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Unit 9 Notes

Unit 9 Notes. Acids, Bases, and Salts. Acids. An acid is a su bstance that produces Hydrogen ion H + or hydronium H 3 O + in solution. Properties of Acids. 1. taste sour 2. electrolytes – conduct electricity because of ions

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Unit 9 Notes

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  1. Unit 9 Notes Acids, Bases, and Salts

  2. Acids • An acid is a substance that produces Hydrogen ion H+ or hydronium H3O+ in solution

  3. Properties of Acids • 1. taste sour • 2. electrolytes – conduct electricity because of ions • 3. corrosive – eat away at metals as metallic compounds and hydrogen gas is produced

  4. Different Acids

  5. The most widely usedchemical in the world is sulfuric acid. It can cause severe burns because it is a dehydrating agent. This means that it takes all of the water out of materials, including skin.

  6. STRONG ACIDS • A Strong Acid completely ionizes (breaks apart) in water and releases a lot of H+. • Example: sulfuric acid (battery acid)

  7. Weak Acids • A Weak acid only partially beaks down in water, so it doesn’t release much H+. • Example: acetic acid (vinegar)

  8. Bases • A BASE is a substance that produces hydroxide ions OH- in solution. AKA=Alkine

  9. Properties of Bases • 1. feel slippery • 2.taste bitter • 3. electrolytes • 4. corrosive

  10. Most bases contain a metal and OH- (hydroxide) • The exception is ammonia, NH3, but it still produces OH- when mixed with water • NH3 + H2O NH4+ + OH-

  11. Strong Bases • A strong base completely dissociates (breaks apart) in solution and releases lots of OH-. • Example: sodium hydroxide

  12. Weak Base • A weak base does not completely break apart in solution and does not release as much OH- • Example: Aluminum hydroxide

  13. pH Scale • pH is the measure of H3O+ in a solution • pH is used to measure the strength of acids and bases. It ranges from 0 to 14. • Substances with a pH lower than 7 are acidic • Substances with a pH higher than 7 are basic • Substances with a pH of 7 are neutral

  14. Indicators • Substances that change color in the presence of acids and bases • Examples: • 1. bromythymol blue turns yellow for acid and blue for base • 2. phenylthalein turns clear for acid and pink for base

  15. pH Scale Strong Acids Weak Acids Neutral (pure water) Weak Bases Strong Bases

  16. Neutralization • If you want to NEUTRALIZE an acid or base, you add a BUFFER.

  17. Buffers • Buffers are ACIDS, BASES, or SALTS that are mixed with acids or bases to make their pH closer to 7. • If you want to neutralize an acid, your buffer must be a BASE • If you want to neutralize a base, your buffer must be an ACID • Buffers in your body help keep your blood’s pH at 7.4. This is necessary because most of your food contains ACIDS

  18. Titration • Process that can be used to determine the concentration of an acid or base

  19. Neutralization is a chemical reaction between an acid and a base • H+ from the acid combine with OH- from the base to form water • Metals from the base combine with nonmetals from the acid to form a salt • Example: HCl + NaOH NaCL + H2O

  20. Salts • Most SALTS are formed with a METAL and a NONMETAL other than OXYGEN. • Some salts are formed with a METAL and a POLYATOMIC ION.

  21. Acid Rain • Unpolluted rain typically has a pH value of 5.6 which is acidic, but not harmful • Any rain that is below 5.6 is considered acid rain • Acid Rain Can: • Dissolve marble in buildings and statues • Corrode metal (buildings, cars) • Kill plankton (then fish die)

  22. Ways Acid Rain can Occur • Burning coal releases sulfur – sulfur combines with water in the air – sulfuric acid forms • Car exhaust releases nitrogen oxide – combines with water – nitric acid forms

  23. Ways to Prevent Acid Rain • “scrubbers on smokestacks” • Nuclear power • Cleaner fuel

  24. Soaps • Soaps are organic salts, this means that they contain carbon. • Soaps are made by reacting fats or oils with sodium hydroxide or potassium hydroxide. • Soaps made with NaOH are solids • Soaps made with KOH are liquids • Glycerin is another product of this reaction which is used in lotion

  25. The process of making soap is called SAPONIFICATION

  26. Detergents • Detergents are similar to soaps, but fo not form soap scum which is a precipitate that forms when soap is used in hard water (lots of minerals) • This is why most laundry products are detergents, not soaps

  27. Esters • An ESTER is an organic compound formed by the reaction of an organic acid with an alcohol • Esters are responsible for the odors and flavors of flowers, fruits, and other foods. Esters are added to jello and candy to give the flavors of strawberry, banana, or apple. • Organic acids are also used to make polyester fibers

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