1. History of Cleaning Many years ago and even today in the third world, clothes are cleaned by beating on rocks in a river or stream. Wood ashes contain potassium and sodium carbonate, which form alkaline solutions in water with some detergent properties. Sodium carbonate is still sold today as washing soda.

2. Chapter 172 Soap Production Made from lye, NaOH, and fats –Produces fatty acids –Historically, left unreacted NaOH behind Soap is salt of long-chain fatty acid Modern soapmaking removes leftover NaOH –Addition of perfumes, dyes, oils, and creams

3. Chapter 173 The saponification of a triglyceride.

4. Chapter 174 How Soap Works Hydrophobic end: nonpolar –Dissolves nonpolar material Hydrophilic end: polar –Dissolves in water

5. Chapter 175 A typical soap molecule.

6. Chapter 176 Water, grease, and soap.

7. Chapter 177 Grease micelles with embedded soap molecules.

8. Chapter 178 The Cleansing Action of Soap 12.8

9. Chapter 179 Soaps (cont.)

10. Chapter 1710 Soap forms rich suds in soft water.

11. Chapter 1711 Problems with Soap Does not work in hard water –Contains calcium, magnesium, and iron ions –Bind to hydrophilic end –Leave soap scum Soap cannot work with stains –Fewer suds form

12. Problems with Soap Water that contains calcium, magnesium, and iron ions is called hard water. These ions will react with and precipitate soap, reducing its effectiveness.

13. Chapter 1713 Brighteners Absorb invisible ultraviolet light and reemit it as visible light

14. Chapter 1714 Synthesis of Nylon