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Acids, Bases, & Salts. Acid:. A substance that produces hydrogen ions, H+, in solution. Ion. (negatively or positively) charged atom. Base:. A substance that produces hydroxide ions, OH-, in solution. Indicator:. An organic compound that changes color in an acid or base.
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Acid: A substance that produces hydrogen ions, H+, in solution.
Ion (negatively or positively) charged atom
Base: A substance that produces hydroxide ions, OH-, in solution.
Indicator: An organic compound that changes color in an acid or base. Litmus paper: red in acid blue in base
Properties of Acids: • Acids taste sour (never taste!!) • Acids are electrolytes (contain ions) • Acids are corrosive • Acids react with indicators to cause a predictable color change.
Properties of Bases: • In undissolved state most bases are crystalline solids • In solution most bases: • feel slippery (never touch) • taste bitter (never taste) • bases are also corrosive, and can cause severe burns
pH A measure of the concentration of hydronium ions.
0 - 6 = acidic (the lower the value the more acidic)8 - 14 = basic (the higher the value the more basic)
Neutralization: A chemical reaction between an acid and a base. Forms water and a salt Neutralization reactions
Example: HNO3 + KOH--> H2O(l)+ K+ + NO3- Water Salt
Neutralization Reaction Video • http://www.marymount.k12.ny.us/marynet/stwbwk03/03hchem/emreaction/emreaction.html
Salt: A salt is a compound formed when the negative ions from an acid combine with the positive ions from a base.
pH & Digestion: Mouth • The 1st place food goes is mouth. • Saliva contains amylase. • Amylase helps to break down food. • Saliva is near pH 7 (best pH for amylase to work.
pH & Digestion: Stomach • Stomach is lined with enzymes & hydrochloric acid (HCl). • Enzymes work to break down food into macromolecules the body can use. • pH is about 2. (These enzymes work best at this pH.)
pH & Digestion: Small Intestine • Digestion is completed mostly in small intestine. • Important molecules pass into bloodstream from here. • pH is about 8 (these enzymes work best at this pH.)