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how do the boiling/melting pts compare between equivalent alkane alkene alkynes?
I got confused on this topic.
Here are the reasoning. TPR says, branching will make it harder to stack so increase in bp and decrease in mp. But in Wade, branching will lead to a more compact 3D shape therefore, decrease in bp and increase in mp. Can someone help clear this up? Thanks.
The more branching, the lower the boiling boiling point and melting point (not sure if there was a typo in TPR or what). The reason that boiling point decreases in terms of Wade's explanation is because the compact shape leads to less available surface area for van der Waals forces to interact. Therefore, less intermolecular forces equate to a lower boiling point.
does that make sense?
Thanks, that makes sense. There was a typo in what I put. It should have read, "TPR, branching: lowers bp and mp" because of the decreased surface area, like what you said.
But it Wade, it says that the compact/packing shape will cause a higher mp. So will the mp increase or decrease? It makes sense that since there is less interaction, less energy is needed to break the bonds so lower mp. But it also makes sense that if they are can pack into a solid easier, the melting point would be higher (Wade).
Thanks
MP is decreased as well. The reasoning you said about mp decreasing is correct
This is from Wade.
this will help explain further: http://forums.studentdoctor.net/showpost.php?p=2877597&postcount=3
thanks for the link, I also found this post. http://forums.studentdoctor.net/showpost.php?p=1287140&postcount=17
how do the boiling/melting pts compare between equivalent alkane alkene alkynes?