Acids and Bases in the Home Chapter 6.4 Acids and Bases in the Home

SOAP Dissolves in both grease and water. Soaps are emulsifiers Emulsion is a mixture of things that normally don’t mix. You need an emulsifer to help!

Soap The nonpolar side of a soap molecule is “attached” (attracted to) nonpolar grease and oil, the polar side hangs on to the water, and the dirt slips off your hands and is pulled down the drain, trapped, along with the water molecules, by that pesky soap molecule!

What you don’t need to know about soap.... Lots of detail in top paragraph on pg 208, about the chemical reaction involved in making soap. Don’t worry about it. Just know that one end of the molecule is nonpolar and dissolves the grease or oil, and the other end is polar, and dissolves in water.

Detergents Soap doesn’t work well in “hard water” Hard water = water with lots of dissolved ions like Mg, Ca, and Fe Soap + hard water = soap SCUM!!!!

Soaps vs Detergent – both have one polar and one nonpolar “end”, but... (soap has COO- or carboxylate group) derived from animal fat detergent has SO3- group, known as sulfonate group derived from petroleum

Ammonia solution NH3 + H2O  NH4 + OH solution of ammonia gas, water, ammonium ions, hydroxide ions. hydroxide ions mix with grease forms an emulsion. NH3 + H2O  NH4 + OH 

Disinfectants kill bacteria. Bleach is a disinfectant. Bleach also removes color from clothing. http://www.clorox.com/science/rmp/how.html

Antacids weak bases to neutralize excess stomach acid.

Shampoos pH balanced usually between 5 and 8

Acids and Bases in the Kitchen Lemon juice keeps apples from oxidizing. Oxidation is what causes the apple to turn brown after you cut it (when it is exposed to oxygen in the air)

Making yogurt Remember when we added vinegar (acidic) to milk and it curdled? Similar process in making yogurt, when bacteria convert lactose (milk sugar) to lactic acid.