Giant Covalent Substances Flashcards
All 6 cards in this deck
What is a giant covalent (macromolecular) substance?
A huge lattice of many atoms joined throughout by strong covalent bonds.
e.g. diamond, graphite, silicon dioxideDescribe the structure of diamond.
Each carbon atom is covalently bonded to four others in a rigid three-dimensional giant lattice.
Describe the structure of graphite.
Each carbon atom is covalently bonded to three others forming layers of hexagonal rings, with weak forces between the layers and one delocalised electron per atom.
Why is graphite used to make electrodes?
Each carbon has one delocalised electron that is free to move through the structure, so graphite conducts electricity (and has a very high melting point).
Why is graphite used as a lubricant?
Its layers are held together by weak forces, so they can slide over each other.
Why is diamond used in cutting tools?
It is very hard, because every carbon is held by four strong covalent bonds in a rigid 3D lattice.