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Alkenes for AQA GCSE Chemistry

Alkenes

This page covers the following topics:

1. Formulae and solubility of alkenes
2. First four alkenes
3. Molecular formula of alkenes

Alkenes are unsaturated hydrocarbons, meaning that there is a C=C bond present. They, like alkanes, are non polar molecules so are relatively insoluble in water.

Formulae and solubility of alkenes

The first 4 alkenes are slightly different to the first 4 alkanes as there MUST be a C=C bond.

First four alkenes

Molecular formula shows the number and type of atoms present in a molecule, remember that for alkenes they will follow the general formula from before.

Molecular formula of alkenes

1

What is the molecular formula of ethene?

Cโ‚‚Hโ‚„

What is the molecular formula of ethene?

2

What is the name of the 4th alkene?

pentene

What is the name of the 4th alkene?

3

How many structural isomers are there for butene? Draw structural formulas for these compounds.

image

How many structural isomers are there for butene? Draw structural formulas for these compounds.

4

What is the name of the alkene with the shortest possible carbon chain (the first alkene)?

Ethene, methene is not possible as there must be two carbons for a C=C bond.

What is the name of the alkene with the shortest possible carbon chain (the first alkene)?

5

What is the molecular formula for propene?

Cโ‚ƒHโ‚†

What is the molecular formula for propene?

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