Chapter 6
More on Chemical
Compounds
Chapter
Map
Monatomic Ion Names
• Monatomic Cations
– (name of metal)
• Groups 1, 2, and 3 metals
• Al3+, Zn2+, Cd2+, Ag+
– (name of metal)(Roman numeral)
• All metallic cations not mentioned above
• Monatomic Anions
– (root of nonmetal name)ide
Roots of Nonmetals
H hydrC carbN nitrP phosphO oxS sulfSe selen-
F fluorCl chlorBr bromI iod-
Monatomic Anions
H−
Hydride
Nitride N3−
Phosphide P3−
Oxide O2−
Sulfide S2−
selenide Se2−
fluoride F−
chloride Cl−
bromide Br−
iodide I−
Polyatomic Ions
Ion
Name
Ion
Name
NH4+
ammonium
NO3−
nitrate
OH−
hydroxide
SO42−
sulfate
CO32−
carbonate
C2H3O2−
acetate
PO43−
phosphate
Polyatomic Ions
with Hydrogen
•
•
•
•
•
HCO3−
HSO4−
HS−
HPO42−
H2PO4−
hydrogen carbonate
hydrogen sulfate
hydrogen sulfide
hydrogen phosphate
dihydrogen phosphate
Recognizing Ionic
Compounds
• Metal-nonmetal…binary ionic
compound
• Metal-polyatomic ion
• Ammonium-nonmetal or
ammonium polyatomic ion
Converting Ionic
Formulas to Names
• Name
– (name of cation) (name of anion)
Cation Names
name of metal
Metals with one
possible charge (Al,
Zn, Cd, and Groups 1,
2, 3)
Metals with more than name(Roman numeral)
one possible charge
(the rest)
polyatomic cations
(e.g. ammonium)
name of polyatomic ion
Anion Names
monatomic anion
(root of nonmetal name)ide
polyatomic anion
name of polyatomic ion
Converting Ionic
Names to Formulas
• Determine the formula, including
charge, for the cation and anion.
• Determine the ratio of the ions
that yields zero overall charge.
Monatomic Ions
Binary Covalent
Common Names
–H2O, water
–NH3, ammonia
–CH4, methane
–C2H6, ethane
–C3H8, propane
Naming Binary
Covalent Compounds
• If the subscript for the first element is
greater than one, indicate the subscript
with a prefix.
– We do not write mono- on the first name.
– Leave the "a" off the end of the prefixes that
end in "a" and the “o” off of mono- if they are
placed in front of an element that begins with
a vowel (oxygen or iodine).
• Follow the prefix with the name of the first
element in the formula.
Naming Binary
Covalent Compounds
• Write a prefix to indicate the
subscript for the second element.
• Write the root of the name of the
second symbol in the formula.
• Add -ide to the end of the name.
Prefixes
mon(o)
di
tri
tetr(a)
pent(a)
hex(a)
hept(a)
oct(a)
non(a)
dec(a)
Roots of Nonmetals
H hydrC carbN nitrP phosphO oxS sulfSe selen-
F fluorCl chlorBr bromI iod-
Forms of Binary
Covalent Names
• prefix(name of nonmetal) prefix(root of
name of nonmetal)ide
•
(for example, dinitrogen pentoxide)
• or (name of nonmetal) prefix(root of
name of nonmetal)ide
•
(for example, carbon dioxide)
• or (name of nonmetal) (root of
nonmetal)ide
•
(for example, hydrogen fluoride)
Writing Binary
Covalent Formulas
• Write the symbols for the elements
in the order mentioned in the
name.
• Write subscripts indicated by the
prefixes. If the first part of the name
has no prefix, assume it is mono-.
Arrhenius Acid
Definition
• An acid is a substance that
generates hydronium ions, H3O+
(often described as H+), when
added to water.
• An acidic solution is a solution
with a significant concentration of
H3O+ ions.
Characteristics of
Acids
• Acids have a sour taste.
• Acids turn litmus from blue to red.
• Acids react with bases.
Strong Acid and Water
When HCl dissolves in water, hydronium
ions, H3O+, and chloride ions, Cl−, ions form.
Solution of a Strong Acid
Types of Acids
• Binary acids have the general
formula of HX(aq)
– HF(aq), HCl(aq), HBr(aq), and HI(aq)
• Oxyacids have the general formula
HaXbOc.
– HNO3 and H2SO4
• Organic (carbon-based) acids
– HC2H3O2
Acetic Acid
Monoprotic and
Polyprotic Acids
• If each molecule of an acid can donate
one hydrogen ion, the acid is called a
monoprotic acid.
• If each molecule can donate two or
more hydrogen ions, the acid is a
polyprotic acid.
• A diprotic acid, such as sulfuric acid,
H2SO4, has two acidic hydrogen
atoms.
• Some acids, such as phosphoric acid,
H3PO4, are triprotic acids.
Strong and Weak Acids
• Strong Acid = due to a completion
reaction with water, generates close
to one H3O+ for each acid molecule
added to water.
• Weak Acid = due to a reversible
reaction with water, generates
significantly less than one H3O+ for
each molecule of acid added to
water.
Weak Acid and Water
Acetic acid reacts with water in a reversible
reaction, which forms hydronium and acetate ions.
Solution of Weak Acid
Strong
and
Weak
Acids
Sulfuric Acid
H2SO4(aq) + H2O(l)
→ H3O+(aq) + HSO4−(aq)
HSO4−(aq) + H2O(l)
H3O+(aq) + SO42−(aq)
Acid Summary
Strong
hydrochloric acid,
HCl(aq)
Weak
hydrofluoric acid
Oxyacid
nitric acid, HNO3
sulfuric acid, H2SO4
other acids
with HaXbOc
Organic acid
none
acetic acid,
HC2H3O2
Binary acid
Names and Formulas
of Binary Acids
• Names have the general form of
hydro(root)ic acid, such as
hydrochloric acid.
• The formulas are usually followed
by (aq), such as HCl(aq).
Names and Formulas
for Oxyacids
• If enough H+ ions are added to a
(root)ate polyatomic ion to completely
neutralize its charge, the (root)ic acid is
formed.
– Nitrate, NO3−, goes to nitric acid, HNO3.
– Sulfate, SO42−, goes to sulfuric acid, H2SO4.
(Note the -ur- in the name.)
– Phosphate, PO43−, goes to phosphoric acid,
H3PO4. (Note the -or- in the name.)
Chemical
Nomenclature
• General procedure for naming
compounds (See Table 5.5 in the
text.)
– Step 1: Decide what type of
compound the name or formula
represents.
– Step 2: Apply the rules for writing
the name or formula for that type of
compound.
Goal:
To develop conversion factors
that will convert between a measurable
property (mass) and number of particles
Measurable Property 1
↓
Number of Particles 1
↓
Number of Particles 2
↓
Measurable Property 2
Mass 1
↓
Moles 1
↓
Moles 2
↓
Mass 2
Molecular Mass
• Whole = sum of parts
• mass of a molecule = sum of the
masses of the atoms in the molecule
• molecular mass = the sum of the
atomic masses of the atoms in the
molecule
Molar Mass For
Molecular Compounds
• Molecular Mass = Sum of the
atomic masses of atoms in one
molecule
⎛ (molecular mass) g molecular compound ⎞
⎜
⎟
1 mol molecular compound
⎝
⎠
Formula Units
• A formula unit of a substance is
the group represented by the
substance’s chemical formula, that
is, a group containing the kinds and
numbers of atoms or ions listed in
the chemical formula.
• Formula unit is a general term that
can be used in reference to
elements, molecular compounds, or
ionic compounds.
Formula Unit Examples
Formula Mass for Ionic
Compounds
• Whole = sum of parts
• Mass of a formula unit = sum of the
masses of the atoms in the formula unit
• Formula mass = the sum of the atomic
masses of the atoms in the formula
Molar Mass For Ionic
Compounds
• Formula Mass = Sum of the
atomic masses of the atoms in a
formula unit
⎛ (formula mass) g ionic compound ⎞
⎜
⎟
1 mol ionic compound
⎝
⎠
Molar Mass Development
General Conversions
Units of
One
Substance
to Units of
Another
Study Sheets
• Write a description of the “tip-off” that
helps you to recognize the type of
problem the calculation represents.
• Write a description of the general
procedure involved in the particular
type of problem.
• Write an example of the type of
calculation.
Sample Study Sheet: Converting
Between Mass of Element and Mass
of Compound Containing the
Element
• Tip-off:
When you analyze the
type of unit you have and the type
of unit you want, you recognize that
you are converting between a unit
associated with an element and a
unit associated with a compound
containing that element.
Sample Study Sheet (2)
• General Steps
– Convert the given unit to moles of the
first substance.
– Convert moles of the first substance
to moles of the second substance
using the molar ratio derived from the
formula for the compound.
– Convert moles of the second
substance to the desired units of the
second substance.
Units of
Element
to Units of
Compound
Calculating Empirical
Formulas
Step 1: If you are not given mass in
grams for each element, convert the
data you are given to grams of each
element.
• This may involve simple unit conversions.
For example, you may be given pounds or
milligrams, which you convert to grams
using dimensional analysis.
• Sometimes you are given the percentage of
each element in the compound. Assume
that you have 100 g of compound, and
change the units of the values given for the
percentages to grams.
Calculating Empirical
Formulas
Step 2: Convert grams of each element to moles
by dividing by the atomic mass of the element.
Step 3: Divide each mole value by the smallest
and round your answers to whole numbers or
common mixed fractions.
Step 4: If you have a fraction after the last step,
multiply all the mole values by the denominator
of the fraction.
Step 5: The resulting mole values correspond to
the subscripts in the empirical formula.
Calculating
Empirical
Formulas
Image
Calculating Molecular
Formulas
Step 1: If necessary, calculate the
empirical formula of the compound from
the data given.
Step 2: Divide the given molecular mass
by the empirical formula mass.
molecular mass
n=
empirical formula mass
Step 3: Multiply each of the subscripts in
the empirical formula by n to get the
molecular formula.
Calculating Molecular
Formulas Image