This is a draft cheat sheet. It is a work in progress and is not finished yet.
Definitions
Homologous series |
A series of organc compounds having the same functional group and each successive member differs by CH2 |
Molecular formula |
Actual number of atom of each element in a molecule. Doesn't show the structure of a molecule |
Empirical formula |
The simplest whole-number ratio of atoms of each element in a compound |
Displayed formula |
Shows the relative positioning of the atoms and the bonds between them |
Structural formula |
Shows the arrangement of atoms in a molecule using the smallest amount of detail |
Skeletal formula |
Simplified organic formula- only showing functional groups and carbon skeleton |
Structural isomers |
Compounds with the same molecular formula and a different structural formula |
Radical |
An atom/group of atoms with an unpaired electron |
Homolytic fission |
When a covalent bond breaks and each of the bonded atoms takes one of the shared pair of electrons |
Heterolytic fission |
When a covalent bond breaks and one of the bonded atoms takes both of the electrons in the bond |
Curly arrows (in a reaction mechanism) |
Used to show the movement of electron pairs |
Electrophile |
A molecule that contains a partially positive atom or a positive ion |
Nomenclature of organic compounds
Identify the longest, continuous carbon chain containing a functional group. This forms the second part of the name of the compound |
Identify any side chains attached called alkyl groups. The alkyl group is added as a prefix to the name of the parent chain |
You need to number the carbon chain so that the side chain(s) is on the carbon atom with the lowest number. This number goes in front of the alkyl group |
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Alkanes
Alkanes are a homologous series made up of saturated hydrocarbons |
Each carbon atom is bonded to 4 other atoms by sigma bonds (single covalent bonds) |
Each bond angle around a single carbon atom is approximately 109.5 degrees |
The sigma bonds are rotational |
Properties of alkanes
As the length of the carbon chain increases, the boiling point increases as well. This is because as the chain length increases, there are stronger London forces. |
As the chain length increases, the surface area increases therefore more points of contact between molecules. This increases London forces. |
Branching decreases boiling point. This is because there are fewer points of contact between the molecules and weaker London forces |
Boiling point trend of alkanes
Methane |
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-162 |
Ethane |
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-89 |
Propane |
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-42 |
Butane |
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-1 |
Pentane |
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36 |
Hexane |
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69 |
Chemical reactions of the alkanes
Complete combustion of alkanes: alkanes burn completely in sufficient supply of oxygen to produce carbon dioxide and water |
Incomplete combustion of alkanes: alkanes burn in a limited supply of oxygen to produce water and carbin monoxide |
Alkanes reacting with halogens: occurs in the presence of UV light |
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