P roperties
Chemical/Physical Properties
The boiling points for benzene is around 80.1 degrees celcius. This is much different than the alkanes, alkenes, and alkynes. Those molecules have relatively low boiling points due to their structure being non-polar and their intermolecular forces only being weak London Dispersion Forces. Benzene, along with these molecules, also only has LDF intermolecular forces; whats different is that benzene acts like it is saturated (when it has pi bonds) due to its delocalized electrons. These delocalized electrons result in an large increase of the probability of temporary dipoles, which results in a very strong LDF intermolecular force between benzene molecules. This strong force is what makes its boiling point relatively high.
The melting point for benzene is around 5.5 degrees celcius. This is much differnet than alkanes and alkenes (who have relatively low melting points) for the same reason why benzene has a relatively high boiling point. The strong LDF intermolecular forces make it so that more energy has to be added in order to break the forces holding the benzene molecules together as a solid.
Since solubility is based on the similarities in intermolecular forces of the solute and the solvent, benzene is gerneally insoluble in water. This is due to water having LDF, Dipole-Dipole, and Hydrogen Bonding intermolecular forces, while benzene only has LDF intermolecular forces (although they are relatively strong). In terms of solubility with other benzene molecules, they are soluble. This is due to benzene molecules sharing the same intermolecular forces of LDF (only).
The density of benzene is consistent enough for them to be less dense than water (but much denser than most alkanes, alkenes, and alkynes), this is due to their weak intermolecular forces (but stronger LDF forces compared to most other hydrocarbons like alkanes) which make them less compact (less dense). Benzene's density is around 876 kg/m3.
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