Pentane vs. 2-dimethylpropane

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Marina Souliman 1K
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Joined: Fri Apr 06, 2018 11:05 am

Pentane vs. 2-dimethylpropane

Postby Marina Souliman 1K » Sun May 20, 2018 2:04 pm

Can someone explain why pentane has a higher boiling point over 2-dimethylpropane? I need a little clarification about how the shape of the molecule plays into this.
Last edited by Marina Souliman 1K on Sun May 20, 2018 7:20 pm, edited 1 time in total.

victoriatanaka1C
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Joined: Fri Apr 06, 2018 11:05 am

Re: Friday Class

Postby victoriatanaka1C » Sun May 20, 2018 2:10 pm

In my notes, I wrote "instantaneous dipoles in two nearby rod-shaped molecules are closer and therefore stronger than those in two nearby spherical molecules." Pentane and 2, 2-Dimethylpropane have the same molecular formula but pentane is rod-shaped. This rod shape is stronger so it's harder to break apart, hence the higher boiling point.

Elena 1H
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Re: Pentane vs. 2-dimethylpropane

Postby Elena 1H » Sun May 20, 2018 10:54 pm

A rod shape is stronger than a spherical shape because a rod shape allows the positive and negative charges on the molecule to be closer together, since pentane is in a rod shape it has a higher melting point than 2-dimethylpropane

Alexandra Wade 1L
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Re: Pentane vs. 2-dimethylpropane

Postby Alexandra Wade 1L » Mon May 21, 2018 10:51 am

Pentane is ultimately able to have more van der waal interactions due to its rod shape creating a stronger "bond" between the two molecules so it takes more heat to break them apart.


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