SUBJECTS: Science
YEARS: 9–10
Have you seen the model of long-chain carbon molecules first developed by Friedrich August Kekulé?
This model enabled chemists to make a great leap forward in their understanding of the structure of organic molecules.
See how to represent the structure of methane, ethane, propane, butane and octane.
Find out how to rearrange atoms in the model to identify isomers (compounds with the same chemical formula).
Things to think about
- 1.If you were to represent (show) a compound such as carbon dioxide, how would you do it? What models have you seen that represent the structure of chemical compounds? What do these models usually include? How are the bonds between atoms shown in these models?
- 2.Check out how many carbons there are in a molecule of methane, ethane, propane, butane and octane. Spot what tricky cases the model helped to explain. Watch for how the carbon atoms in a molecule can be rearranged.
- 3.Draw straight chain 'ball and stick' models of methane, ethane, propane, butane and octane. Include each one's chemical formula. Do you notice a pattern in the chemical formulae? What is it?
- 4.
Methane, ethane, propane, butane and octane belong to a type of hydrocarbons called alkanes. They can be produced by separating out compounds in the mixture of crude oil. Find out more about alkanes and how they are produced using fractional distillation.
Date of broadcast: 13 Aug 2001
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