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					                         What is soap?
If oil is added to water, the two liquids do not mix.

Because of this, grease stains can be difficult to remove
during washing.

Soaps are compounds                           soap molecule
which act as emulsifiers.

This means that they                                        water
help the oil to mix
with the water.



                                            oil
How do soaps work?
                   How are soaps made?
Soaps are usually made from vegetable fats and oils.
These consist of 3 fatty acid chains, held together by a
glycerol molecule.




The reaction used to make soap from fats and oils is
called saponification.
How are soaps made?
                        What are soapless detergents?
Soapless detergents can be made from crude oil, rather than
vegetable oils or animal fats.
Soapless detergents are still made of long, hydrophobic
carbon chains, but the hydrophilic end of the molecule is a
sulfonate:




sodium octadecylsulfonate



    hydrophobic end interacts            hydrophilic end interacts
        with oil molecules                with water molecules
               Soaps vs. soapless detergents
What are the advantages and disadvantages of soapless
detergents over soaps?
 Soaps form a scum with hard water, meaning that it is
  more difficult to produce a lather. Soapless detergents
  react with the substances in hard water to form soluble
  compounds, and so do not form a scum.

 Soapless detergents can be made from the by-products
  of the oil refining process, so can be cheaper to produce
  than soaps.

 Some soapless detergents are not biodegradable.
  This means that they stay in the water system causing
  froth in rivers and streams.
     Biological and non-biological
Biological detergents
are soapless
              detergents
detergents that
contain enzymes.

The enzymes
are used to break
down chemicals,
e.g. in stains on
clothes.

Non-biological detergents do not contain enzymes, but just
rely on the action of the detergent to remove grease and
stains from items.
Advantage or disadvantage?

				
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