Soaps:

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Soaps

• Cleaning up!

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The Function of Soaps

• Soaps clean things
• Oil-based dirt
• Water-based dirt
• This means that soap has a dual nature!
• Oil and water dont mix, but soap overcomes this

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Making Soap Saponification

• 1. Sodium Hydroxide (NaOH)
• Strong base, corrosive
• Lye, Drano
• Very soluble (dissociates completely)
• Forms ions Na and (OH)-
• Releases heat when it dissolves
• Tastes bitter

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Making Soap

• 2. Fat (Lard)
• Adds consistency to the soap
• Made of chains of carbon atoms (its a molecule)
• Glyceryl stearate CH3(CH2)16COOH

H - C C C C C C C C C C C C
C C C C C O C H
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Making Soap

• 3. Water
• Aids in the mixing of other ingredients

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Making Soap

• Reaction
• Fat Sodium Hydroxide ?
• Sodium Stearate (Soap) Methanol
• Sodium Stearate CH3(CH2)16COO-Na
• The charges play a role in how soap works

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The Chemistry of Soaps Solubility

• Solubility The ability of one substance to
  dissolve in another
• Form a solution (solute and solvent)
• General rule LIKE DISSOLVES LIKE
• Oil-based substances dissolve in other oil-based
  substances
• Water-based substances dissolve in other
  water-based substances
• Examples Latex paint vs. oil-based paint
  cleanups
• Salad dressing

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The Role of Polarity

• Polar A substance with oppositely charged ends
• Ionic Compounds NaCl- , Na(OH)-, water
• Nonpolar A substance with no difference in
  charge

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Classifying the Parts of Soap

• Soap cleans both oil and water-based dirt
• Dual Nature
• The oily part from the fatty acid (chain of
  carbons)
• No charge (Nonpolar)
• Hydrophobic (Water hating) attracted to oils
• The watery part from the NaOH
• Charged (Polar)
• Hydrophilic (Water loving) attracted to polar
  (charged) dirt

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How Soap Cleans

• Cleaning dirt
• Soap surrounds the dirt
• Polar part on the outside (closest to water)
• Nonpolar part closest to the dirt
• Like dissolves like

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Detergents

• Similar to soaps
• Long hydrocarbon chain
• Different from soaps
• Instead of -COOH on the end, these have sulfonic
  acid or phosphoric acid group
• Work well in hard water or cold water
• May cause environmental damage

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A Soap Timeline

• 1950s Automatic dishwasher powders Liquid
  laundry, hand dishwashing and all-purpose
  cleaning products Fabric softeners (rinse-cycle
  added) Detergent with oxygen bleach 1960s
  Prewash soil and stain removers Laundry powders
  with enzymes Enzyme presoaks 1970s Liquid
  hand soaps Fabric softeners (sheets and
  wash-cycle added) Multifunctional products
  (e.g., detergent with fabric softener) 1980s
  Detergents for cooler water washing Automatic
  dishwasher liquids Concentrated laundry powders
  1990s Ultra (superconcentrated) powder and
  liquid detergents Ultra fabric softeners
  Automatic dishwasher gels Laundry and cleaning
  product refills