Ask A Scientist© Chemistry Archive

name         Kristin
status       student
age          16

Question -   I need help!!  ok a polar bond has a dipole dipole
attraction...so it has positive and negative end that attract to other
molecules..right?
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So far, so good.

 >so, what makes something like skim milk more
 >polar than something like half and half?

Um... who said that?  As solvent properties go, I'm not aware of any
measurements that find that skim milk is more polar than half and half.
Milk is an emulsion of fat in water.  (There are other components, such as
calcium, sugars, and proteins in the water phase as well, but we'll just
worry about the fat and water now.)  Water is a very polar molecule.  Fats
are not very polar.  The water environment that the sugars and proteins find
themselves in is probably about the same in skim milk and half and half;
there are just more fat globules in the half and half.  So half and half has
a higher proportion of nonpolar molecules and a lower proportion of polar
molecules than skim milk does.  If that means that the half and half is less
polar, so be it.

 > I know there's more water in
 > skim milk...but is it because of the hydrogen in the water...

The O-H bonds of water are polar.  The C-H bonds of fats are much less
polar.

 > does it
 > attract more to dye and detergent then fat????

Sorry, I don't understand what you are asking here.  Detergents seek out the
interface between water and fat globules.  Different dyes range from being
may be more soluble in water to being more soluble in oil.  Is that what you
are asking?

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois
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