Methane VSEPR

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Marni Kahn 1A
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Methane VSEPR

Postby Marni Kahn 1A » Wed Nov 13, 2019 1:50 pm

How are all of the bond angles of Methane, CH4, 109.5 degrees?

Kate Osborne 1H
Posts: 102
Joined: Fri Aug 30, 2019 12:16 am

Re: Methane VSEPR

Postby Kate Osborne 1H » Wed Nov 13, 2019 1:53 pm

Because areas of electron density should be spread as far apart as possible and actual molecules do not exist in 2D, bond angles of 109.5 allow this to occur.

Shutong Hou_1F
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Re: Methane VSEPR

Postby Shutong Hou_1F » Wed Nov 13, 2019 3:16 pm

In order for the amount of repulsion to be minimized, the distance between bonding pair should be maximized, that is, keeping the bonding regions of electrons as far apart from each other as possible. Unlike Lewis structure that is 2-dimensional, VSEPR model is actually 3-D, allowing bonding regions of electrons to be distributed equally in 3 dimensions, in order to minimize the amount of repulsion. Therefore, after symmetrical distribution of bonding regions of electrons in 3 dimensions, the bond angels are all 109.5 degrees.

Matt Sanruk 2H
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Joined: Wed Sep 18, 2019 12:21 am

Re: Methane VSEPR

Postby Matt Sanruk 2H » Wed Nov 13, 2019 3:21 pm

Where did they get the number 109.5 from?

Victoria Otuya 4F
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Joined: Wed Sep 18, 2019 12:21 am

Re: Methane VSEPR

Postby Victoria Otuya 4F » Wed Nov 13, 2019 8:12 pm

Matt Sanruk 4F wrote:Where did they get the number 109.5 from?

I think they got the number from experimental observation and calculations.

Matt Sanruk 2H
Posts: 131
Joined: Wed Sep 18, 2019 12:21 am

Re: Methane VSEPR

Postby Matt Sanruk 2H » Wed Nov 13, 2019 9:13 pm

Oh yeah I see. Theres a complicated 15 minute video on youtube with obscure numbers.

Vicki Liu 2L
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Joined: Sat Aug 24, 2019 12:15 am

Re: Methane VSEPR

Postby Vicki Liu 2L » Wed Nov 13, 2019 9:22 pm

The 109.5 degree bond angles correspond to a tetrahedral structure. This is the molecular shape for CH4 and all other molecules with 4 bonding electron pair regions.

ABombino_2J
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Re: Methane VSEPR

Postby ABombino_2J » Thu Nov 14, 2019 3:19 pm

In 3-d Space when all the H atoms are equally spaced from C and when all the H atoms are as far apart as possible, the angle of the H-C-H bonds are approximately 109.5 degrees.


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