Monthly Archives: June 2010

CHM 110: Grades updated

CHM 110- students:

If you’re in section 1, you may view your lab average (and your updated course average) on [Desire2Learn].  If you are in section 2, I will post your lab averages as soon as I receive them  from Mr. Sneeringer.

Also, remember that CHM 110 lecture will not meet on Thursday morning (lab is unaffected).  If you have any questions about the final, please drop by the office or leave a comment on this post.

(If there are any CHM 100 students reading this post, CHM 100 lecture meets as usual on Thursday!)

Remember to bring a calculator with good batteries to the final on Friday!

CHM 110: Some example molecules from 6/16/10

Here’s formaldehyde.  You can see the trigonal planar structure clearly.  In some of these images, electrostatic potential is indicated with blue (for negative) and red (for positive) to show the polarity of these molecules.  Formaldehyde is a polar molecule.

Formaldehyde - with ESP shading

Take a look at the pyramidal shape of ammonia.  Its nitrogen atom is the top of the pyramid, while its hydrogen atoms form the base.  Ammonia is a polar molecule.

Ammonia - with ESP shading

Ammonia - with ESP shading

Water is a bent molecule, which gives the molecule a hydrogen “side” and an oxygen “side”.  This makes the molecule polar.

Water - with ESP shading

Water - with ESP shading

Difluoromethane is a molecule that, at first glance, may appear nonpolar.  It has two hydrogen atoms and two fluorine atoms, but their tetrahedral arrangement around the central carbon atom makes the molecule have a hydrogen “side” and and fluorine “side”.

Difluoromethane

Difluoromethane

Since fluorine atoms are very electronegative, their arrangement makes difluoromethane a polar molecule.

Difluoromethane - with ESP shading

Difluoromethane - with ESP shading