Chemical Bonding Help (1 Viewer)

[sikeveo]

Not too sure on this question.

 

[Dreamerish*~]

Ethene: Has weak dispersion forces between the molecules, non-polar. It has a double bond which is very reactive which may have something to do with its low boiling point. (sorry!)

Ethane: Has a larger molecular mass than ethene, therefore more dispersion forces and a slightly higher melting point.

Ethanol: The OH^- groups enable hydrogen bonding between molecules. Hydrogen bonds are much stronger than dispersion forces, therefore the boiling point of ethanol is much higher.

I'm not 100% sure about the ethene-ethane comparison.

For intermolecular forces, see here.

 

[Jumbo Cactuar]

It has a double bond which is very reactive which may have something to do with its low boiling point. (sorry!)

It is purely that ethane is more of a fat bastard molecule than ethene.

Reactivity ... nice one

 

[sikeveo]

So just molecular mass? I'm not sure whether the examiner would accept your reason

 

[Dreamerish*~]

It is purely that ethane is more of a fat bastard molecule than ethene.

Reactivity ... nice one

Hahaha, I guessed that one.

What about the double bond? I had an impression that double bonds were harder to break...

 

[Skywalker]

True - but you're talking about intermolecular, not intramolecular forces here. The presence of the double bond wouldn't affect the boiling point because you're not breaking up the molecule.

Hence you go with the larger dispersion forces created by the larger molecular weight.