Chemistry- Polymers and Giant Covalent Structures

Polymers and Giant Covalent Structures

In a polymer, lots of small units are linked together to form long molecules that has repeating sections. All the atoms in a polymer are joined by strong covalent bonds. Instead of drawing out a whole long polymer molecule, you can draw the shortest repeating section, called the repeating unit, like this:

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To find the molecular formula of a polymer, write down the moleula formula of the repeating unit in brackets, and put 'n' outside. The intermolecular forces betweent the polymers are larger than between simple covalent molecules, so more energy is required to break them. This means polymers are solid at room tempertaure. The intermolecular forces are still weaker than ionic or covalent bonds, so they generally have lower boiling points than ionic or giant molecular compounds.

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In giant covalent structures. all the atoms are bonded to eachother by strong covalent bonds. They have very high melting and boiling points as lots of energyis needed to break the covalent bonds between the atoms. They don't contain charged particles, so they do not conduct electricity- not even when molten (except for graphite). The main expamples are diamond and graphite which are both made from carbon atoms only, and silicon dioxide (silica).

Diamond:

Diamond has a giant covalent structre, made up of carbon…