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Chapter 14
Acids and Bases
14-03-01a
Title
 Spacefilling model of hydrochloric acid
Caption
 Hydrogen is present as an H+ ion.
Notes
 HCl is a very common acid, used to clean metals, prepare and process some foods, and refine metal ores. Some might know this as muriatic acid.
Keywords
 acid, hydrochloric acid
14-03-02b
Title
 Spacefilling model of sulfuric acid
Caption
 Hydrogen is present as an H+ ion.
Notes
 H2SO4 is a very common acid, used in laboratories and in the manufacture of fertilizers, explosives, dyes, and glue. It is also used in automobile batteries.
Keywords
 acid, sulfuric acid
14-03-03c
Title
 Spacefilling model of nitric acid
Caption
 Hydrogen is present as an H+ ion.
Notes
 HNO3 is a very common acid, used in laboratories and in the manufacture of fertilizers, explosives, dyes, and glue.
Keywords
 acid, nitric acid
14-03-04d
Title
 Spacefilling model of acetic acid
Caption
 Hydrogen is present as an H+ ion.
Notes
 HC2H3O2 is a very common acid, found in vinegar. It is a carboxylic acid, possessing the characteristic -COOH group. It is derived from organic sources.
Keywords
 acid, acetic acid, carboxylic acid, organic
14-03-06f
Title
 Spacefilling model of carboxylic acid group
Caption
 Hydrogen is present as an H+ ion.
Notes
 The -COOH group is present in all carboxylic acids. Carboxylic acids are derived from organic sources.
Keywords
 acid, carboxylic acid, organic
14-03-07g
Title
 Spacefilling models of citric acid and malic acid
Caption
 Hydrogen is present as an H+ ion. Note that not all of the hydrogens in these molecules are present as ions: Most are bonded to carbon atoms through ordinary covalent bonds.
Notes
 Citric acid and malic acid are common acids, found in fruits: citric acid in citrus fruits, and malic acid in apples, grapes, and wine.
Keywords
 acid, citric acid, malic acid, carboxylic acid, organic
14-05
Title
 HCl is a strong electrolyte
Caption
 The Arrhenius definition of an acid is a substance that produces H+ ions in solution. We will see later that these H+ ions associate with H2O to form H3O+ ions.
Notes
 The HCl molecule dissociates in water to produce the H+ and Cl- ions. The H+ ions associate with H2O to form H3O+ ions. HCl is a strong acid, because the acid is 100% dissociated in water.
Keywords
 acid, hydrochloric acid, hydronium, strong electrolyte, Arrhenius
14-05-01un
Title
 Lewis dot structures for hydronium ion formation
Caption
 The H+ ions associate with H2O to form H3O+ ions. HCl is a strong acid, because the acid is 100% dissociated in water.
Notes
 The Arrhenius definition of an acid is a substance that produces H+ ions in solution. The H+ ions are so small they are readily attracted to a lone pair on water. The resulting polyatomic ion, called a hydronium ion, satisfies oxygen's octet and the duets of all three hydrogens.
Keywords
 acid, hydrochloric acid, hydronium, water, hydrogen ion
14-06
Title
 NaOH is a strong electrolyte
Caption
 The Arrhenius definition of a base is a substance that produces OH- ions in solution.
Notes
 The NaOH molecule dissociates in water to produce the Na+ and OH- ions. NaOH is a strong base, because the base is 100% dissociated in water.
Keywords
 base, sodium hydroxide, strong electrolyte, Arrhenius
14-07
Title
 Conjugate acidÐbase pairs
Caption
 A conjugate acidÐbase pair is any two substances related to each other by the transfer of a proton.
Notes
 According to the Br¿nsted-Lowry definition, the acid is the proton donor; the base is the proton acceptor. In these examples, H2O and NH4+ would be the acids; NH3 and OH- would be the bases.
Keywords
 Br¿nsted-Lowry, proton, acid, base, conjugate acidÐbase pair
14-07-01un
Title
 Conjugate acidÐbase pair equation
Caption
 A conjugate acidÐbase pair is any two substances related to each other by the transfer of a proton. Here, water transfers a proton to an ammonia molecule.
Notes
 According to the Br¿nsted-Lowry definition, the acid is the proton donor; the base is the proton acceptor.
Keywords
 Br¿nsted-Lowry, proton, acid, base, conjugate acidÐbase pair
14-07-02un
Title
 Conjugate acidÐbase pair equation: Example 14.1a
Caption
 A conjugate acidÐbase pair is any two substances related to each other by the transfer of a proton. Here, sulfuric acid transfers a proton to a water molecule.
Notes
 According to the Br¿nsted-Lowry definition, the acid is the proton donor; the base is the proton acceptor.
Keywords
 Br¿nsted-Lowry, proton, acid, base, conjugate acidÐbase pair
14-07-03un
Title
 Conjugate acidÐbase pair equation: Example 14.1b
Caption
 A conjugate acidÐbase pair is any two substances related to each other by the transfer of a proton. Here, water transfers a proton to a bicarbonate ion.
Notes
 According to the Br¿nsted-Lowry definition, the acid is the proton donor; the base is the proton acceptor.
Keywords
 Br¿nsted-Lowry, proton, acid, base, conjugate acidÐbase pair
14-07-04un
Title
 General pattern for acidÐbase neutralization
Caption
 An acidÐbase neutralization generally follows the pattern shown. This is one of the most important acidÐbase reactions.
Notes
 The net ionic equation is: H+ + OH- --> H2O
Keywords
 proton, acid, base, salt, water, neutralization
14-07-10un
Title
 Multistep solution map for converting mL of an NaOH solution to grams HCl
Caption
 The stated factors use a metric conversion, the given molarity of the NaOH solution, and the balanced reaction equation to make the conversion. The 1:1 factor arises from the balanced equation.
Notes
 The factors can be adapted to any similar mL-grams conversion.
Keywords
 mole, chemical formula, molarity, balanced equation, neutralization, acid, base
14-07-11un
Title
 Solution map for calculating molarity
Caption
 The stated factor uses the moles of HCl and volume of the HCl solution in liters.
Notes
 This factor can be adapted to any molarity determination.
Keywords
 mole, molarity, acid
14-07-12un
Title
 Dissociation of a strong acid
Caption
 When a strong acid dissociates, 100% of the molecules give up the H+ ion. The single arrow in the reaction equation indicates that 100% dissociation occurs.
Notes
 The single arrow indicates complete ionization of the acid.
Keywords
 acid, ionization, dissociation, hydrochloric acid, hydronium ion
14-08
Title
 HCl in water undergoes complete ionization
Caption
 When HCl dissolves in water, it completely ionizes into H3O+ and Cl-. The solution contains no intact HCl. HCl is therefore a strong electrolyte.
Notes
 The H+ ions join with water molecules to form hydronium ions.
Keywords
 acid, ionization, dissociation, hydrochloric acid, hydronium ion, strong electrolyte
14-09-01un
Title
 Dissociation of a weak acid
Caption
 When a weak acid dissociates, less than 100% of the molecules give up the H+ ion. The double arrow in the reaction equation indicates that incomplete dissociation occurs.
Notes
 The double arrow indicates incomplete ionization of the acid. One way of looking at it is to imagine acid molecules ionizing at the same time that ions are reconstituting themselves into undissociated acid molecules. The result is that the solution will never have all acid molecules dissociated.
Keywords
 acid, ionization, dissociation, hydrofluoric acid, hydronium ion
14-10
Title
 HF in water undergoes incomplete ionization
Caption
 When HF dissolves in water, only a fraction of the dissolved molecules ionize into H3O+ and F- ions. The solution contains many intact HF molecules.
Notes
 The H+ ions join with water molecules to form hydronium ions.
Keywords
 acid, ionization, dissociation, hydrofluoric acid, hydronium ion, weak electrolyte
14-12
Title
 Strong and weak acids
Caption
 a) In a strong acid, the attraction between H+ and A- is low, resulting in complete ionization. b) In a weak acid, the attraction between H+ and A- is high, resulting in partial ionization.
Notes
 Another interpretation states that the strong acid is a primarily ionic compound, but the weak acid has significant covalent character.
Keywords
 acid, ionization, dissociation, weak electrolyte, strong electrolyte
14-13
Title
 NaOH in water undergoes complete ionization
Caption
 When NaOH dissolves in water, it completely dissociates into Na+ and OH-. The solution contains no intact NaOH. Would NaOH be a strong or weak electrolyte?
Notes
 When NaOH dissolves in water, it completely ionizes into Na+ and OH-. The solution contains no intact NaOH. NaOH is therefore a strong electrolyte.
Keywords
 base, ionization, dissociation, sodium hydroxide, strong electrolyte
14-14
Title
 Ammonia in water undergoes incomplete ionization
Caption
 When NH3 dissolves in water, it partially ionizes to form NH4+ and OH-. However, only a fraction of the molecules ionize. Most NH3 molecules remain as NH3. Would NH3 be a strong or weak electrolyte?
Notes
 When NH3 dissolves in water, only a fraction of the dissolved molecules ionize with water to form NH4+ and OH-. The solution contains many intact NH3 molecules. Ammonia is a weak electrolyte.
Keywords
 base, ionization, dissociation, ammonia, hydroxide ion, ammonium ion, weak electrolyte
14-14-01un
Title
 Water acts as both an acid and a base
Caption
 Water can accept protons from an acid to form hydronium ion. But water can also provide protons to a base to form hydroxide ions. When only water is present, water acts as both an acid and a base, in a process called self-ionization: H2O + H2O --> H3O+ + OH-
Notes
 Water is a very weak acid and a very weak base. Whether water acts as an acid or base depends on what other species is present.
Keywords
 acid, base, amphoteric, water, self-ionization
14-14-02un
Title
 Water is amphoteric
Caption
 Water can accept protons from an acid to form hydronium ion. But water can also provide protons to a base to form hydroxide ions. When only water is present, water acts as both an acid and a base, in a process called self-ionization: H2O + H2O --> H3O+ + OH-
Notes
 Water is a very weak acid and a very weak base. Whether water acts as an acid or base depends on what other species is present.
Keywords
 acid, base, amphoteric, water, self-ionization
14-14-03un
Title
 Logarithms and significant figures
Caption
 Only the numbers to the right of the decimal place are significant in a logarithm. This makes sense, because a logarithm expresses the power of 10 that corresponds to a measurement.
Notes
 In this example, the measurement 1.0 x 10-3 has two significant figures. Therefore, the logarithm should be expressed to two places to the right of the decimal.
Keywords
 pH, logarithm, significant figures
14-14-04un
Title
 Logarithms and significant figures
Caption
 Only the numbers to the right of the decimal place are significant in a logarithm. This makes sense, because a logarithm expresses the power of 10 that corresponds to a measurement.
Notes
 In this example, the measurement 1.00 x 10-3 has three significant figures. Therefore, the logarithm should be expressed to three places to the right of the decimal.
Keywords
 pH, logarithm, significant figures
14-14-05o
Title
 pH scale
Caption
 The pH is a unit defined to express the acidity of solutions. The more acidic the substance, the lower its pH.
Notes
 pH was defined in order to express very widely ranging hydronium ion concentrations in a scale that we can easily understand.
Keywords
 pH, logarithm, molarity
14-15
Title
 The pH scale as a logarithmic scale
Caption
 The pH scale is a logarithmic scale. A decrease of 1 unit on the pH scale corresponds to an increase of 10 in H3O+ concentration. How much of an increase in H3O+ concentration corresponds to a decrease of 2 pH units?
Notes
 Each pH unit corresponds to a power of ten in the hydronium ion concentration. Therefore, a decrease of two pH units would be a 100-fold increase in hydronium ion concentration.
Keywords
 pH, logarithm, molarity
14-17
Title
 Buffer systems
Caption
 A buffer contains significant amounts of a weak acid and its conjugate base. The acid consumes any added base, and the base consumes any added acid. In this way, a buffer resists pH change.
Notes
 Buffers are found in blood and other biological systems, in which a narrow, constant pH range is necessary for proper function.
Keywords
 buffer, acid, base, conjugate base, weak acid, neutralization, pH
14-18
Title
 Map of pH of precipitation in the U.S.
Caption
 Average pH of precipitation in the United States for the period 12/25/2000 to 1/1/2001. Low pH values can correspond to environmental damage.
Notes
 The map contains values from the National Atmospheric Deposition Program.
Keywords
 acid, base, neutralization, pH, acid rain, environment
14-20
Title
 1980Ð1997 SO2 emissions from utilities
Caption
 1980 to 1997 SO2 emissions from utilities. The height of each bar represents annual SO2 emissions for that region in the year noted. Under the Clean Air Act and its amendments, SO2 emissions are decreasing in most parts of the country.
Notes
 SO2 contributes to acid rain because it is readily converted to sulfuric acid in the atmosphere.
Keywords
 sulfur dioxide, sulfuric acid, acid rain, Clean Air Act
14-20-01un
Title
 Multistep solution map for converting mL H2SO4 to moles NaOH
Caption
 The stated factors use a metric conversion, the given molarity of the H2SO4 solution, and the balanced reaction equation to make the conversion. The 2:1 factor arises from the balanced equation.
Notes
 The factors can be adapted to any similar mL-moles conversion.
Keywords
 mole, chemical formula, molarity, balanced equation, neutralization, acid, base
14-20-02p
Title
 HF is a weak acid
Caption
 When HF dissolves in water, only a fraction of the dissolved molecules ionize into H3O+ and F-. The solution contains many intact HF molecules.
Notes
 The H+ ions join with water molecules to form hydronium ions.
Keywords
 acid, ionization, dissociation, hydrofluoric acid, hydronium ion, weak electrolyte
14-20-03q
Title
 HI is a strong acid
Caption
 When HI dissolves in water, it completely ionizes into H3O+ and I-. The solution contains no intact HI. HI is therefore a strong electrolyte.
Notes
 The H+ ions join with water molecules to form hydronium ions.
Keywords
 acid, ionization, dissociation, hydroiodic acid, hydronium ion, strong electrolyte
14-20-04r
Title
 HCHO2 is a weak acid
Caption
 When HCHO2 dissolves in water, only a fraction of the dissolved molecules ionize into H3O+ and CHO2-. The solution contains many intact HCHO2 molecules.
Notes
 The H+ ions join with water molecules to form hydronium ions.
Keywords
 acid, ionization, dissociation, oxalic acid, hydronium ion, weak electrolyte
14-20-05s
Title
 HNO3 is a strong acid
Caption
 When HNO3 dissolves in water, it completely ionizes into H3O+ and NO3-. The solution contains no intact HNO3. HNO3 is therefore a strong electrolyte.
Notes
 The H+ ions join with water molecules to form hydronium ions.
Keywords
 acid, ionization, dissociation, nitric acid, hydronium ion, strong electrolyte
14-20-07un
Title
 Solution map for calculating molarity
Caption
 The stated factor uses the moles of NaOH and volume of the NaOH solution in liters.
Notes
 This factor can be adapted to any molarity determination.
Keywords
 mole, molarity, base
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