[mehmetco]

Hi guys, I am having trouble with this chart.

http://slideplayer.com/slide/7839280/25/images/17/Are+polar+molecules+involved+molecules+and+ions+both+present.jpg

Can some one aditionally assist me in determining polarity and non-polarity. I am currently taking CHEM 2, and I took CHEM 1 two years ago.

(mod edit to change the URI to the actual image)

[sjb]

Can you give an example of the difficulty you are having?

[mehmetco]

Can you give an example of the difficulty you are having?

Well so I am having difficulty with something like this:

Determine which intermolecular forces are the dominant (strongest) forces for a pure sample of each of the following molecules by placing the molecules into the correct bins.

BIN 1) Dispersion Forces   BIN 2) Dipole-dipole   BIN 3) H-Bonding

We have Xe, CH4, H2S, CH2CL2, CH3COOH, NH3

I got the answer correct due to some help, but I do not know where to start. All I know is, Xe has dispersion forces. I thought that chart would be helpful, but when it says "Are ions present" I don't know if I just need to memorize the polyatomic ions, or what.

[mehmetco]

Can you give an example of the difficulty you are having?

I believe the root cause is because I can't determine if something is polar or non-polar

[wildfyr]

Essentially there are two considerations: symmetry, and the presence of hydrogen bonding. Non-symmetrical molecules will have stronger dipole interactions, and hydrogen bonding will usually overcome dipole or dispersion forces.

[mehmetco]

Essentially there are two considerations: symmetry, and the presence of hydrogen bonding. Non-symmetrical molecules will have stronger dipole interactions, and hydrogen bonding will usually overcome dipole or dispersion forces.

Do you think it would be useful to start to draw the lewis dot structure, as i did in chem 1, just to refresh myself?

[mehmetco]

I am having trouble understanding polarity, so I can determine which molecules can dissolve which. Additionally, I thought the textbook would help, and I was wrong.

Can anyone reference me any information in which I can gain a better understanding so I can have full comprehension on the chapter regarding Solutions?

Thank you.

[wildfyr]

Yes, drawing the lewis structure is always helpful. It should assist in your ability to see symmetry.

[Babcock_Hall]

Drawing the Lewis structures makes it easier to see possible hydrogen bonding.