how do you know what the strongest intermolecular force present for a compound???

hydrogen bonding in water, pehaps? that is much stronger than london dispersion... if not, probably some other polar attraction...

 

oh sorry misunderstood the question

Edited March 19, 200916 yr by max.yevs
misunderstood the question

You will have to measure it, model it, discuss it and then accept that there is still a (small) error.

Intermolecular forces are hard to measure. Because there exist so many chemicals in the world, there is a big chance that there is no data from measurements.

I believe that models such as the UNIFAC model... UNIFAC models interactions from group contributions.

 

Did that answer the question? Please post a more detailed question if you want to know more.

Qualitatively for many compounds, IM forces can be guessed by considering the polarity of, and groups present in, the compound. Compounds with amine, hydroxyl or carboxyl groups tend to hydrogen bond, whereas entirely non-polar compounds may have only dispersion forces.

 

Quantifying it is, as the Cap'n said, is a more complicated issue but well worth pursuing.