Structural isomers are molecules that have the same chemical formula but different structures and chemical properties. For example, n-pentane (CH3CH2CH2CH2CH3) boils at 36.5 oC, but neopentane (C(CH3)4) boils at 9.5 oC. Explain why these two compounds have different boiling points.

Neopentane (C(CH3)4) have a lower a lower boiling point than n-pentane (CH3CH2CH2CH2CH3) because of it branched chain.

Explanation:

Structural isomers are compounds that have the same molecular or chemical formula but have different arrangement of atoms in space. The connectivity of the atoms differs for this compounds but they possess the same molecular formula. An example of structural isomers are butane and methyl propane. Usually, as the number of carbon increases for alkane the number of isomers also increases.

Since Isomers are different compound they are bound to have different characteristic both in melting and boiling points. Generally, straight chained isomers have higher boiling points than branched chain isomers.

n-pentane (CH3CH2CH2CH2CH3) is a straight chained isomer while neopentane (C(CH3)4) is a branched chain isomer.  Neopentane (C(CH3)4) have a lower a lower boiling point than n-pentane (CH3CH2CH2CH2CH3) because of it branched chain.