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Acids, Bases, and Salts

Acids, Bases, and Salts. Chapter 8. Students Will Be Able To:. Compare and contrast acids and bases and identify the characteristics they have. List some common examples of acids and bases . Describe the ionization of strong acids in water and the dissociation of strong bases in water. Acids.

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Acids, Bases, and Salts

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  1. Acids, Bases, and Salts Chapter 8

  2. Students Will Be Able To: • Compare and contrast acids and bases and identify the characteristics they have. • List some common examples of acids and bases. • Describe the ionization of strong acids in water and the dissociation of strong bases in water.

  3. Acids • Is any compound that increases the number of hydronium ions (H3O+) when dissolved in water • Includes citric fruits (limes, lemons), dill pickles, apples, and grapes • When acids dissolve in water, they ionize • Process of forming ions • Those that ionize are able to conduct electricity

  4. Acids • Acids get their sour taste from hydronium ions • Can be identified using an indicator • An indicator is a compound that changes color depending on the pH of a solution or substance • Blue litmus paper turns red in the presence of an acid

  5. Strong vs. Weak Acids • Strong acids ionize completely while weak acids do not • Strong acids conduct electricity good while weak acids do not • Strong acids are good electrolytes because they have as many H3O+ as they possibly can • Electrolytes are substances that dissolves in water and are capable of conducting electric current

  6. Examples of Strong and Weak Acids • Some examples of strong acids • Hydrochloric acid, HCl • present in your stomach • Sulfuric acid, H2SO4 • car batteries; the most-used industrial chemical • Nitric acid, HNO3 • used in manufacturing fertilizers and explosives • Some examples of weak acids • Acetic acid, CH3COOH • the acid in vinegar • Formic acid, HCOOH • the acid in stinging ants • Citric acid, H3C6H5O7 • the acid in citrus fruits

  7. Use of Acids • Acids are used in many manufacturing processes • They are also needed by living organisms • Care should be taken when using either weak or strong acids

  8. Bases • Is any compound that increases the number of hydroxide ions (OH-) when dissolved in water • Have a bitter, soapy taste • Basic solutions tend to feel slippery • Also contain ions and are capable of conducting electricity • Are identified using red litmus paper • Turns blue in the presence of a base

  9. Strong vs. Weak Bases • Strong bases contain a metal ion and a hydroxide ion that ionizes completely in water • Also known as metal hydroxides • Are able to conduct electricity well • Therefore, strong bases are good electrolytes • Strong bases often are not soluble in water

  10. Strong vs. Weak Bases • Weak bases do not ionize completely in water to form hydroxide ions

  11. Care with Bases • Bases in their concentrated form are more dangerous than acids • Make sure care is taken when working with bases

  12. Students Will Be Able To: • Describe how to name acids. • Write formulas for acids.

  13. Naming Acids • Naming acids depend on whether or not the acid contains oxygen in the anion • All acids have the same cation (hydrogen) so there is no need to name it

  14. Naming Acids Without Oxygen • The acid name comes from the root name of the anion name • The prefix hydro- and the suffix -ic are then added to the root name of the anion • Examples: • HCl, which contains the anion chloride, is called hydrochloric acid • HCN, which contains the anion cyanide, is called hydrocyanic acid

  15. Naming Acids With Oxygen • Suffixes are used based on the ending of the original name of the oxyanion. • If the name of the polyatomic anion ended with -ate, change it to -ic for the acid and if it ended with -ite, change it to -ous in the acid • Examples: • HNO3, which contains the polyatomic ion nitrate, is called nitric acid • HNO2, which contains the polyatomic ion nitrite, is called nitrous acid

  16. Writing Formulas • Convert the name to a formula • Determine the anion and add an “H” per negative charge • Assume that hydrogen, H, has a +1 charge in the compound, even though acids are usually made of non-metals, and therefore covalent • For example • sulfur-ic acid contains a sulfate ion • 2 H+  +  SO42-  = H2SO4

  17. Students Will Be Able To: • Determine the meaning of pH. • Examine the relationship between pH and acid or base strength. • Identify a neutralization reaction. • Describe the importance of titrations while working with acids and bases. • Determine what a salt is and how it forms. • Compare and contrast soaps and detergents.

  18. pH • Is a value used to express the acidity of alkalinity of a solution • Corresponds to the concentration of hydronium and hydroxide ions

  19. pH Scale • Ranges from 0 to 14 • Acids • 0 to 7 (strong 0-3; weak 4-7) • Bases • 7-14 (strong 11-14; weak 7-10) • Neutral • 7

  20. Differences in Acidity • Small differences in pH mean larger differences in the hydronium ion concentration

  21. Determining pH • pH can be determined using several indicators that change color at different pH values • pH can also be measured using a pH meter • Measures the amount of electric current being created by the movement of the ions in the solution

  22. Acid- Base Reactions • A reaction between an acid and a base is known as a neutralization reaction • Neutralization is an ionic reaction

  23. Acid- Base Reactions • Neutralization reactions tend to form salts and water • Not all neutralization reactions produce neutral solutions • Depends on • Amount of acids and bases that are combined • Whether the acids and bases are weak or strong

  24. Titrations • It is a neutralization reaction in which the known concentration of one solution is used to determine the unknown concentration of another solution

  25. Salts • Salt can be almost any combination of cations and anions • Common table salt contains sodium chloride, NaCl, which is a salt that is formed from the reaction of hydrochloric acid with sodium hydroxide • Salts are useful substances, and are all around us • Examples • sodium hydrogen carbonate, baking soda • silver bromide and silver iodide, in photographic film • barium sulfate, sometimes used in taking X rays • calcium carbonate, in chalk, limestone, and marble

  26. Soaps • Works with water to clean objects • Are able to dissolve in oil and water • Are made by reacting animal fats or vegetable oils with a solution of sodium hydroxide or potassium hydroxide

  27. Detergents • Are used instead of soap to wash clothes and dishes • Soap does not work well with hard water- leaves behind soap scum • Are made of sodium, potassium, or ammonia salts with fatty acids

  28. Bleach and Disinfectants • A disinfectant is a substance that kills bacteria and viruses • Bleach is an example of a disinfectant • It is a basic solution

  29. Antacids • Are weak bases that neutralize stomach acid

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