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Chapter 15. Acids and Bases. 15.1: What are Acids and Bases?. Objectives: To name acids and bases. To write formulas for acids and bases. Rules for Naming Acids. -ide hydro_____ic acid -ate _____ic acid -ite _____ous acid *If a compound begins with hydrogen name it as an acid.
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Chapter 15 Acids and Bases
15.1: What are Acids and Bases? • Objectives: • To name acids and bases. • To write formulas for acids and bases.
Rules for Naming Acids -ide hydro_____ic acid -ate _____ic acid -ite _____ous acid *If a compound begins with hydrogen name it as an acid.
Examples: Naming Acids 1. HCl • The anion is chloride (Cl-) • For an anion ending in –ide hydro___ic acid • Therefore, the name is hydrochloric acid
Examples: Naming Acids 1. HCl • The anion is chloride (Cl-) • For an anion ending in –ide hydro___ic acid • Therefore, the name is hydrochloric acid 2. HNO3 • The anion is nitrate (NO3-) • For an anion ending in –ate ___ic acid • Therefore, the name is nitric acid
Examples: Naming Acids 1. HCl • The anion is chloride (Cl-) • For an anion ending in –ide hydro___ic acid • Therefore, the name is hydrochloric acid 2. H2SO4 • The anion is sulfate (SO42-) • For an anion ending in –ate ___ic acid • Therefore, the name is sulfuric acid 3. H2SO3 • The anion sulfite (SO32-) • For an anion ending in –ite ___ous acid • Therefore, the name acid sulfurous acid
Name the following compound: HBr • Bromic acid • Bromous acid • Hydrobromic acid • Hydrobromous acid • None of the above
Name the following compound: HBr • Bromic acid • Bromous acid • Hydrobromic acid • Hydrobromous acid • None of the above
Name the following compound: H2C2O4 • Chromic acid • Oxalate acid • Dihydrogen dicarbon tetraoxide • Oxalic acid • None of the above
Name the following compound: H2C2O4 • Chromic acid • Oxalate acid • Dihydrogen dicarbon tetraoxide • Oxalic acid • None of the above
Practice: Naming Acids 1. H2SO3 2. HF 3. H3PO4 4. HNO3 5. HI
Practice: Naming Acids 1. H2SO3 : sulfurous acid 2. HF : hyrofluoric acid 3. H3PO4 : phosphoric acid 4. HNO3 : nitric acid 5. HI : hydroiodic acid
Examples: Writing Formulas for Acids H+ SO42- 1. Sulfuric acid • The anion is sulfate (SO42-) • The cation is H+ • Criss-cross charges to get H2SO4 2. Carbonic acid • The anion is carbonate (CO32-) • The cation is H+ • Criss-cross charges to get H2CO3 H2SO4 H+ CO32- H2CO3
Practice: Writing Formulas for Acids 1. Hydrochloric acid 2. Nitric acid 3. Phosphorous acid 4. Hydroiodic acid
Practice: Writing Formulas for Acids 1. Hydrochloric acid: HCl 2. Nitric acid: HNO3 3. Phosphorous acid: H3PO3 4. Hydroiodic acid: HI
15.1: What are acids and bases? continued • Objectives: • To list properties of acids and bases. • To define acid and base. • To identify the acid, base, conjugate acid, and conjugate base in a chemical reaction.
Properties of Acids • Taste sour • Form Hydronium Ions (H3O+) • Conduct electricity • React with metals
Properties of Bases • Taste bitter • Feel slippery • Generate Hydroxide Ions (OH-)
Acid • Arrhenius Acid: any substance that, when added to water, increases the hydronium ion (H3O+) concentration *Note: H+ and H3O+ are used interchangeably
Base • Arrhenius Base: generates hydroxide ions (OH-) when dissolved in water
BrØnsted-LowRY Acid • A substance that donates a proton (H+) to another substance.
BrØwnsted-lowry base • A substance that accepts a proton (H+).
Conjugate Acid and Conjugate Base • Conjugate Acid: an acid that forms when the base gains a H+ • Conjugate Base: the base that forms when an acid loses an H+
Identify the acid, base, conjugate acid, and conjugate base in the following chemical reactions: • HCl + OH- Cl- + H2O acid base c. base c. acid 2. HNO3 + OH- NO3- + H2O 3. H2O + HCO3- H2CO3 + OH-
Identify the acid, base, conjugate acid, and conjugate base in the following chemical reactions: • HCl + OH- Cl- + H2O acid base c. base c. acid 2. HNO3 + OH- NO3- + H2O acid base c. base c. acid 3. H2O + HCO3- H2CO3 + OH- acid base c. acid c. base
Amphoteric Substances • An amphoteric substance can donate AND accept protons. • Example: HCO3- is amphoteric HCO3- + NH3 CO32- + NH4+ Acid Base C. Base C. Acid HCO3- + H3O+ H2CO3 + H2O Base Acid C. Acid C. Base
15.2 Acidity, Basicity, and pH • Objective: • To calculate the concentration of the hydronium ion and the hydroxide ion.
Self-Ionization of Water H2O(l) + H2O(l) H3O+(aq) + OH-(aq) [H3O+] = [OH-] = 1.00 x 10-7 M What is the Keq for water?
Self-Ionization of Water H2O(l) + H2O(l) H3O+(aq) + OH-(aq) [H3O+] = [OH-] = 1.00 x 10-7 M What is the Keq for water? Keq = [H3O+][OH-] = (1.00 x 10-7)(1.00 x 10-7) Keq = 1.00 x 10-14 = Kw
Summary Kw = [H3O+][OH-] Kw = 1.00 x 10-14
Determining [H3O+] and [OH-] using Kw • Step 1: Write the Kw expression. • Step 2: Determine concentrations. • Step 3: Solve!
Example • What is [OH-] in a 3.00 x 10-5 M solution of HCl? Kw = [H3O+][OH-] 1 x 10-14 = (3.00 x 10-5) [OH-] [OH-] = 3.33 x 10-10 M
Practice • Calculate the hydronium ion concentration in an aqueous solution of KOH that has a hydroxide ion concentration of 7.24 x 10-4 M.
Practice • Calculate the hydronium ion concentration in an aqueous solution of KOH that has a hydroxide ion concentration of 7.24 x 10-4 M. • What is the [OH-] in a 0.450 M solution of HNO3?
Practice 3. What is [H3O+] in a solution of NaOH whose concentration is 3.75 x 10-2 M?
Practice 3. What is [H3O+] in a solution of NaOH whose concentration is 3.75 x 10-2 M? 4. Calculate the hydroxide ion concentration of a 0.200 M solution of HClO4.
15.2: Acidity, Basicity, and pH continued • Objective: • To calculate pH.
pH • pH: A value used to represent acidity or alkalinity (basicity) of a solution.
Measuring pH • Indicators: dyes that turn different colors in solutions of different pH • Examples: litmus paper, bromothymol blue, methyl orange, phenolphthalein
Calculating pH pH = -log[H3O+]
Example • What is the pH of a solution with a 0.05 M hydronium ion concentration? pH = -log[H3O+] pH = -log(0.05) pH = 1.30 *Note: pH does not have units.
Practice • What is the pH of 0.00010 M solution of nitric acid?
Practice • What is the pH of 0.00010 M solution of nitric acid? • Calculate the pH if [H3O+] = 5.0 x 10-3 M.