Help understanding a lab - intermolecular bonding

In summary, the experiment showed that there is a difference in the depth of the vortex between water (hydrogen bonding) and the other two liquids. It is not clear why this is the case, but it may be due to the strong forces involved. Finally, it is time for bed!
  • #1
Jchem
28
0
Hello, I have done an experiment and I am having trouble explaining why certain things happen.

The topic is intermolecular bonding. I used three liquids, each is composed of different types of bonds.

liquid 1) Hydrogen bond
liquid 2) bonding due to dipole forces
liguid 3) bonding due to Van der Waals forces

Basically I take a liquid, put it in a cup and stir it really fast. I record the depth of the maximum vortex and the amount of time that it lasts.

Then do the same with the other two liquid. (same amount, same container).


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Now, I have 3 different values for the amount of time the vortex lasts, and I'm trying to understand why (in terms of intermolecular bonding). The answer that comes to mind is viscosity, but it is nowhere in the course.. so I don't think that's what I'm supposed to be looking for.

My second question is why is water (hydrogen bonding) so much different than the other two in terms of the depth of the vortex?

I know that hydrogen bonding is the strongest, but I'm not sure how that piece of information applies to the vortex.. as no bonds are being broken.



thanks for any help
 
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  • #2
Am I to assume that the liquid that hydrogen bonds has a deepest vortex?

The Bob (2004 ©)
 
  • #3
EDIT: Ok something is wrong here.. so I'm doing the experiment again.

I'll post the results as soon as I'm done
 
Last edited:
  • #4
Jchem said:
thanks for the quick response :smile:


......Depth of vortex.....Time votex lasted

Vander waal ... 2.5 cm.......9s.....
dipole......(.5 cm)......1s...
Hydrogen Bond:...2.2......12s...


and I'm not sure about my results (although I've done them several times) because question 2 asks why the water (hydrogen bond) is so different in terms of depth of vortex and time... but it isn so different.. its just slightly different.
Are you sure about these results? I only ask because I would expect the hydrogen bonding to cause the biggest vortex and but also to be the first to stop, which goes against what you have said.

The explanation is that the strong forces would cause the molecules to get pulled to one side more (so big vortex) but also because of the forces it would slow down fastest because the pull would do that. However it could be that the attractive forces cause the molecule to pull against each other and this would suggest a smaller vortex and a longer time to settle because the molecules are being pulled by each other more than in van der Waal's.

The Bob (2004 ©)

P.S.
Jchem said:
dipole...(.5 cm)

Is that 0.5cm or what?
 
  • #5
yes that is 0.5 cm
 
  • #6
Jchem said:
yes that is 0.5 cm
It is intersting. I would say that the dipole is the intermediate force and so is not at one end of the spectrum. This means will give the result it does. The other two are at opposite ends and so act in similar ways (e.g. hydrogen bonds are strong so attract more than van der Waal's but moving act in similar ways).

The idea is in my head but I do not have the time (my dad's faylt) to write it down. Also some other people might give me some inspiration.

The Bob (2004 ©)

P.S. Time for bed :smile:
 

Related to Help understanding a lab - intermolecular bonding

What is intermolecular bonding?

Intermolecular bonding refers to the attractive forces that exist between molecules. These forces are weaker than chemical bonds but play a crucial role in determining the physical properties of substances, such as melting and boiling points.

What are the different types of intermolecular bonding?

There are three main types of intermolecular bonding: hydrogen bonding, dipole-dipole interactions, and London dispersion forces. Hydrogen bonding occurs when a hydrogen atom is bonded to a highly electronegative atom, such as oxygen or nitrogen. Dipole-dipole interactions occur between polar molecules, where one end of the molecule has a slightly positive charge and the other end has a slightly negative charge. London dispersion forces are weak forces that exist between all molecules, caused by temporary imbalances in electron distribution.

How do intermolecular bonds affect the properties of a substance?

Intermolecular bonds can affect a substance's melting and boiling points, as well as its viscosity, surface tension, and solubility. Stronger intermolecular bonds result in higher melting and boiling points, while weaker bonds result in lower melting and boiling points. Additionally, substances with stronger intermolecular bonds tend to have higher viscosity and surface tension, and are less soluble in polar solvents.

How can intermolecular bonding be determined in a lab?

There are several experimental methods that can be used to determine the type and strength of intermolecular bonds present in a substance. These include measuring physical properties such as melting and boiling points, using spectroscopic techniques such as infrared spectroscopy, and performing chemical tests to identify specific functional groups that are involved in intermolecular bonding.

How does understanding intermolecular bonding help in practical applications?

Understanding intermolecular bonding is essential in fields such as material science, drug design, and chemical engineering. It allows scientists to predict and control the physical properties of substances, such as how they will interact with other molecules or substances. This knowledge is crucial in developing new materials, designing effective drugs, and optimizing industrial processes.

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