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Bond Polarity

Use electronegativity values to determine bond type

Atoms Practice
Practice Bond Polarity
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Clean Clarity

How is soap able to clean?

Credit: Keith Williamson
Source: http://www.flickr.com/photos/elwillo/5172558180/sizes/m/in/photolist-8T5HkA-8T2va2-eavEgc-8jAu8F-7LGrTe-7LLoXY-by4isW-9QqWdB-8BNEry-9p4kdW-eYDPq6-eYRcdN-eYDPnK-eYRcpC-eYRcjw-eYRcJJ-eYRd81-eYRcdb-eYDPPF-eYRd3d-eYRcGq-eYRcB3-eYRd3y-eYDNKz-eYDPJc-eYDPjP-7BXfFV-eYDNX2-eYRc23-8MHZnc-bLrE7M-8vsKMV-8ru6Pu-9zXUQt-9zXUSK-eYRcgs-eYRcMh-eYRd5U-eYDPHz-eYDPQ2-eYDNZK-eYRbQu-eJ3ZMh/
License: CC BY-NC 3.0


Soap has a special structure that allows it to grip on to dirt and be washed away by water.  The Hydrophobic, nonpolar tail is attracted to the grime because it is a triglyceride.  The head is an alkali and attracted to water because it is hydrophilic.  You can see a colorful demonstration of this when you mix soap with milk and food coloring.  The soap is attracted to the fat in the milk and this causes the food coloring to disperse.

Creative Applications

  1. If you replaced the milk with water, what would happen?
  2. If you changed the percent fat, what would happen?
  3. Why do cleanup crews pour detergent into the ocean after an oil spill?
    Watch the video in the resources to answer the next questions:  
  4. Why do soaps and detergents try to reduce the water surface tension?
  5. Which end of the soap molecule is attracted to grime and why? 



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