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Acids & Bases

Acids & Bases. They are everywhere.. In your food In your house EVEN IN YOU!!!!!. What is an acid?. An acid is a solution that has an excess of H+ ions. It comes from the Latin word acidus that means "sharp" or "sour". The more H + ions, the more acidic the solution.

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Acids & Bases

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  1. Acids & Bases They are everywhere.. In your food In your house EVEN IN YOU!!!!!

  2. What is an acid? • An acid is a solution that has an excess of H+ ions. It comes from the Latin word acidus that means "sharp" or "sour". • The more H + ions, the more acidic the solution.

  3. Properties of an Acid • Tastes Sour • Conduct Electricity • Corrosive, which means they break down certain substances. Many acids can corrode fabric, skin, and paper • Some acids react strongly with metals • Turns blue litmus paper red • React with bases to form water and salt. Picture from BBC Revision Bites http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/acids_bases_1.shtml

  4. Acids Affect Indicators, by changing their color Blue litmus paper turns red in contact with an acid (and red paper stays red).

  5. Acids have a pH lessthan 7

  6. Uses of Acids • Acetic Acid = Vinegar • Citric Acid = lemons, limes, & oranges. It is in many sour candies such as lemonhead & sour patch. • Ascorbic acid = Vitamin C which your body needs to function. • Sulfuric acid is used in the production of fertilizers, steel, paints, and plastics. • Car batteries

  7. Effects of Acid Rain on Marble(marble is calcium carbonate) George Washington: BEFORE acid rain George Washington: AFTER acid rain

  8. Acids Neutralize Bases HCl + NaOH→NaCl + H2O -Neutralization reactions ALWAYS produce a salt and water. -Of course, it takes the right proportion of acid and base to produce a neutral salt.

  9. Sulfuric Acid = H2SO4 • Highest volume production of any chemical in the U.S. (approximately 60 billion pounds/year) • Used in the production of paper • Used in production of fertilizers • Used in petroleum refining; auto batteries

  10. Nitric Acid = HNO3 • Used in the production of fertilizers • Used in the production of explosives • Nitric acid is a volatile acid – its reactive components evaporate easily • Stains proteins yellow (including skin!)

  11. Hydrochloric Acid = HCl • Used in the “pickling” of steel • Used to purify magnesium from sea water • Part of gastric juice, it aids in the digestion of proteins • Sold commercially as Muriatic acid

  12. Phosphoric Acid = H3PO4 • A flavoring agent in sodas (adds “tart”) • Used in the manufacture of detergents • Used in the manufacture of fertilizers • Not a common laboratory reagent

  13. Acetic Acid = HC2H3O2 (also called Ethanoic Acid, CH3COOH) • Used in the manufacture of plastics • Used in making pharmaceuticals (drugs) • Acetic acid is the acid that is present in household vinegar

  14. Coffee is a weak acid!

  15. What is a base? • A base is a solution that has an excess of OH- ions. • Another word for base is alkali. • Bases are substances that can accept hydrogen ions

  16. Properties of a Base • Feel Slippery • Taste Bitter • Corrosive • Can conduct electricity. (Think alkaline batteries.) • Do not react with metals. • Turns red litmus paper blue.

  17. Bases have a pH greaterthan 7

  18. Bases Neutralize Acids Milk of Magnesia contains magnesium hydroxide, Mg(OH)2, which neutralizes stomach acid, HCl. 2 HCl + Mg(OH)2 Magnesium salts can cause diarrhea (thus they are used as a laxative) and may also cause kidney stones. MgCl2 + 2 H2O

  19. Uses of Bases • Bases give soaps, ammonia, and many other cleaning products some of their useful properties. • The OH- ions interact strongly with certain substances, such as dirt and grease. • Chalk and oven cleaner are examples of familiar products that contain bases. • Your blood is a basic solution.

  20. pH Scale • pHis a measure of how acidic or basic a solution is. • The pH scale ranges from 0 to 14. • Acidic solutions have pH values below 7 • A solution with a pH of 0 is very acidic. • A solution with a pH of 7 is neutral. • Pure water has a pH of 7. • Basic solutions have pH values above 7.

  21. pH Scale • A change of 1 pH unit represents a tenfold change in the acidity of the solution. • For example, if one solution has a pH of 1 and a second solution has a pH of 2, the first solution is not twice as acidic as the second—it is ten times more acidic.

  22. “DO NOW” FOR THURSDAY! • Scientifically speaking, how are acids and bases similar and how are they different?

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