Chemistry 100(02) Fall 2011
Instructor: Dr. Upali Siriwardane
e-mail: upali@chem.latech.edu
Office: CTH 311 Phone 257-4941
Office Hours: M,W, 8:00-9:00 & 11:00-12:00 a.m Tu,Th,F 9:00 10:00 a.m.
Test Dates: March 25, April 26, and May 18; Comprehensive Fina
Exam: 9:30-10:45 am, CTH 328.
October 3,
October 26,
November 16,
November 17,
2011 (Test 1): Chapter 1 & 2
2011 (Test 3): Chapter 3 & 4
2011 (Chapter 5 & 6)
2011 (Make-up test) comprehensive: Chapters 1-6
9:30-10:45:15 AM, CTH 328
CHEM 100, FALL 2011, LA TECH
3-1
Chapter 3. Chemical Compounds
3.1 Molecular Compounds Page 76
3.2 Naming Binary Inorganic Compounds Page 79
3.3 Hydrocarbons 80
3.4 Alkane and Their Isomers Page 83
3.5 Ions and Ionic Compounds Page 85
3.6 Naming Ions and Ionic Compounds Page 91
3.7 Properties of Ionic Compounds Page 94
3.8 Moles of Compounds Page 98
3.9 Percent Composition Page 103
3.10 Determining Empirical and Molecular Formulas Page
104
3.11 The Biological Periodic Table Page 107
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Chapter 3. KEY CONCEPTS
Chemical Compounds
Molecular, condensed, and
structural formulas
Naming Binary Molecular
Compounds
Straight-chain, branched-chain
constitutional alkane isomers
Hydrocarbons and Alcohols
Ions and Ionic Compounds
Charges on monatomic ions and
names and formulas of polyatomic
ions
Naming and formula of Ions and
Ionic Compounds
Properties of Ionic Compared to
Molecular Compounds
CHEM 100, FALL 2011, LA TECH
Electrolytes and non-electrolytes
Mole of Chemical Compounds
Formula of a hydrated ionic
compound
Percent Composition
Determining Empirical and
Molecular Formulas
Identify biologically important
elements
Identify the important functional
groups in Biomolecules:
Carbohydrates and Fats
3-3
What is a Compounds?
They are made up of a collection of two or more
different atoms and ions.
CO2 - carbon dioxide
SO2, - sulfur dioxide
C3H8 - propane
FeCl3, iron (III) chloride
SnCl2 tin (II) chliride
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Types of Compounds
A) Molecular or Covalent Compounds:
non-metal + non-metal
nonmetal oxide or halides: SO2
Organic compounds: C3H8
B) Ionic compounds:
Metal + non-metal:
a) Type I ionic compound
(fixed charge) NaCl
b) Type II ionic compound
FeCl2 and FeCl3, SnCl2 and SnCl4
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Formula of a Compound
Formula are used to represent
elements and compound.
For molecular compounds, formula
tell how many of each kind of
atom are in a molecule.
For ionic compounds, formula tell
the simples ratio of actions and
anions.
Molecular Weight ? Molecular compounds
and Formula Weight? Ionic compounds
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Types of Chemical Formula
Molecular
Shows ratio of atoms each element in the
compound. E.g ethyl alcohol: C2H6O
Condensed
Shows groups of atoms bonded together in the
formula. E.g ethyl alcohol: CH3CH2OH
Structural
Shows bonding of important groups in the formula
E.g ethyl alcohol:
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Ball and Stick Models of Molecular Compounds
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Models of Ethanol
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Naming Binary
Molecular-Covalent Compounds
For compounds composed of two non-metallic
elements, the more metallic element is listed first.
To designate the multiplicity of an element, Greek
prefixes are used:
mono  1; di  2; tri  3; tetra  4; penta  5;
hexa  6; hepta  7; octa  8
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Simple Binary Molecular Compounds
H2O
NH3
N2O
NO
NO2
N2O4
CO
CS2
SO3
CCl4
PCl5
SF6
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water (common name)
ammonia (common name)
dinitrogen oxide (nitrous oxide)
nitrogen monoxide (nitric oxide)
nitrogen dioxide
dinitrogen tetroxide
carbon monoxide
carbon disulfide
sulfur trioxide
carbon tetrachloride
phosphorus pentachloride
sulfur hexafluoride
3-11
Hydrocarbons
Catenation
The formation of chains of atoms of the same
element.
This key feature of carbon permits a vast
number of compounds to exist.
Four types of hydrocarbons
1) Alkanes (saturated): single C-C bonds
2) Alkenes (unsaturated): double C=C bond
3) Alkynes (unsaturated): triple bond
4) Aromatic (unsaturated): benzene rings
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Classifying Organic Compounds
Examples
Hydrocarbons
Alcohols
Acids
Amines
Ketones
Aldehydes
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Functional Group
C and H only
R-OH
R-COOH
R-NH2
R(C=O)R’
R-CHO
Ending
-ane
-ol
-oic acid
-amine
-one
-al
3-13
Hydrocarbons and Alcohols
alkanes – CnH2n+2
E.g. C5H12 pentane
alkenes – CnH2n
E.g. C2H4
ethene
alkynes – CnH2n-2
E.g. C2H2 ethyne
alcohols – ROH E.g C2H5OH ethanol
where R refers to the hydrocarbon radical backbone
created by substituting an -OH functional group for
a H atom in the hydrocarbon
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Alkanes – CnH2n+2
methane – CH4
ethane – C2H6
propane – C3H8
butane – C4H10
pentane – C5H12
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hexane – C6H14
heptane – C7H16
octane – C8H18
nonane – C9H20
decane – C10H22
3-15
Base names of hydrocarbons
Prefix
Carbons
MethEthPropButPentHexHeptOctNonDec-
1
2
3
4
5
6
7
8
9
10
CHEM 100, FALL 2011, LA TECH
I see much
memorization in
your future!
3-16
Butane
Butane molecules are
present in the liquid
and gaseous states
in the lighter
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As the chain length of Alkane/Alcohols
increases so is the boiling point
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Straight & Branch-Chain Alkanes
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Some
Common
Alkyl
Groups
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What is an Isomer?
Compounds with the same number and type
of atoms but with different arrangements.
Molecular Formula
Condensed formulas.
C5H12
CH3CH2CH2CH2CH3
pentane
CH3CH(CH3)CH2CH3
2-methylbutane
(CH3)4C
2,2-dimethylpropane
All are isomers of C5H12.
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Alkane Isomers is there a formula?
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Naming Branch-Chain Alkanes
Select the longest chain alkane as the base
name
Determine the side chains and give them a
number corresponding to the carbon
number on the base chain
Use Greek prefixes of mono-(1), bi-(2), tri(3),
etc. for multiplicity of same side chain
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Naming Branch-Chain Alkanes
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Alcohol example
CH3CH2CH2CH2OH
C-C-C-C-O-H
Base contains 4 carbon
- Parent alkane name is butane
-remove -e and add -ol
alcohol name - butanol
OH is on the first carbon so 1-butanol
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Ionic Compounds
Characteristics of compounds with ionic bonding:
Compound of metal and non-metal
Composed of ions: cation and anion
non-volatile, thus high melting points
solids do not conduct electricity, but melts (liquid
state) do
many, but not all, are water soluble
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Ions
Ions are charged particles formed by the transfer of
electrons between elements or combinations of
elements.
Cation - a positively charged ion.
Ca
Ca2+ + 2eAnion - a negatively charged ion.
F2 + 2e2F-
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Formation of Ionic Compound, NaCl
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Valance Electrons & Charge on Ions
Outermost electrons (valance electrons) in an
atom lost or gained
metals form positive monatomic ions
non-metals form negative monatomic ions
Ionic compounds have electrical neutrality
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Valence or of Metal Ions
Monatomic Ions (Type I)
Group IA
 +1 Group A #
Group IIA
 +2 Group A #
Non-metals
Group IIB
 -1 (8 - Group B #)
Monatomic Ions (Type II)
Transition metal ionic compounds:
have ions with different charges
E.g. Iron :Fe2+ and Fe3+
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Charges on Some Common
Monatomic Cations and Anions
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Polyatomic Ions
more than one atom joined together
have negative charge except for NH4+
and its relatives
negative charges range from
-1 to -4
Table in the Book
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Polyatomic Ions
Ammonium
perchlorate
cyanide
hydroxide
nitrate
sulfate
carbonate
phosphate
CHEM 100, FALL 2011, LA TECH
NH4+
ClO41CN1OH1NO31SO42CO32PO43-
3-33
Names of Ionic Compounds
1. Name the metal first.
If the metal has more than one oxidation state,
the oxidation state is specified by Roman
numerals in parentheses.
2. Then name the non-metal,
changing the ending of the non-metal to
-ide.
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Metals with multiple charges
Transition metals.
Here it is easier to list the ones that to only have a
single common oxidation state.
All Group 3B - 3+
Ni, Zn, Cd
- 2+
Ag
- 1+
Lanthanides and actinides - 3+ (common)
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Ionic compounds
Some simple ions
Cations
Anions
Na
Cl
-
+
Mg
O
2+
2-
Al
N
3+
3-
Exchange charge as subscripts on the metal and nonmetal
Formula for some ionic compounds
NaCl
MgCl2
Na2O
MgO
Na3N
Mg3N2
CHEM 100, FALL 2011, LA TECH
AlCl3
Al2O3
AlN
Give the simple ratio
3-36
Nomenclature
NaCl
Fe2O3
NH4NO3
KClO4
CaCO3
NaOH
AgNO3
Mg(C2H3O2)2
Co2(SO4)3
KI
Mg3N2
CHEM 100, FALL 2011, LA TECH
NaCl sodium chloride
Fe2O3 iron(III) oxide
NH4NO3 ammonium nitrate
KClO4 potassium perchlorate
CaCO3 calcium carbonate
NaOH sodium hydroxide
AgNO3 silver nitrate
Mg(C2H3O2)2 magnesium acetate
Co2(SO4)3 cobalt(III) sulfate
KI potassium iodide
Mg3N2 magnesium nitride
3-37
Ionic Crystal Lattice
NaCl “table salt”
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Cleaving NaCl
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Electrical
Conductivity of
Ionic Solution
Electrolytes
Aqueous solutions conducts
electricity
strong-electrolytes
weak-electrolytes
Non-electrolytes
Aqueous solutions do not
conducts electricity
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Naming Acids
formula starts with H
Hydrochloric
acid
HCl
Nitric acid
HNO3
Sulfuric acid
H2SO4
HClO3
Chloric acid
H3BO3
Boric acid
H3PO4
Phosphoric acid
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Names of acids and ions
HClO hypochlorous
HClO2 chlorous
HClO3 chloric
HClO4 perchloric
ClO¯ ”hypochlorite
ClO2¯ chlorite
ClO3¯ chlorate
ClO4¯ perchlorate
HNO3 nitric
HNO2 nitrous
NO3 ¯ nitrate
NO2 ¯ nitrite
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Naming bases
formula ends with OH
NaOH
sodium hydroxide
Ba(OH)2
barium hydroxide
KOH
potassium hydroxide
NH4OH
Ca (OH)2
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ammonium hydroxide
calcium hydroxide
3-45
Percentage Composition
description of a compound based on the percent
relative amounts of each element in the
compound
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% Element Composition in
Compounds from Formula
n x Gram Atomic weight
% mass = --------------------------------------- x 100
formula weight (GMW, GFW)
n = subscript of the element in the formula
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Example: What is the percent composition of
carbon in chloroform, CHCl3, a substance once
used as an anesthetic?
MM = 1(gaw)C + 1(gaw)H + 3(gaw)Cl
= (12.011 + 1.00797 + 3  35.453)amu
= 119.377amu
1(12.011)
%C =
 100 = 10.061% C
119.377
1(1.00797)
%H =
 100 = 0.844359% H
119.377
3(35.453)
%Cl =
 100 = 89.095% Cl
119.377
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Example: What is the percent composition
of chloroform, CHCl3, a substance once
used as an anesthetic?
%C =
10.061% C
%H =
0.844% H
%Cl = 89.095% Cl
100.00
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Mass percent of element in C6H12O6
Molar Mass = 180.16 g/mol
%C =
%H =
%O =
6 x 12
--------- x 100 =
180.16
12 x 1.01
------------- x 100 =
180.16
6 x 16.00
------------ x 100 =
180.16
CHEM 100, FALL 2011, LA TECH
40.00% C
6.73% H
53.29% O
----------100.02%
3-50
What is Empirical Formula?
Simple whole number ratio of each atom
expressed in the subscript of the
formula.
Molecular Formula = C6H12O6 of glucose
Empirical Formula = CH2O
Empirical formula is calculated from % composition
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How do you get Empirical
Formula from %
composition and vice
versa?
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Example: The burning of fossil fuels in
air produces a brown-colored gas, a
major air pollutant, that contains 2.34 g
of N and 5.34 g of O. What is the
empirical formula of the compound?
%N =
%O =
2.34
2.34 + 5.34
5.34
2.34 + 5.34
CHEM 100, FALL 2011, LA TECH
 100 = 30.5% N
 100 = 69.5% O
3-53
Empirical Formula from % composition
%N = 30.5% N
%O = 69.5% O
Relative # Atoms
Multiply
by Integer
% (%/gaw) Divide by Smaller
N 30.5 30.5/14.0067 = 2.18 2.18/2.18 = 1.00 11.001
O 69.5 69.5/15.9994 = 4.34 4.34/2.18 = 1.99 11.992
Empirical Formula  NO2
Empirical Formula Weight = 46.0
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Molecular formula from Empirical
formula
Molecular Formula = n x empirical Formula
Molecular weight
180
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Molecular Formula from Empirical
Empirical Formula Weight
30
Molecular Formula = (CH2O)n = (CH2O)6
Molecular Formula = C6H12O6 of
glucose
Molecular Formula Weight = 180
Molecular Formula Weight
n = ---------------------- =
Empirical Formula Weight
CHEM 100, FALL 2011, LA TECH
180
------ = 6
30
3-56
Example: A colorless liquid used in
rocket engines, whose empirical
formula is NO2, has a molar mass (MW)
of 92.0. What is the molecular formula?
FM = 1(gaw)N + 2(gaw)O = 46.0
MM
92.0
X=
=
=2
FM
46.0
thus MF = 2  EF
N2O4
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Combustion Analysis
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Example Benzoic acid is known to
contain only C, H, and O. A 6.49-mg sample
of benzoic acid was burned completely in a
C-H analyzer. The increase in the mass of
each absorption tube showed that 16.4-mg
of CO2 and 2.85-mg of H2O formed. What is
the empirical
formula of benzoic acid?
(16.4-mg of CO2 )(12.01-mg C)
#mg C =
= 4.48-mg C
(44.01-mg CO2)
%C =
4.48-mg C
 100 = 68.9% C
6.49-mg sample
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Example Benzoic acid is known to
contain only C, H, and O. A 6.49-mg sample
of benzoic acid was burned completely in a
C-H analyzer. The increase in the mass of
each absorption tube showed that 16.4-mg
of CO2 and 2.85-mg of H2O formed. What is
the empirical
formula of benzoic acid?
(2.85-mg of H2O )(2.02-mg H)
#mg H =
= 0.319-mg H
(18.02-mg H2O)
%C =
0.319-mg H
 100 = 4.92% H
6.49-mg sample
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Example Benzoic acid is known to
contain only C, H, and O. A 6.49-mg sample
of benzoic acid was burned completely in a
C-H analyzer. The increase in the mass of
each absorption tube showed that 16.4-mg
of CO2 and 2.85-mg of H2O formed. What is
the empirical formula of benzoic acid?
68.9% C
4.92% H
% O = (100 - (68.9% C + 4.92% H) = 26.2% O
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Example Benzoic acid is known to
contain only C, H, and O. A 6.49-mg sample
of benzoic acid was burned completely in a
C-H analyzer. The increase in the mass of
each absorption tube showed that 16.4-mg
of CO2 and 2.85-mg of H2O formed. What is
the empirical formula of benzoic acid?
Relative # Atoms
%
C 68.9
H 4.92
O 26.2
(%/gaw)
68.9/12.0 = 5.75
4.92/1.01 = 4.87
26.2/16.0 = 1.64
Divide by Smallest
5.75/1.64 = 3.51
4.87/1.64 = 2.97
1.64/1.64 = 1.00
Multiply by Integer
3.51  2 = 7
2.97  2 = 6
1.00  2 = 2
C7H6O2
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Biological Periodic Table
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Important Functional Groups
A functional group is a group of
atoms consisting of O, H, C, N, P and
S attached to a carbon skeleton of
an alkane that affect its properties
and reactivity.
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Classifying Organic Compounds
Hydrocarbons C and H only
Alcohols
R-OH
Acids
R-COOH
Amines
R-NH2
Ketones
R(C=O)R’
Aldehydes
R-CHO
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Carbohydrates
Carbohydrates are sugars and long polymers of
sugars, such as starches and cellulose.
Monosaccharides are single sugar units and are
also called “simple sugars”.
Disaccharides consist of two sugar units linked
together.
Polysaccharides are long polymers made of
individual sugar units, usually of the monomer
glucose.
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Glucose
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Sucrose
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Fats
Fats are large molecules made from two types of
building blocks,
Glycerol (a polyalchohol)
Fatty acids (long hydrocarbon chains of 16-18 C
with a single carboxylic acid group at one end).
Fats are not polymers. Structure of a fat, also
known as a triacylglycerol
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Tristearin - Glycerol - Stearic Acid
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Saturated/Unsaturated fatty acids
Unsaturated fatty acids
contain C=C double
bonds may take one
or two forms at a
double bond.
In the cis form
the chain
bends at an angle of
about 30 degree,
producing a kink.
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