Isomers of pentane C5H12
The chemical formula for pentane is C5H12.Pentane has 3 structural isomers.
1. pentane also known as n-pentane
2. 2-methyl butane also known as isopentane
3.2, 2-dimethyl propane also known as neopentane
The structure of isomers are as follows
Properties of pentane isomers:
The two branched isomers are more stable than pentane, which means that they have lower heat of formation and heat of combustion.
Typically, physical properties like melting point and boiling point temperatures are the properties that are different for isomers. Chemical properties are the same because there are the same number and kind of atoms in each isomer. The different isomers have different structures which affect the physical properties.
Normal pentane (C5H12) (straight chain molecule) has a bp of 309.4 K
2,2-dimethylproprane (C5H12) (isomer of pentane, but not a straight chain molecule - it is branched) has a bp of 282.7 K
The intermolecular forces of attraction between the normal pentane molecules are greater than the ones between 2,2-dimethylpropane molecules so the bp is higher. The attractive forces have to be overcome to boil the liquid.
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