the surface. Formed from plants that grew and died 200 - 300 million years ago. The plant remains were buried by new layers of rock which squeezed water out. As the carbon was pressed towards the core of the earth it grew hotter and layers formed. Made in industry by passing an electric current through a mixture of coal and silica. See-through, colourless, hard crystals Made in the lab by heating charcoal to 1650 oC at a pressure of 5 GPa for several minutes. Black, smooth, slippery © www.teachitscience.co.uk 2015 23739 Page 2 of 3 Diamond v graphite Teaching notes Differentiation Depending on ability give students a table with some of the boxes already filled in. Give most able students the table without the statements and ask them to research and fill in the table themselves. Add a column for graphene and ask students to research this as well. Extension BBC Bitesize is good starting point for information on the allotropes of carbon (link available at time of publishing). www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_gateway/che mical_economics/nanochemistryrev1.shtml Answers What does it look like? Is it a conductor or an insulator? How are the carbon atoms bonded? Density Does it conduct electricity? Diamond See-through, colourless, hard crystals Graphite Black, smooth, slippery An ohmic conductor (in one plane only) An insulator Each atom forms four strong bonds. The bonds are covalent (atoms share electrons). There are 100 million million million carbon atoms in a small diamond! 3.5 g / cm 3 Each atom forms three strong covalent bonds in the same layer and one weak bond to an atom in another layer. 2.2 g / cm 3 No Yes Jewellery, oil-well drills, abrasives, cutting tools Pencil ‘lead’, as a lubricant in oil, furnace linings, electrodes, neutron moderator in nuclear power stations How was it formed naturally? Formed in layers (like the layers of an onion) from carbon atoms in the magma below the earth’s crust. They are pushed up within volcanoes to the surface. Formed from plants that grew and died 200 - 300 million years ago. The plant remains were buried by new layers of rock which squeezed water out. As the carbon was pressed towards the core of the earth it grew hotter and layers formed. How is it manufactured? Made in the lab by heating charcoal at 1650 oC and 5 GPa for several minutes. Made in industry by passing an electric current through a mixture of coal and silica. What is it used for? © www.teachitscience.co.uk 2015 23739 Page 3 of 3