Polarity of Solvents

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Polarity of Solvents
Background Information for Soap Lab
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A Hydrocarbon

• Typical petroleum product
• Non-polar

Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 470
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Oil and Water Dont Mix

• Oil is nonpolar
• Water is polar
• Like dissolves like

Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 470
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Hydrogenation
H2
Timberlake, Chemistry 7th Edition, page 570
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Molecular Polarity
nonpolar molecules -- e are shared
equally -- tend to be symmetric
e.g., fats and oils
polar molecules -- e NOT shared
equally e.g., water
Like dissolves like. polar polar
solution nonpolar nonpolar solution polar
nonpolar suspension (wont mix evenly)
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Using Solubility Principles
Chemicals used by body obey solubility principles.
-- water-soluble vitamins e.g., vit. C
-- fat-soluble vitamins e.g., vits. A, D
Dry cleaning employs nonpolar liquids.
-- polar liquids damage wool, silk
-- also, dry clean for stubborn stains (ink,
rust, grease) -- tetrachloroethylene is in common
use
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emulsifying agent (emulsifier)
-- molecules w/both a polar AND a nonpolar end
-- allows polar and nonpolar substances to mix
detergent
lecithin
eggs
e.g., soap
MODEL OF A SOAP MOLECULE
Na1
NONPOLAR HYDROCARBON TAIL
POLAR HEAD
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Soap Making
Borax (Na2B4O7 _10H2O), the most widespread
borate mineral was found to help remove dirt from
people and cloth. Borax is crumbly and powdery,
and dissolves easily in water. Borax became an
alternative to the very harsh soap which was used
prior to the discovery of borax in the late
1800's. This light and easy to use substance was
hailed the world over as a washing, cleansing,
antiseptic, preservative, and medicine miracle.
In the 1880s, large borate deposits were
discovered in Death Valley, California. However,
the Death Valley borate deposits were located
almost 170 miles from the nearest railway. In
order to get the borate to the railway
economically, the owners of the Death Valley
mines used large wagons pulled by teams of 20
mules. The detergents made from this borate were
thus sold as "20 Mule Team Borax". 
                                                  
                                      A 20 mule
team hauling borax in Death Valley
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Soap Article
Soap Article
ChemMatters Feb. 1985 Questions
Soap Article
ChemMatters Feb. 1985 Questions
The Story on Suds
(8 min 19 sec)
Keys
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Saponification
3 sodium palmitate (soap)
Glycerol
Glyceryl tripalmitate (tripalmitin)
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A Phospholipid
Timberlake, Chemistry 7th Edition, page 576
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Stearic Acid
Fatty acid
Carboxylic acid group
Kelter, Carr, Scott, Chemistry A Wolrd of Choices
1999, page 257
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Cleaning Action of Soap
Micelle
Timberlake, Chemistry 7th Edition, page 573
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SOAP vs. DETERGENT --
made from animal and -- made from petroleum
vegetable fats -- works better in hard water
Hard water contains minerals w/ions like Ca2,
Mg2, and Fe3 that replace Na1 at polar end of
soap molecule. Soap is changed into an
insoluble precipitate (i.e., soap scum).
micelle a liquid droplet covered
w/soap or detergent molecules
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Solvation
Like Dissolves Like
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Solvation

• Soap / Detergent
• polar head with long nonpolar tail
• dissolves nonpolar grease in polar water

micelle
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Lab - Soap Making
Lab  SOAP making 
Lab  SOAP making 
Keys
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A Model of a Cell Membrane
Timberlake, Chemistry 7th Edition, page 587
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Formation of a Triglyceride
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Lava Lamp
It is
a philosophy
once ruled our world
an art form
progressive
post-modern
here to stay
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Lava Lamp
It is
a philosophy
Polar mixture
Water
the primordial ooze
Polyethylene glycol
once ruled our world
the moment
Nonolar mixture
an art form
Chlorinated paraffin
Paraffin from kerosene
a classic
Heat transfer coil
progressive
prehistoric
Bulb gives heat and light
post-modern
here to stay