Chemistry 19.1

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Chemistry 19.1
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Acid-Base Theories
19.1

• Bracken Cave, near San Antonio, Texas, is home to
  twenty to forty million bats. Visitors to the
  cave must protect themselves from the dangerous
  levels of ammonia in the cave. Ammonia is a
  byproduct of the bats urine. You will learn why
  ammonia is considered a base.

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Properties of Acids and Bases
19.1

• Properties of Acids and Bases
• What are the properties of acids and bases?

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Properties of Acids and Bases
19.1

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

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Properties of Acids and Bases
19.1

• Citrus fruits contain citric acid. Tea contains
  tannic acid.

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Properties of Acids and Bases
19.1

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

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Properties of Acids and Bases
19.1

• Antacids use bases to neutralize excess stomach
  acid. The base calcium hydroxide is a component
  of mortar.

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Arrhenius Acids and Bases
19.1

• Arrhenius Acids and Bases
• How did Arrhenius define an acid and a base?

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Arrhenius Acids and Bases
19.1

• 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.

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Arrhenius Acids and Bases
19.1

• Hydrochloric Acid

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Arrhenius Acids and Bases
19.1

• Arrhenius Acids
• Acids that contain one ionizable hydrogen, such
  as nitric acid (HNO3), are called monoprotic
  acids.
• Acids that contain two ionizable hydrogens, such
  as sulfuric acid (H2SO4), are called diprotic
  acids.
• Acids that contain three ionizable hydrogens,
  such as phosphoric acid (H3PO4) are called
  triprotic acids.

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Arrhenius Acids and Bases
19.1
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Arrhenius Acids and Bases
19.1

• Arrhenius Bases
• Hydroxide ions are one of the products of the
  dissolution of an alkali metal in water.

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Arrhenius Acids and Bases
19.1
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Arrhenius Acids and Bases
19.1

• Milk of magnesia is a base used as an antacid.

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Brønsted-Lowry Acids and Bases
19.1

• Brønsted-Lowry Acids and Bases
• What distinguishes an acid from a base in the
  Brønsted-Lowry theory?

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Brønsted-Lowry Acids and Bases
19.1

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

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Brønsted-Lowry Acids and Bases
19.1

• Why Ammonia is a Base

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Brønsted-Lowry Acids and Bases
19.1

• Conjugate Acids and Bases
• A conjugate acid is the particle formed when a
  base gains a hydrogen ion.
• A conjugate base is the particle that remains
  when an acid has donated a hydrogen ion.

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Brønsted-Lowry Acids and Bases
19.1

• A conjugate acid-base pair consists of two
  substances related by the loss or gain of a
  single hydrogen ion.
• A substance that can act as both an acid and a
  base is said to be amphoteric.

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Brønsted-Lowry Acids and Bases
19.1
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Brønsted-Lowry Acids and Bases
19.1

• A water molecule that gains a hydrogen ion
  becomes a positively charged hydronium ion (H3O).

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Lewis Acids and Bases
19.1

• Lewis Acids and Bases
• How did Lewis define an acid and a base?

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Lewis Acids and Bases
19.1

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

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Lewis Acids and Bases
19.1

• A Lewis acid is a substance that can accept a
  pair of electrons to form a covalent bond.
• A Lewis base is a substance that can donate a
  pair of electrons to form a covalent bond.

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Lewis Acids and Bases

• Animation 25
• Compare the three important definitions of acids
  and bases.

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Lewis Acids and Bases
19.1
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for Conceptual Problem 19.1

• Problem Solving 19.1
• Solve Problem 1 with the help of an interactive
  guided tutorial.

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19.1 Section Quiz.

• 19.1.

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19.1 Section Quiz.

• 1. Which of the following is NOT a
  characteristic of acids?
• taste sour
• are electrolytes
• feel slippery
• affect the color of indicators

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19.1 Section Quiz.

• 2. Which compound is most likely to act as an
  Arrhenius acid?
• H2O
• NH3.
• NaOH.
• H2SO4.

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19.1 Section Quiz.

• 3. A Lewis acid is any substance that can accept
  
• a hydronium ion.
• a proton.
• hydrogen.
• a pair of electrons.

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END OF SHOW