Polarity

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Agustina Santa Cruz 2F
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Polarity

Postby Agustina Santa Cruz 2F » Fri Nov 20, 2020 2:58 pm

How can a molecule be made up of polar bonds but not be polar as whole molecule?

Chem_Mod
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Re: Polarity

Postby Chem_Mod » Fri Nov 20, 2020 3:20 pm

Lets look at a molecule like CF4. The bonds inside the molecule are polar due to the difference in electronegativity between C and F. But the molecule itself is non-polar because the dipoles cancel out (i.e. they are equal and opposite in magnitude). As you can see below we have a symmetrical arrangement of atoms of equal electronegativity.
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Austin Aldujaili 2D
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Re: Polarity

Postby Austin Aldujaili 2D » Fri Nov 20, 2020 3:26 pm

When determining polarity, it is important to look at not only the difference in electronegativity but also the shape of the molecule. When there are two or more polar bonds opposite of one another, I have always thought of it as like two people playing tug of war with electrons that have the same arm strength. In this case, arm strength is electronegativity and there is no movement of the electron rope if that makes sense.

George Cazares 1E
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Re: Polarity

Postby George Cazares 1E » Fri Nov 20, 2020 4:37 pm

A molecule made up of polar bonds can be nonpolar if the dipoles cancel due to its molecular shape. For example, in the trans-dichloroethene molecule, the dipoles are on the opposite side of the carbon going in two different directions, which causes the dipoles to cancel.

Joshua Eidam 2A
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Re: Polarity

Postby Joshua Eidam 2A » Sat Nov 21, 2020 12:20 am

I understand that if there are multiple polar bonds present, and their dipole moments are not canceling out, then the molecule is polar. But what exactly makes a certain molecule more polar than another? Does it have to do solely with the strength of the polar bonds or are there other factors that contribute to this?

Laura 3l
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Re: Polarity

Postby Laura 3l » Sat Nov 21, 2020 3:15 am

A molecule can be polar because of the dipoles occurring between each atom, but when all the atoms have the same "pull", electronegativity difference, they can cancel out resulting in the whole molecule to be nonpolar.

Kiyoka Kim 3C
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Re: Polarity

Postby Kiyoka Kim 3C » Sat Nov 21, 2020 3:28 am

If dipole moments occurring between atoms in a molecule cancel out, then you would say there is no net dipole moment making the molecule non polar.

Sejal Parsi 3K
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Re: Polarity

Postby Sejal Parsi 3K » Sat Nov 21, 2020 4:21 am

Thought there are dipole moments happening between atoms in a molecule, they can cancel out, making the molecule non polar.

Anna Yang 1A
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Re: Polarity

Postby Anna Yang 1A » Sat Nov 21, 2020 10:06 am

Dipole moments cancel when they are equal and opposite to each other. When polar bonds are in opposite directions though the bonds are polar themselves, they make the molecule as a whole non polar. CCl4 is an example as such as C-Cl bonds are polar themselves but because of the symmetry of its tetrahedral shape, they all cancel out to the make CCl4 molecule as a whole non polar.

Bella Bursulaya 3G
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Re: Polarity

Postby Bella Bursulaya 3G » Sat Nov 21, 2020 1:00 pm

There can be polar bonds, but if they all cancel each other out, overall the molecule will be nonpolar. It's like if you are pulling a wagon one way and your friend is pulling it the other way. You're pulling different ways but you cancel each other out and the wagon doesn't move.

David Y
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Re: Polarity

Postby David Y » Sun Nov 22, 2020 4:02 pm

The dipoles can cancel each other out in the compound

Jasmine Ho 3I
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Re: Polarity

Postby Jasmine Ho 3I » Sun Nov 22, 2020 4:09 pm

If all of the dipole moments cancel out (by being of the same magnitude and in exact opposite directions), then the molecule will be nonpolar.

DominicMalilay 1F
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Re: Polarity

Postby DominicMalilay 1F » Sun Nov 22, 2020 5:00 pm

Yes because the dipoles cancel

Brian Nguyen 2I
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Re: Polarity

Postby Brian Nguyen 2I » Sun Nov 22, 2020 9:55 pm

You can have a nonpolar molecule even if there are polar bonds due to the fact that the dipoles formed from polar bonds are cancelled out from the overall shape of the molecule.

rhettfarmer-3H
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Re: Polarity

Postby rhettfarmer-3H » Sun Nov 22, 2020 11:36 pm

yes, this is very common and it has to do with dipole movements. An easy one is C02. co bonds are polar bonds. but for co2 its two double bonds on either side of the c. Hence, they both move their dipole towards the c so the movement is actually counteracting each other and therefore, it is even and no it is not polar.

Jeremy Wei 2C
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Re: Polarity

Postby Jeremy Wei 2C » Mon Nov 23, 2020 5:00 pm

Polar bonds form due to the difference in electronegativities between the atom but these bonds can cancel out due to the orientation of the molecule as a whole.

Susan Chamling 1F
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Re: Polarity

Postby Susan Chamling 1F » Tue Nov 24, 2020 12:37 am

I think one method of figuring out if a molecule is polar or not, even when it has dipole forces, is to look at the molecule's structure and determine whether it has symmetry or not. If it has symmetry, in most cases it will not be polar, even when it has dipole forces, because they will cancel out.

Rose_Malki_3G
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Re: Polarity

Postby Rose_Malki_3G » Tue Nov 24, 2020 1:42 am

If the dipoles of the polar bonds cancel each other out, then the overall species would still be considered non polar.

Margaret Xu 3C
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Re: Polarity

Postby Margaret Xu 3C » Tue Nov 24, 2020 4:18 pm

A molecule can have polar bonds between atoms, but if they cancel out then there is no net dipole moment so the overall molecule isn't polar.

Ivy Tan 1E
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Re: Polarity

Postby Ivy Tan 1E » Tue Nov 24, 2020 5:49 pm

Hi!
If the polar bonds within the molecule cancel each other out, then the molecule as a whole will be nonpolar. For example, in CO2, the bonds between carbon and oxygen are polar because oxygen is more electronegative than carbon. However, the symmetrical shape of the molecule makes it nonpolar, since both polar bonds cancel each other out. Hope this was helpful!!

Lorraine Medina 3E
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Re: Polarity

Postby Lorraine Medina 3E » Tue Nov 24, 2020 7:04 pm

The dipole moments cancel out. Hope this helps!

Daniela_Martinez_3B
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Re: Polarity

Postby Daniela_Martinez_3B » Tue Nov 24, 2020 7:36 pm

if the dipole moments cancel out it's non-polar!

gabbi_r2C
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Re: Polarity

Postby gabbi_r2C » Tue Nov 24, 2020 7:43 pm

Basically, a molecule made up of polar bonds will only be nonpolar if the dipole moments of each polar bond cancel, meaning they are of equal magnitude and opposite direction.

derickngo3d
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Re: Polarity

Postby derickngo3d » Tue Nov 24, 2020 8:09 pm

Yes, the interaction of the polar bonds determines the polarity of the molecule. Hope this helps!

Binyu You
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Re: Polarity

Postby Binyu You » Sat Nov 28, 2020 11:22 pm

When the covalent bond is shared equality it means the molecule is non-polar. For example, a molecule contains only C and H are always non-polar. Also, if polar bonds can also be non-polar only if the dipole moments of each polar bond cancel, which means they have equal magnitude and is orienting in opposite direction.

Queena Chu 3E
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Re: Polarity

Postby Queena Chu 3E » Sat Nov 28, 2020 11:31 pm

If the polar bonds are symmetrically distributed, then the bond dipoles cancel out and a molecular dipole isn't created.

Veeda Khan 2E
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Re: Polarity

Postby Veeda Khan 2E » Sun Nov 29, 2020 5:27 am

If the molecule is symmetrical, the polar bonds can "cancel out".

Yolanda_Xing_3A
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Re: Polarity

Postby Yolanda_Xing_3A » Sun Nov 29, 2020 9:34 am

If the dipole moment cancel out each other, then the whole molecule is consider non-polar. Imagine each polar bond is a vector of force(this includes direction and magnitude) and picture whether they canceled each other out or not

Kandyce Lance 3E
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Re: Polarity

Postby Kandyce Lance 3E » Sun Nov 29, 2020 9:57 pm

Sejal Parsi 3K wrote:Thought there are dipole moments happening between atoms in a molecule, they can cancel out, making the molecule non polar.



Yes! that's true

Heidi Buri 2I
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Re: Polarity

Postby Heidi Buri 2I » Mon Nov 30, 2020 1:27 pm

Hi! A molecule can be made up of polar bonds but not be a polar molecule due to the arrangement of the atoms. A molecule can have a symmetrical arrangement of polar bonds. This symmetrical arrangement of polar bonds can make a molecule that has polar bonds but is not polar as a whole molecule.

Faith Lee 2L
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Re: Polarity

Postby Faith Lee 2L » Mon Nov 30, 2020 3:32 pm

As long as the polar bonds within the molecule "cancel out," the overall molecule will be nonpolar. Imagine the non-central atoms all pulling on the electrons of the central atom with equal strength, or the central atom pulling on the electrons of the non-central atoms with equal strength, in all directions :)


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