Instantaneous Dipoles

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Ashley Lopez 3J
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Joined: Wed Sep 30, 2020 10:06 pm

Instantaneous Dipoles

Postby Ashley Lopez 3J » Sun Nov 22, 2020 10:01 pm

Why are two nearby rod-shaped molecules stronger than when there are two nearby spherical molecules?

Savana Maxfield 3F
Posts: 175
Joined: Wed Sep 30, 2020 10:00 pm

Re: Instantaneous Dipoles

Postby Savana Maxfield 3F » Sun Nov 22, 2020 10:05 pm

I believe it is because rod-shaped have more contact surface area when nearby, so this means more surface area for IMFs and attractions.

Thomas Gimeno
Posts: 79
Joined: Wed Sep 30, 2020 9:49 pm

Re: Instantaneous Dipoles

Postby Thomas Gimeno » Sun Nov 22, 2020 11:39 pm

If its rod shaped then either end of the rod is likely partially charged and another charged rod can line up antiparallel making the dipole moment at either end of each particle very close to the dipole moments on the other particle. This means that both dipole moments on both molicules are interacting to hold the molecules together. Spherical molecules on the other hand will have dipole moments on either end of the sphere. This means that when two of the molecules interact, only one of the dipole moments on wither molecule will interact making the overall interaction weaker than if it had been between two rod shaped molecule.

Ayesha Aslam-Mir 3C
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Re: Instantaneous Dipoles

Postby Ayesha Aslam-Mir 3C » Mon Nov 23, 2020 1:07 am

Thomas Gimeno wrote:If its rod shaped then either end of the rod is likely partially charged and another charged rod can line up antiparallel making the dipole moment at either end of each particle very close to the dipole moments on the other particle. This means that both dipole moments on both molicules are interacting to hold the molecules together. Spherical molecules on the other hand will have dipole moments on either end of the sphere. This means that when two of the molecules interact, only one of the dipole moments on wither molecule will interact making the overall interaction weaker than if it had been between two rod shaped molecule.


This is a really good explanation, but to simplify it just comes down to the points of contact; if you put a pen and a pen together, they meet at more points than if you put two basketballs against one another. That surface area meeting allows for more dipole moments due to interaction between parts of that molecule.

Lauren Sarigumba 1K
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Re: Instantaneous Dipoles

Postby Lauren Sarigumba 1K » Mon Nov 23, 2020 1:32 am

Rod-shaped molecules have a greater surface area than spherical molecules, even though both molecules have the same chemical formula. Because of this characteristic, there are more opportunities for a rod-shaped molecule to have induced dipole-induce dipole interactions than spherical-shaped molecules. Ultimately, these rod-shaped molecules will have greater induced dipole-induced dipole intermolecular attractions than spherical-shaped molecules do.

Madeline Ogden 3B
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Re: Instantaneous Dipoles

Postby Madeline Ogden 3B » Mon Nov 23, 2020 3:09 pm

This is due to the fact that the rod shaped molecules will have a higher level of surface area touching than the two spherical molecules. The way I like to remember it is this: if someone asked you to hold a beach ball in your hand it would be much harder than trying to hold a baseball bat due to the fact that your hand has more contact (surface area) touching the object. Therefore it will be easier to knock the ball out of your hand than the bat (or in the case of the molecules, it will be easier to break the bond between the two spherical ones than the rod shaped ones.)


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