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Chemistry Chapter 19

Chemistry Chapter 19.

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Chemistry Chapter 19

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  1. Chemistry Chapter 19

  2. Figure 19.1 Many items contain acids or bases, or produce acids and bases when dissolved in water. a. Citrus fruit contain citric acid. b. Tea contains tannic acid. c. Antacids use bases to neutralize excess stomach acid. d. The base calcium hydroxide is a component of mortar.

  3. Acids taste sour, will change the color of an acid-base indicator, and can be strong or weak electrolytes in aqueous solution.

  4. Bases taste bitter, feel slippery, will change the color of an acid-base indicator, and can be strong or weak electrolytes in aqueous solution.

  5. Arrhenius said that acids are hydrogen-containing compounds that ionize to yield hydrogen ions (H+) in aqueous solution. He also said that bases are compounds that ionize to yield hydroxide ions (OH−) in aqueous solution.

  6. monoprotic acids. • any acid that contains one ionizable proton (hydrogen ion); nitric acid (HNO3) is a monoprotic acid

  7. diprotic acids. • any acid that contains two ionizable protons (hydrogen ions); sulfuric acid (H2SO4) is a diprotic acid

  8. triprotic acids. • any acid that contains three ionizable protons (hydrogen ions); phosphoric acid (H3PO4) is a triprotic acid

  9. The Brønsted-Lowry theory defines an acid as a hydrogen-ion donor, and a base as a hydrogen-ion acceptor.

  10. Why Ammonia is a Base

  11. In this reaction, ammonia is the hydrogen-ion acceptor and therefore is a Brønsted-Lowry base. Water, the hydrogen-ion donor, is a Brønsted-Lowry acid. Hydrogen ions are transferred from water to ammonia

  12. conjugate acid • the particle formed when a base gains a hydrogen ion; NH4+ is the conjugate acid of the base NH3

  13. conjugate base • the particle that remains when an acid has donated a hydrogen ion; OH- is the conjugate base of the acid water

  14. conjugate acid-base pair • two substances that are related by the loss or gain of a single hydrogen ion; ammonia (NH3) and the ammonium ion (NH4+) are a conjugate acid-base p

  15. amphoteric. • a substance that can act as both an acid and a base

  16. ). Lewis proposed that an acid accepts a pair of electrons during a reaction, while a base donates a pair of electrons.

  17. Lewis acid • any substance that can accept a pair of electrons to form a covalent bond

  18. Lewis base • any substance that can donate a pair of electrons to form a covalent bond

  19. (3) Key Concept What are the properties of acids and bases? Hint • (4) Key Concept How did Arrhenius define an acid and a base?Hint • (5) Key Concept How are acids and bases defined by the Brønsted-Lowry theory?Hint • (6) Key Concept What is the Lewis theory of acids and bases?Hint

  20. (7) • What is a conjugate acid-base pair?Hint • Write equations for the ionization of HNO3 in water and the reaction of CO32− with water. For each equation, identify the hydrogen-ion donor and hydrogen-ion acceptor. Then label the conjugate acid-base pairs in each equation.

  21. )Identify the following acids as monoprotic, di-protic, or triprotic. Explain your reasoning. • H2CO3 • H3PO4 • HCl • H2SO4

  22. hydronium ion (H3O+). • the positive ion formed when a water molecule gains a hydrogen ion

  23. Hydrogen Ions from Water self-ionization a term describing the reaction in which two water molecules react to produce ions

  24. In water or aqueous solution, hydrogen ions (H+) are always joined to water molecules as hydronium ions (H3O+). Hydrogen ions in aqueous solution have several names. Some chemists call them protons. Others prefer to call them hydrogen ions or hydronium ions. In this textbook, either H+ or H3O+ is used to represent hydrogen ions in aqueous solution.

  25. The self-ionization of water occurs to a very small extent. In pure water at 25°C, the equilibrium concentration of hydrogen ions ([H+]) and the equilibrium concentration of hydroxide ions ([OH−]) are each only 1 × 10−7M. This means that the concentrations of H+ and OH− are equal in pure water.

  26. neutral solution. • an aqueous solution in which the concentrations of hydrogen and hydroxide ions are equal; it has a pH of 7.0

  27. Ion Product Constant for Water

  28. For aqueous solutions, the product of the hydrogen-ion concentration and the hydroxide-ion concentration equals 1.0 × 10−14. • [H+] × [OH−] = 1.0 × 10−14

  29. ion-product constant for water (Kw). • the product of the concentrations of hydrogen ions and hydroxide ions in water; it is 1 X 10-14 at 25°C

  30. acidic solution • any solution in which the hydrogen-ion concentration is greater than the hydroxide-ion concentration

  31. basic solution • any solution in which the hydroxide-ion concentration is greater than the hydrogen-ion concentration

  32. alkaline solutions. • a basic solution

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