Chapter 5 chemical 4 consumers


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Chapter 5 chemical 4 consumers

  2. 2. Chemical is very important to human beings’ life Almost everything that we use, we eat, we drink everyday are related closely to chemistry
  3. 3. For examples: - The soap we use to bath -The detergent we use to clean the dirt -The food additives to make food tasted better -The medicines tocure disease
  4. 4. 5.1 Soap & Detergent
  5. 5. Who discovers the soap? And when its history started?
  6. 6. Since water is essential for life, the earliest people lived near water and knew something about its cleansing properties - at least that it rinsed mud off their hands.
  7. 7. A soap-like material found in clay cylinders during the excavation of ancient Babylon is evidence that soapmaking was known as early as 2800 B.C.
  8. 8. At about the same time, Moses gave the Israelites detailed laws governing personal cleanliness. He also related cleanliness to health and religious purification.
  9. 9. <ul><li>The early Greeks bathed for aesthetic reasons and apparently did not use soap. Instead, they cleaned their bodies with blocks of clay, sand, pumice and ashes, then anointed themselves with oil, and scraped off the oil and dirt with a metal instrument. Clothes were washed without soap in streams. </li></ul>
  10. 10. Soap making was an established craft in Europe by the seventh century. Vegetable and animal oils were used with ashes of plants, along with fragrance.
  11. 11. Commercial soapmaking in the American colonies began in 1608 AD
  12. 12. Large-scale commercial soapmaking occurred in 1791 when a French chemist, Nicholas Leblanc , patented a process for making soda ash, or sodium carbonate. Soda ash is the alkali obtained from ashes that combines with fat to form soap.
  13. 13. 20 years later, Michel Eugene Chevreul , another French chemist, discovered that the chemical nature and relationship of fats, glycerine and fatty acids.
  14. 14. Also important to the advancement of soap technology was the mid-1800s invention by the Belgian chemist, Ernest Solvay , of the ammonia process, which also used common table salt, or sodium chloride, to make soda ash. Solvay's process further reduced the cost of obtaining this alkali , and increased both the quality and quantity of the soda ash available for manufacturing soap.
  15. 15. What forms SOAP? <ul><li>sodium (Na) @ potassium (K) salts of </li></ul><ul><li>long- chain fatty acid </li></ul>Fats/Oil
  16. 16. The structure of soap <ul><li>the ionic head group is water-soluble , the nonpolar tail insoluble </li></ul>Tail Tail Head
  17. 17. hydropho b ic hydrophi l ic The structure of soap
  18. 18. The structure of soap
  19. 19. Tail How SOAP & water can clean so much than water ?
  20. 20. Cleansing Action <ul><li>Hidrophilic </li></ul><ul><li>part (head) </li></ul><ul><li>attracted </li></ul><ul><li>to water </li></ul>Water molecules
  21. 21. Cleansing Action Dirt (grease) Hidrophobic part (tail) likes to dissolved in grease
  22. 22. Cleansing Action <ul><li>The droplets </li></ul><ul><li>do not coagulate </li></ul><ul><li>because of </li></ul><ul><li>repulsion between </li></ul><ul><li>negative charges </li></ul><ul><li>on surface </li></ul><ul><li>Scrubbing clothes </li></ul><ul><li>helps to break the </li></ul><ul><li>grease into small </li></ul><ul><li>droplets </li></ul>
  23. 23. Cleansing Action <ul><li>The droplets </li></ul><ul><li>suspended in water </li></ul><ul><li>& form emulsion </li></ul><ul><li>Rinsing process </li></ul><ul><li>could wash away </li></ul><ul><li>these droplets & </li></ul><ul><li>leaves surface clean </li></ul>
  24. 24. Cleansing Action
  25. 25. Cleansing Action
  26. 26. Detergent <ul><li>Soaps are made up of natural resources </li></ul><ul><li>But detergents are made up of synthetic resources such as petroleum fractions </li></ul>
  27. 27. Structure of Detergent Tail Head
  28. 28. Cleansing Action <ul><li>Cleansing action of detergent is just the same with soaps </li></ul>
  29. 33. Soap Detergent Advantage <ul><li>Biodegradable </li></ul><ul><li>Do not cause any pollution </li></ul><ul><li>effective in both of soft & hard water </li></ul><ul><li>do not form scum in hard water (Mg 2+ , Ca 2+ ) </li></ul><ul><li>Do not form precipitate in acidic water </li></ul>Disadvantage <ul><li>form scum in hard water, cleansing action not effective </li></ul><ul><li>Form precipitate in acidic water </li></ul><ul><li>Non-biodegradable </li></ul><ul><li>harm aquatic lives </li></ul>