shape of molecule/intermolecular forces

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Katherine Wu 1H
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shape of molecule/intermolecular forces

Postby Katherine Wu 1H » Mon Nov 11, 2019 1:43 pm

Account for the following observations in terms of the type and strength of the type and strength of intermolecular forces.
(c) The boiling point of pentane, CH3(CH2)CH3, is 36.1 degrees celsius, whereas that of 2,2-dimethylpropane (aka neopentane) C(CH3)4 is 9.5 degrees celsius.

The answer says that pentane is a linear molecule while dimethylpropane is a compact, spherical molecule. How do you find the shape of the molecules?

Rachel Yu 1G
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Re: shape of molecule/intermolecular forces

Postby Rachel Yu 1G » Mon Nov 11, 2019 1:57 pm

Part of the molecules in parentheses aren't part of the main carbon chain. With this information, you can tell that pentane has a longer, flatter molecular shape compared to 2,2-dimethylpropane, which doesn't form a carbon chain, but rather four C-C bonds around the main carbon atom.

Katherine Wu 1H
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Re: shape of molecule/intermolecular forces

Postby Katherine Wu 1H » Mon Nov 11, 2019 2:52 pm

what does the molecular structure of dimethylpropane look like? I have a hard time visualizing it.

Julie Park 1G
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Re: shape of molecule/intermolecular forces

Postby Julie Park 1G » Tue Nov 12, 2019 12:55 am

Neopentane's structure consists of four C atoms attached to a center C atom in a "+" shape, with CH3 stemmed out from each of the four surrounding C atoms. The structure is symmetrical and kind of spherical.

I recommend looking at the imagine on the right-hand side of this page: https://en.wikipedia.org/wiki/Neopentane


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