Wednesday, March 9, 2011

Intermolecular Forces

Today was all about intermolecular forces. The first type is called a dispersion force. Dispersion forces are weakest type of intermolecular force, and it is present in every molecule. Dispersion Force also depends on the molar mass of a substance.

The second type of intermolecular force is Dipole forces. Every polar molecule has dipole forces. Since polar molecules have a negative and positive ends, dipole forces cause polar molecules negative ends to attract the positive ends of other molecules and then another molecule will attach and so on.

The third type of intermolecular force is Hydrogen Bond forces. Hydrogen Bonds are basically the same concept of dipole forces, where the negatives attach to the positives, but these forces are a lot stronger. However there is a catch, hydrogen bonds can only happen when a hydrogen bonds to a N, O, or F. These three atoms have the highest electronegativities, so they will create very very polar molecules. A great example of hydrogen bonds is H2O. The intermolecular force in water is great because of the hydrogen bonds. Because the forces are so great, it can cause water to stick together, or bead. These hydrogen bonds are the reason for these to events....


Today we also did a lab exploring the effects of intermolecular forces. These effects include...
-Evaporation Rates
-Capillary Action (A Liquids tendency to climb up the walls of a narrow column)
-Vortex Formation and Relaxation (The time it takes for a liquid to relax after swirling it)
-Viscosity (Resistance to flow)
-Surface Tension (Property shown by water in above photo of the water drops on the penny)
-Beading (Shown in the above picture of the water)

The homework for today is to keep up with the webassigns. There is a reading sheet due tomorrow and all the other HW WAs are due friday. The Lab is also due on friday

The next scribe is....STUART P. Good luck bud

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