Section 2Acids, Bases, and Salts

Section 2: Reactions of Acids with Bases

Preview• Key Ideas• Bellringer• Acid-Base Reaction• Neutralization Reaction• Titration• Graphing Skills• Salts

Section 2Acids, Bases, and Salts

Key Ideas

〉What is a neutralization reaction?

〉To a chemist, what exactly is a salt?

Section 2Acids, Bases, and Salts

BellringerYou have learned that acids and bases form ions in solution. The characteristic ions are the hydronium, or H3O+, ion for acids and the hydroxide, or OH–, ion for bases. Below are several reactions between acids and bases.From what you know about reactions, acids, and bases, predict what the products of the following reactions will be.1. HCl + NaOH ______ + H2O2. HCl + KOH KCl + ______3. HNO3 + KOH ______ + ______4. H2SO4 + Ca(OH)2 ______ + ______5. HBr + AgOH ______ + ______6. HClO4 + NaOH ______ + ______7. 2HNO3 + Ba(OH)2 ______ + ______8. H2SO4 + 2NH4OH ______ + ______

Section 2Acids, Bases, and Salts

SPS6d Compare and contrast the components and properties of acids and bases.

Section 2Acids, Bases, and Salts

EQ: What are the components, properties

and some common examples of acids and

bases?

Section 2Acids, Bases, and Salts

Acid-Base Reactions

〉What is a neutralization reaction?

Section 2Acids, Bases, and Salts

9-2-1 Acid-Base Reactions

A neutralization reaction is the reaction between an acid and a base.

Section 2Acids, Bases, and Salts

9-2-2 Acid-Base Reactions

• neutralization reaction: the reaction of the ions that characterize acids and the ions that characterize bases to form water molecules and a salt

Section 2Acids, Bases, and Salts

9-2-4 Acid-Base Reactions, continued

•A strong acid ionizes completely in solution.HCl + H2O Cl– + H3O+

Section 2Acids, Bases, and Salts

9-2-5 Acid-Base Reactions, continued

•A strong base ionizes completely in solution.NaOH Na+ + OH–

Section 2Acids, Bases, and Salts

9-2-6 Acid-Base Reactions, continued

•The total neutralization reaction is the following:Cl– + H3O+ + Na+ + OH– Na+ + Cl– + 2H2O

Section 2Acids, Bases, and Salts

9-2-7 Acid-Base Reactions, continued

• salt: an ionic compound that forms when a metal atom or a positive radical replaces the hydrogen of an acid

Section 2Acids, Bases, and Salts

9-2-8 Acid-Base Reactions, continued

• Neutralization reactions form water and a salt.

Section 2Acids, Bases, and Salts

9-2-9 Acid-Base Reactions, continued

• Neutral solutions are not always formed.

Section 2Acids, Bases, and Salts

9-2-10 Acid-Base Reactions, continued

The final pH of the solution depends onthe amounts and strengths of acid and base that are combined.

Section 2Acids, Bases, and Salts

Neutralization Reaction

Section 2Acids, Bases, and Salts

Salts

〉To a chemist, what exactly is a salt?

Section 2Acids, Bases, and Salts

9-2-11 Salts

〉To a chemist, a salt can be almost any combination of cations and anions, except hydroxides and oxides, which are bases.

Section 2Acids, Bases, and Salts

9-2-12 Salts

• Salts have many uses.

Section 2Acids, Bases, and Salts

9-2-13 Salts

• Salts are important in the body.

Section 2Acids, Bases, and Salts

9-2-14 Salts, continuedSome Common Salts

Section 2Acids, Bases, and Salts

Acid-Base Reactions, continued• Titrations are used to determine concentration.

• titration: the process of adding carefully measured amounts of one solution to another solution

• equivalence point: the point when the original amount of acid equals the original amount of base added

– strong acid with a strong base, equivalence point = pH 7

– strong acid with a weak base, equivalence point < pH 7

– strong base with a weak acid, equivalence point > pH 7

Section 2Acids, Bases, and Salts

Titration

Section 2Acids, Bases, and Salts

Graphing SkillsInterpreting Titration CurvesHydrochloric acid, HCl, was titrated with potassium hydroxide, KOH. How many moles of KOH were added to reach the equivalence point?

Section 2Acids, Bases, and Salts

Graphing Skills, continued

1. Locate the equivalence point on the graph.A strong acid was titrated with a strong base. The y-axis indicates the pH, so the equivalence point on the titration curve has a y-value of 7.

2. Read the moles of KOH from the graph.The x-axis indicates how many moles of KOH were added. At pH = 7, 0.4 mol of KOH was added.