polar and nonpolar

(Polar molecules, Non-polar molecules, etc.)

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Cavalli_1H
Posts: 92
Joined: Thu Sep 19, 2019 12:15 am

polar and nonpolar

Postby Cavalli_1H » Sun Nov 17, 2019 8:48 am

can someone explain the 'cis' and 'trans' that he used to describe polar and non polar molecules? what does this have to do with 'preferential interactions'?

Kehlin Hayes 4C
Posts: 50
Joined: Wed Sep 18, 2019 12:17 am

Re: polar and nonpolar

Postby Kehlin Hayes 4C » Sun Nov 17, 2019 9:54 am

Cis means that the dipole moments of that molecule are on the same side which makes it polar, enabling it to form interactions with other polar molecules. Trans means the dipole moments are on opposing sides of the molecule cancelling out making the molecule nonpolar, this would prevent the molecule from forming ionic interactions. Just a rough understanding

Sofia Barker 2C
Posts: 101
Joined: Wed Sep 18, 2019 12:21 am

Re: polar and nonpolar

Postby Sofia Barker 2C » Sun Nov 17, 2019 11:31 am

"Cis" refers to a molecular structure in which two of the same atoms lie on the same side / plane of a molecule. The dipole moments of these atoms combine and make the molecule polar overall.
"Trans" refers to a molecular structure in which two of the same atoms are on opposite sides of a molecule. The dipole moments of these atoms cancel out because they oppose each other, making the molecule nonpolar overall.
Certain molecules tend to prefer to form either a cis or trans structure. Generally, a trans structure is more stable because the atoms are further apart, reducing repulsion.

Gabriella Bates 2L
Posts: 113
Joined: Thu Jul 11, 2019 12:15 am

Re: polar and nonpolar

Postby Gabriella Bates 2L » Sun Nov 17, 2019 11:38 am

I believe that the example of the cis and trans molecule served as an example of how two molecules with the same molecular formula but different arrangements can be either polar or non polar, depending on whether the dipole moments cancel. Since the cis molecule had the Cl atoms on the same side of the molecule, the dipole moments don't cancel and the molecule is polar, while the opposite is true for the trans molecule where the Cl atoms are on different sides of the molecule. However, the terms "cis" and "trans" themselves likely will be unimportant on the test itself.


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