Transcript Modern Chemistry Chapter 14 - Licking Heights School District

Modern Chemistry
Chapter 14
Acids & Bases
Section 1
Properties of Acids & Bases
• Aqueous solutions of acids taste sour.
• Acids change the color of acid-base
indicators.
• Some acids react with active metals and
release hydrogen gas.
• Acids react with bases to produce salts
and water.
• Acids conduct electricity (electrolytes).
Common acids
• Name some items
with a sour taste, and
it is usually an acid or
has an acid as an
ingredient.
Binary Acids
• A binary acid is an
acid that contains
only hydrogen and
one of the more
electronegative
elements. (group 17
elements primarily)
Binary Acid Nomenclature
• Naming binary acids:
– The name of a binary acid begins with the prefix
“hydro”.
– The root of the name of the second element follows
this prefix.
– The name then ends with the suffix “ic”.
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HF = hydrofluoric acid
HCl = hydrochloric acid
HBr = hydrobromic acid
HI = hydroiodic acid
H2S = hydrosulfuric acid
Acid Nomenclature Practice
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Write the formula for the following binary acids
1) hydrochloric acid
2) hydroiodic acid
Name the following binary acids:
1) HBr(aq)
2) H2S(aq)
3) HF(aq)
Oxyacids & Nomenclature
• An oxyacid is an acid that is a compound of hydrogen,
oxygen, and a third element, usually a nonmetal.
• Nomenclature of an oxyacid.
– Determine the name of the polyatomic ion combined
with the hydrogen.
– If the name of the ion ends with “ate”, replace it with
“ic” and add the word acid.
– If the name of the ion ends with “ite”, replace it with
“ous” and add the word acid.
• For example for HNO3, NO31- = nitrate, so the name of the acid is
nitric acid.
• Also for HNO2, NO21- = nitrite, so the name of the acid is nitrous
acid.
Acid Nomenclature Practice
• Name the following oxyacids:
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H2SO4 (aq)
H2SO3 (aq)
HClO (aq)
HClO2 (aq)
HClO3 (aq)
HClO4 (aq)
HC2H3O2 (aq)
Acid Nomenclature Practice
• Write the formula for the following acids:
• phosphoric acid
• phosphorous acid
• nitrous acid
• nitric acid
Common Industrial Acids
• Sulfuric acid (H2SO4) is the most commonly
produced industrial chemical and is used in
petroleum refining, metallurgy, and is used in the
production of fertilizer, metals, paint, dye, paper
& detergents. It is also used in car batteries.
Common Industrial Acids
• Nitric acid (HNO3) stains proteins (like those in
your skin) yellow. It is used in the manufacture
of explosives, plastics, and pharmaceuticals.
Common Industrial Acids
• Phosphoric acid (H3PO4) is used primarily in
the manufacture of fertilizers and animal feed. It
is also used as a flavoring for beverages.
Common Industrial Acids
• Hydrochloric acid (HCl) is the acid produced
by the stomach for digestion. It is also called
muriatic acid and is used to clean masonry and
maintain the acidity of swimming pools.
Common Industrial Acids
• Acetic acid (HC2H3O2) is the active ingredient in
vinegar and is produced by the fermentation of
certain plants. It is used as a flavoring agent, a
preservative, and as a fungicide. It is also used
in the manufacture of plastics.
Properties of Bases
• Aqueous solutions of bases taste bitter.
• Dilute aqueous solutions of bases feel
slippery.
• Bases change the color of acid-base
indicators.
• Bases react with acids to produce salts &
water.
• Bases conduct electricity (electrolytes).
Base Nomenclature
• All bases contain the hydroxide (OH) ion.
• Most bases also contain a metallic ion.
• The number of hydroxide ions is
determined by the charge of the metal ion.
• Na+ + OH-  NaOH
• Ca2+ + OH-  Ca(OH)2
• Al3+ + OH-  Al(OH)3
Base Nomenclature
• Naming bases is VERY difficult.
– Name the cation.
– Add “hydroxide”.
Ba(OH)2 = barium hydroxide
NH4OH = ammonium hydroxide
KOH = potassium hydroxide
Arrhenius Acids & Bases
• An Arrhenius acid is a chemical
compound that increases the
concentration of hydrogen, H+ (hydronium,
H3O+) ions in an aqueous solution.
• An Arrhenius base is a chemical
compound that increases the
concentration of hydroxide (OH-) ions in an
aqueous solution.
Acid & Base Strength
• A strong acid is one that ionizes completely in an
aqueous solution.
• A weak acid is an acid that releases few hydrogen ions
in an aqueous solution.
• A strong base, like a strong acid, is one that completely
dissociates to produce hydroxide ions in an aqueous
solution and acts as a strong electrolyte.
• A weak base is a weak electrolyte that produces few
hydroxide ions and is usually not very soluble in water.
– Do section review questions #1 through 5 on page 476.
Cross-Disciplinary Connection
• Read the Cross-Disciplinary Connection
entitled “Acid Water-A Hidden Menace” on
page 477.
• Answer the three questions at the end of
the article.
Section 2
Acid-Base Theories
• Bronsted-Lowry acid is a molecule or ion that is a
proton (H+) donor.
• Bronsted-Lowry base is a molecule or ion that is a
proton acceptor.
• A monoprotic acid can donate only one proton (H+) per
molecule.
• A polyprotic acid can donate more than one proton per
molecule.
– diprotic acid can donate 2 protons, such as H2SO4
– triprotic acid can donate 3 protons, such as H3PO4
Lewis Acids & Bases
• A Lewis acid is an electron pair acceptor.
• A Lewis base is an electron pair donor.
Section 3
Acid-Base Reactions
• A conjugate base is the species that remains
after a Bronsted-Lowry acid gives up a proton.
• A conjugate acid is the species that is formed
when a Bronsted-Lowry base gains a proton.
– For the reaction
HF + H2O  F- + H3O+
– the F- is the conjugate base and the H3O+ is the
conjugate acid.
Neutralization Reaction
• A neutralization reaction is the reaction between an
acid and a base to produce a salt and water.
HCl + NaOH  NaCl + H2O
• neutralization is the reaction of a hydronium (H3O+) and
a hydroxide (OH-) ion to form a water molecule.
H3O+ + OH-  2 H2O
• A salt is an ionic compound composed of a cation from a
base and an anion from an acid.
Na+ + Cl-  NaCl
Acid Rain
• Gaseous byproducts of industrial
processes enter the atmosphere and
combine with water to produce an acid
that the falls as acid rain.
SO2 + H2O  H2SO3
SO3 + H2O  H2SO4
NO + H2O  HNO2
NO2 + H2O  HNO3
Modern Chemistry Chapter 14
Test Review
• 35 multiple choice questions
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properties of acids and bases (9)
definition, naming & identification of binary and oxyacids (5)
determining formulas of oxyacids from their names (3)
names and uses of the common industrial acids; sulfuric, nitric,
hydrochloric, phosphoric, and acetic (6)
definitions and identification of Arrhenius acids & bases (3)
definitions of weak & strong acids (1)
identify diprotic & triprotic acids (2)
definition of Bronsted-Lowry acids & bases (2)
definition of Lewis acids & bases (2)
definition of conjugate acids & bases (2)