MODULE IN

CHEMICAL ENGINEERING

CHEM
2121

Department of Chemical Engineering

SCHOOL OF ENGINEERING AND ARCHITECTURE

 CHEM 2121
COURSE LEARNING OUTCOMES
At the end of the module, you should be
able to:

1. Use the electronic effects

(hyperconjugation, inductive
effect, resonance) or structural
effects to predict chemical
behavior of organic compounds
and recognize how extensively
organic substances affect human
lives and the environment.

2. Write/draw molecular structures

and apply the International Union
of Pure and Applied Chemistry
rules in naming organic
compounds.

3. Predict the physical properties of

organic molecules belonging to
the following classes of organic
compounds: alkane, alkyl halide,
alcohols, esters, alkenes, alkynes,
aromatic rings, aldehydes,
ORGANIC ketones, carboxylic acids and
their derivatives, and amine
CHEMISTRY FOR functional groups.

CHEMICAL 4. Develop basic skills illustrating

multi-step mechanism for the
synthesis and analysis of organic
ENGINEERS compounds showing
conversion of one organic
the

LECTURE compound to another.

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 Source: https://todayinsci.com/QuotationsCategories/O_Cat/OrganicChemistry-
Quotations.htm

COURSE INTRODUCTION

This is a 4-unit course which is designed to provide students with the

fundamental concepts of Organic Chemistry and its applications to the field of
Chemical Engineering.
The course includes the study and classifications, nomenclature, occurrence,
preparation, as well as, physical and chemical properties of organic compounds. It
also explains the important role of some organic molecules in the human life
processes. It also includes an overview of the basic concepts of biochemistry

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 MODULE
Cover Letter to the Student

Every living organism is made of organic chemicals. The proteins that make up
your hair, skin, and muscles; the DNA that controls your genetic heritage; the foods
that nourish you; and the medicines that heal you are all organic chemicals. Anyone
with a curiosity about life and living things, and anyone who wants to be a part of
the remarkable advances now occurring in medicine and the biological sciences,
must first understand organic chemistry. The course CHEM 2121: Organic Chemistry
for Chemical Engineers Lecture introduces the students to the broad study on the
different organic compounds, its physical and chemical properties and their
applications in industrial setting.
To ensure that you will demonstrate the learning outcomes, this course
originally designed to be delivered in 72 contact hours was structured into three
modules. Each module contains several units with its own topic learning outcomes
and topic outline. Each unit contains activities designed using the 5E constructivist
model of learning, developed by Rodger Bybee, that encourages students to
engage, explore, explain, elaborate, and evaluate their learning of topics covered
therein. This means that at the end of each unit, each module, and the course as a
whole, you will be assessed on your progress in attaining the course learning
outcomes. Outcomes based education dictates that only when you can clearly
demonstrate the course learning outcomes by the end of this course, can you be
given a passing mark. The modules that form the building blocks to help you attain
the course learning outcomes are as follows:

Summary of Contents

Module 1: Structure and Bonding, Saturated Hydrocarbons and Unsaturated

Hydrocarbons
Unit 1 Introduction and History of Organic Chemistry; Overview of Organic
Compounds
Unit 2 Molecular Geometry, Hybridization, Covalent Bond, Functional
groups
Unit 3 Saturated Organic Hydrocarbons
Unit 4 Unsaturated Organic Hydrocarbons

Module 2: Aromatic Hydrocarbons and Oxygen - and Sulfur-containing

Compounds
Unit 1 Aromatic Hydrocarbons
Unit 2 Alcohols, Phenols and Ethers
Unit 3 Aldehydes and Ketones

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 Unit 4 Thiols

Module 3: Carboxylic Acids and Nitrogen-Containing Compounds

Unit 1 Carboxylic Acids and its Derivatives
Unit 2 Nitrogen-Containing Compounds

Presentation Format:
The course consists of 3 modules, over a period of 54 days to be taken via the
correspondence mode (offline). Participants will be sent a copy of the modules via
courier. Course reading materials will be stored in a memory stick (flash drive) for the
student`s reference. Interaction and queries with the instructor will be done through
text messages using a cellular phone. Outputs will be collected and be saved in the
same memory stick to be sent back to the instructor via courier. For student
presentations, student will be asked to take a video of themselves and save the
presentation in the memory stick as well for viewing by the instructor.
Some modules may involve a practical component. For each module there
will be an initial reading assignment along with coursework, quizzes or problems to
be handed in and in some cases, practical exercises.

MODULE 1: Structure and Bonding, Saturated

Hydrocarbons and Unsaturated Hydrocarbons
At the end of the module, you should be able to:
 Differentiate the properties of organic and inorganic compounds and review
of some basic concepts.
 Differentiate atomic and molecular orbitals and apply the hybridization of
carbon, nitrogen and oxygen. Identify, understand, and recognize what are
characteristics of a covalent bond.
 To be able to name, draw organic structures using systematic or common
name and be familiar with various attachments on saturated aliphatic and
cyclic hydrocarbons.
 To understand the concept of isomerism and other important reaction
mechanisms.
 Identify common and important sources, uses of alkanes and their applications
in industrial setting.
 Demonstrate proficiency in naming and structure writing of unsaturated
hydrocarbons (Alkenes and Alkynes).
 Analyze and understand physical and chemical properties of unsaturated
hydrocarbons including their preparations addition reactions, isomerism.
Identify common and important sources, practical uses and their applications
in industrial setting

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 Introduction
This module is the first of three modules that deal with the subject of organic
chemistry and organic compounds. Organic compounds are the chemical basis for
life itself, as well as an important component of the basis for our current high standard
of living. Proteins, carbohydrates, enzymes, and hormones are organic molecules.
Organic compounds also include natural gas, petroleum, coal, gasoline, and many
synthetic materials such as dyes, plastics, and clothing fibers. This module addresses
the structure and bonding of organic compounds, saturated hydrocarbon and
unsaturated hydrocarbons.

Unit 1: Introduction and History of Organic Chemistry;

Overview of Organic Compounds
UNIT LEARNING OUTCOMES
 Determine and differentiate organic compound and inorganic compounds.
 Explain the differences in properties between organic and inorganic
compounds.

ENGAGE

"I can no longer, so to speak, hold my

chemical water and must tell you that I can
make urea without needing a kidney,
whether of man or dog; the ammonium salt
of cyanic acid is urea."
Wöhler (1800-1882)

Reflection 1.1: Identify the following compounds as inorganic or organic compound.

1. Water 6. Quartz
2. Salt 7. Carbon Dioxide
3. Sugar 8. Urea
4. Diamond 9. Milk
5. Coal 10. Vitamins
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 EXPLORE

Introduction
 ORGANIC CHEMISTRY – the study of the compounds of carbon
 The location of carbon in the middle of the periodic table and its low atomic
mass makes it ideal as the major element for biological compounds.
 The element CARBON has the capability to form many different compounds,
such as gasoline, coal, medicines, shampoos, plastic bottles, perfumes,
flavorings, fabrics, among the variety of consumer products.
 The foods we eat are composed of many different organic compounds that
supply us with fuel for energy and the carbon atoms needed for building and
repairing the cells of our bodies.

Brief History
 Originally, “organic” literally means “derived from living organisms’
 Vitalism – belief that natural products (sugar, starch, waxes and plant oils,
among others) needed a “vital force” to create them
 JONS JAKOB BERZELIUS (1808) – the first to use the term organic
 Organic compounds (isolated from plants and animals); inorganic
compounds were found in minerals
 Organic compounds contained a “vital force” as a result of their origin in living
sources
 1816: Michel Chevreul found that soap could be separated into several pure
organic compounds termed as fatty acids.

 1828: Friedrich Wohler converted an inorganic salt into an “organic”

substance. This organic substance is urea H2NCONH2
 Marcellin Berthelot showed that all classes of organic compounds could be
synthesized that the vital force theory finally disappeared.
 Friedrich August Kekulé (1858): Discovered that carbon has a valence of 4
and can unite with itself. This concept, called catenation, is necessary for the
structural theory of organic chemistry.
 In 1916, Gilbert N. Lewis introduced the concept of a bond formed by sharing
electrons. He called a bond composed of shared electrons pairs a covalent
bond.
 In 1923, Lewis came up with the idea that a molecule that accepts an electron
pair should be called an acid and a molecule that donates an electron pair
should be called a base. These are called Lewis acids and Lewis bases to this
day.
 Erich Huckel developed theories of bonding and orbitals and also speculated
on the nature of the C=C unit.

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 EXPLAIN

Comparison between organic and inorganic compounds

Criteria Inorganic Organic
Composition Contain metals in salts All are carbon
and oxides compounds

Elements involved All elements in the Mainly C, H, O, N, S,

periodic table P, halogens (F, Cl, Br,
I)
Chemical Bond Ionic or polar bonds Covalent bond

Rates of reaction Fast to very fast Slow, moderately fast

to explosive
Combustibility/Flammability Non-combustible/ Highly combustible/
Non-flammable Highly flammable

Melting Point High Low

Boiling Point High Low

Structure Simple Complex
Solubility
In water or polar Yes No
solvents
In organic solvents No Yes
or non-polar
solvents
Electrical conduction Many are electrolytes Most are non-
electrolytes.
Volatility Non-volatile Highly volatile
Stability towards heat Generally stable Less stable towards
heat

ELABORATE

The Element Carbon

Carbon is not an abundant element; it only constitutes 0.027% of the earth’ s
crust. Carbon can be in the form of crystalline carbon or amorphous carbon.

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 Crystalline Carbon
 GRAPHITE – soft, black slippery solid having metallic luster and conducts
electricity. It consists of parallel sheets of carbon atoms held together by Van
der Waals forces (ρ = 2.25 g/cm 3).
 DIAMOND – clear hard solid, denser than graphite (ρ = 3.51 g/cm3). At very
high temperature and pressure, graphite converts to diamond and mainly
used in cutting, grinding, and polishing tools.
 BUCKMINSTERFULLERENE – molecular form of carbon discovered in the mid-
1980s, consisting of C60. it has a cage-like fused-ring structure (truncated
icosahedron) resembling a soccer ball, made of 20 hexagons and 12
pentagons. Uses: antioxidants; antiviral agents; drug delivery and gene
delivery; photosensitizers in photodynamic therapy; solar cells; protective eye
wear; hardening agents.
Amorphous Carbon
 CARBON BLACK – used as a pigment in black inks, paints, plastics; reinforcing
filler in tires and rubber products
 CHARCOAL – formed when wood is heated in the absence of air. Activated
charcoal is a pulverized form whose surface is cleaned by heating with steam
and widely used as an adsorbent.
 COKE – high carbon content, few impurities used as a reducing agent in
smelting iron ore; manufacture of water gas (CO + H2)
Uniqueness of Carbon
 Can bond with another carbon atom forming long chains of carbon atoms
 Carbon chains can have branches or form ring structures of various sizes
 Carbon can bond strongly to other elements such as hydrogen, oxygen,
nitrogen, and halogens, and can be arranged in different ways; the reason
why there are so many organic compounds.
 Carbon can form double bonds and triple bonds with other carbon atoms or
with non-metals.
 Remember: Carbon have a four bond requirement.

Non metals most often present in organic substances:

H, O, N, S, P, and Halogens (F, Cl, Br, I)

Metals commonly found in organic compounds:

Fe, Mg, Zn, Cu, Pt, Na, K

Self-Assessment 1.1: Is the statement “Life comes from Life” applicable to organic
Chemistry? Prove your answer through related Journal.
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 EVALUATE

Graded Test 1: Concept Analysis/Application

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 Unit 2: Molecular Geometry, Hybridization, Covalent Bond,
Functional Groups
UNIT LEARNING OUTCOMES
 Differentiate atomic and molecular orbitals
 Apply the hybridization of carbon
 Identify, understand, and recognize what are characteristics of a covalent
bond.

ENGAGE

Below is a simple illustration of an atom.

Reflection 1.1: On your own words define what is an atom? In reference, of the photo
above determine the parts of an atom.
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EXPLORE

Introduction
ATOM
Atoms are the basic building blocks of matter that make up everyday objects.
It is composed of a small dense nucleus, diameter 10-14 – 10-15 m and an extranuclear
space, diameter 10-10 m. The nucleus contains positively charged protons and a no
charged neutron; and most of the mass of the atom. The extranuclear space
contains negatively charged electrons.

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 Electron Configuration of Atoms
 Electrons are confined to regions of space called principle energy levels
(shells).
 Each shell can 2n2 electrons where n is the number of the shell (n = 1,2,3,4….)

 Shells are divided into subshells called orbitals, which are designated by the
letters s, p, d, f….
o -s (one per shell)
o -p (set of three per shell 2 and higher)
o -d (set of five per shell 3 and higher)

Ways of Writing Electron Configuration

 Orbital box notation

 Spectroscopic notation (Longhand way)

C = 1s22s22p2
 Noble Gas Core notation (Shorthand way)
C = [He] 2s22p2

LEWIS DOT STRUCTURE

 Gilbert N. Lewis
 Valence shell: the outermost electron shell of an atom
 Valence electrons: electrons in the valence shell of an atom; these electrons
are used to form chemical bonds and in chemical reactions.
 Lewis dot structure:
o the symbol of the atom represents the nucleus and all inner shell
electrons
o dots represent valence electrons

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  Lewis Dot Structure for Element of Family A:

Lewis Model of Bonding

 Atoms bond together so that each atom acquires an electron configuration
the same as that of the noble gas nearest it in atomic number.
o An atom that gains electrons becomes an anion
o An atom that loses electrons becomes a cation
o The attraction of an anions and a cation leads to the formation of an
ionic bond
o An atom may share electrons with one or more atoms to complete its
valence shell; a chemical bond formed by sharing one or more pairs of
electrons is called a covalent bond
o Bonds may be partially ionic or partially covalent; these bonds are
called polar covalent bonds

QUANTUM MECHANICS
 As it has been studied previously, electrons in atoms are treated as waves
effectively than as compact particles in circular or elliptical orbits. Such particles
like electrons, atoms or molecules do not obey Isaac Newton’s Law but rather
obeys a different kind of mechanics called quantum mechanics.
 One of the underlying principles of quantum mechanics is that we cannot
determine precisely the paths that electrons follow as they move about atomic
nuclei (HEISENBERG UNCERTAINTY PRINCIPLE).
 Because of this, scientists resort to statistical approach and speak of the
probability of finding an electron within specified region in space ( ATOMIC
ORBITAL).
 Quantum numbers are used to designate the electronic arrangements in all
atoms (ELECTRONIC CONFIGURATION) and play important roles in describing the
energy levels and the shapes of orbitals that describe the distributions of electrons
in space.
4 Quantum Numbers:
1. PRINCIPAL – indicates the size of the orbital
2. AZIMUTHAL (or angular momentum) – indicates the shape of the orbital
3. MAGNETIC – indicates the orientation or position of the orbital
4. SPIN – indicates the spin of the electron

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 REVIEW OF TERMS AND DEFINITIONS
 Orbitals - They represent the probability of finding an electron in any one place.
They correspond to different energies. So an electron in an orbital has definite
energy. Orbitals are best described with quantum mechanics.
 Molecular Orbitals – formed as a result from the overlap of two atomic orbitals,
wherein a pair of electrons occupying.
 Atomic Orbitals – the region in space just outside the nucleus of the atom where
the probability of finding the electrons is at the highest (95%).

Atomic Orbitals
 The energy levels about the nucleus contain group of these atomic orbitals.
 Each orbital (s, p, d, and f) has a unique energy associated with it, can contain a
maximum of two electrons and varies in shape and spatial orientation.
 We are mainly concerned with the s and p orbitals since most of the elements
found in organic molecules have their electrons in the 1s, 2s, and 2p orbitals.
The s-orbital
The s orbital is spherical, like a fuzzy hollow ball with its center at the nucleus of the
atom.

It contains no nodes The 2s atomic orbital has a For any atom there is only
because it is the closest to small region of electron one 3s orbital. There are
the nucleus. It has the density surrounding the two spherical nodes in the
lowest energy of all the nucleus, but most of the 3s orbital.
atomic orbitals electron density is farther
from the nucleus, beyond
a node.
The p-orbital
 Each p orbital consists of a “dumbbell” or “teardrop” shape on either side of the
nodal plane that runs through the center of the nucleus.
 Their orientation is 90 ˚ from each other in the three spatial direction and have
identical energies and shapes.
 Chemists call them as degenerate orbitals.
 Because electrons in the three 2p orbitals are farther from the nucleus than those
in the 2s orbital, they are at a higher energy level.
 There are three p orbitals of equal energy, designated px, py, and pz.

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  Each p orbital is dumbbell or “teardrop” shaped. Each consists of two lobes with
atomic nucleus lying between them and each has a nodal plane at the nucleus,
where the probability of the electron’s location is zero.

The d-orbital and f-orbital

There are five d orbitals, referred to as dz2, dxy, dxz, dyz , and dx2-y2

The shapes of f-orbitals are quite complicated.

Higher d and f orbitals are utilized by elements further down in the periodic table .
These are further discussed by inorganic chemists.

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 Molecular Orbitals
 Molecular Orbitals – form as a result from the overlap of two atomic orbitals or
fusion of 2 atomic orbitals (AO’s)
 As with AO’s, a molecular orbital may not contain more than two electrons.
 The molecular orbital represents a lower energy state for the system than do two
separate AO’s at the characteristic internuclear distance.
 Energy is liberated during the overlap, and a stable covalent bond is formed.
TYPES OF MOLECULAR ORBITAL
1. Sigma (σ) molecular orbital – orbital that is symmetrical about the molecular axis.
The two electrons in it are called the σ bonds.
A sigma molecular orbital may be formed by the direct or head-on overlap
the following orbitals.
a.) Two 1s atomic orbitals

b.) Two px atomic orbitals

c.) 1s and px atomic orbitals

Examples of Sigma Bond Formation:

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 2. Pi (π) molecular orbital – In a π molecular orbital, the electron density is
concentrated above and below the line joining the two nuclei of the bonding atoms.
The electrons in it are called π electrons and the bond is referred to as π bond. A
double bond is one σ bond and one π bond, a triple bond consists of one σ bond
and two π bonds.
A π molecular orbital may be formed by the sideways overlap of the following
orbitals.
a.) Two pz atomic orbitals

b.) Two py atomic orbitals

c.) py or pz and dxz atomic orbitals

EXPLAIN

HYBRIDIZATION – the process of mixing different types of AO’s to produce a set of

equivalent orbitals known as HYBRID ORBITALS.
Most common hybrid orbitals:
a) Sp Ex. C2H2, BeCl 2
b) Sp 2 Ex. C2H4, BF3
c) Sp 3 Ex. CH4, H2O

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 Hybridization involving d-orbitals
d) sp3d Ex. PF5, SF4
e) sp d
3 2 Ex. SF6, ClF5

MULTIPLE BONDS:
 Single bonds – are σ bonds (sp3)
 Double bonds – 1 σ & 1 π bond (sp2)
 Triple bonds – 1 σ & 2 π bonds (sp)

Characteristics of sp hybrid orbital

 the shape of sp hybrid orbital is like a bowling pin
 the 2 sp hybrid orbital form a linear shape
 the bond angle is 180°
 each sp hybrid orbital has ½ s and ½ p character
 forms 2 sigma bonds and 2 pi bonds
 forms a single bond and a triple bond or two double bonds
 the two unhybridized 2p orbitals are perpendicular to each other and to the line
through the two sp hybrid orbitals
Example: The orbital structure of acetylene

Source: Chemistry the Central Science – Brown, Lemay, Bursten, Murphy,

Woodward.mobi

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 Characteristics of sp2 hybrid orbital
 the shape of 1 sp2 hybrid orbital is like a bowling pin
 the 3 sp2 hybrid orbitals form a trigonal planar shape
 the bond angle is 120°
 each sp2 hybrid orbital has 1/3 s and 2/3 p character
 forms 3 sigma bonds and 1 pi bond
 forms 2 single bonds and a double bond
 the unhybridized 2p orbital is perpendicular to the plane of the sp 2 hybrid orbitals
Formation of sp2 hybrid orbitals

Example: The orbital structure of ethylene, CH2=CH2

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 Characteristics of sp3 hybrid orbital
 the shape of 1 sp3 hybrid orbital is like a bowling pin
 the 4 sp3 hybrid orbitals form a tetrahedron
 the bond angle is 109.5°
 each sp3 hybrid orbital has ¼ s and ¾ p character
 all bonds formed are sigma bonds
 all bonds formed are single bonds (4 single bonds)
Formation of sp3 hybrid orbital

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 Geometric Arrangement of Hybrid Orbitals:

Electron Domain Geometries as the Function of Number Electron Domains

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 Hybridization for Other Compounds
 If total valence electron (TVE) > 8
Total valence Electron
Hybridization state = 8
Example: CCl4 TVE = 32/8 = 4; therefore, sp3
If quotient is 2 ---- sp 5 ----- sp3d
3 ----- sp2 6 ----- sp3d2
4 ----- sp 3 7 ----- sp3d3
 If total valence electron (TVE) < 8
Total valence Electron
Hybridization state = 2
When H-atoms surrounds the central atom, use TVE/2.
Example: H2OTVE = 8/2 =4, therefore, sp3

Steric Effects
 Nonbonding interactions that influence the shape and reactivity of ions and
molecules
 Indicative of the number of bonds attach to an atom
 Aid in determining molecular geometry
Example: CH3CHO
H 4 steric values; sp3
|
H–C–C=Ӧ
| |
H H 3 steric values; sp2

Characteristics of a Covalent Bond

A) BOND POLARITY
Measure of the unevenness of the distribution of electrons due to unequal sharing of
electrons
Factors affecting bond polarity:
a) ELECTRONEGATIVITY – ability of an atom to attract electrons toward itself; e-
attracting character
EA − EB
% ionic character = x100
EA
Significance:
 The greater the electronegativity difference, the more polar is the bond.
 Electronegativity 𝛂 melting point, boiling point, solubility
b) Formal Charge (FC) – determines which atom is the (+) charge or (-) charge.
FC of an atom = group no. – ½ shared e- – no. of unshared e-
Ex. NH3: For N: 5 – 3 – 2 = 0
For H: 1 – 1 – 0 = 0
NH4 :+ For N: 5 – 4 – 2 = + 1
For H: 1 – 1 – 0 = 0

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 B. BOND LENGTH
Distance between the nuclei of the atoms involved in the bond
Measured in Angstrom = 1 x 10 -10 m
Factors affecting bond length:
a) E.N. difference
increase electronegativity → increase bond polarity → decrease bond length
b) Number of pi bonds
Increase no. of π bonds → increase attraction → decrease bond length
C. BOND ENERGY or BOND STRENGTH
 Also known as bond enthalpy, the energy required to break the only bond in the
molecule or to dissociate the bonded atoms to their ground state
 Measured in Kcal/mole or KJ/mole
 A molecule with strong chemical bonds has less tendency to undergo chemical
changes
 These molecules are chemically stable.
Factors affecting bond length:
a) Electronegativity
Increase electronegativity → increase attraction → decrease bond length →
increase bond energy
b) Number of π bonds
Increase number of π bonds → increase attraction → decrease bond length →
increase bond energy
c) The shorter bond length, the stronger is the bond
General Comparison:
C–C C=C C≡C

Bond length (Angstrom) 1.54 Ả 1.34 Ả 1.20 Ả

Bond strength (KJ/mol) 348 614 839
D. BOND ORDER -number of chemical bonds between a pair of atoms and indicates
the stability of a bond.
E.g. Bond Order
N≡N 3
H–C≡C–H the C-to-C bond is 3
the C-H is 1
Significance:
 A high bond order indicates more attraction between electrons.
 Also means that the atoms are held together more tightly, therefore, the more
stable is the molecule.
Bond Order for Polyatomic Ions
Steps:
1. Draw the Lewis structure
2. Count total number of bonds

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 3. Count the bond groups bet. Individual atoms
4. #2 ÷ #3

E.g.: NO3―
: O: ̶
║
N
:O: :O:
˚˚ ˚˚
4 (total no. of bonds)
Bond lenght = = 1.3333
3 (bond group between individual atoms)
E. BOND ANGLE
 Distance between 2 bonds; the angles made by the lines joining the nuclei of
the atoms in a molecule
 Sp3 - 109.5o ; sp2 – 120o ; sp – 180o
 Significance:
 Decrease bond angle → increase bond energy → more stable compound

ELABORATE

Graded Assignment 1.2: Concept Application: Show all necessary computations

and or illustrations.
Predict the (1) bond angles around each carbon atom; (2) give the hybridization of
each carbon atom; (3) bond order of each molecule:
a) CO2 b) CO3 -2 c) HCN
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Graded Test 1.2 FAMILY NAME, GIVEN NAME

EVALUATE

Graded Test 1: Concept Analysis/Application

Save it in the memory stick in PDF format with the filename:
Graded Test1 FAMILY NAME, GIVEN NAME

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 Unit 2: Saturated Organic Hydrocarbons
UNIT LEARNING OUTCOMES
 Name, draw organic structures using systematic or common name and be
familiar with various attachments on saturated aliphatic and cyclic
hydrocarbons
 Understand the concept of isomerism and other important reaction
mechanisms
 Identify common and important sources, uses of alkanes and their
applications in industrial setting

ENGAGE

Source: http://petrochemksa.com/
Crude oil (petroleum) constitutes the largest and most important natural source for
saturated hydrocarbons, the simplest type of organic compound.

Reflection 1.3: Identify one alkane found at home and take a selfie.
Save it in the memory stick in PDF format with the filename:
Reflection 1.3 FAMILY NAME, GIVEN NAME

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 EXPLORE

Introduction
The field of organic chemistry encompasses the study of hydrocarbons and
hydrocarbon derivatives. Thus one classification of organic compounds is based on
its composition.

Source: General, Organic and Biological Chemistry by H. Stoker

Hydrocarbon is a compound that contains only carbon atoms and hydrogen
atoms. Thousands of hydrocarbons are known. A hydrocarbon derivative is a
compound that contains carbon and hydrogen and one or more additional
elements. Additional elements commonly found in hydrocarbon derivatives include
O, N, S, P, F, Cl, and Br. Millions of hydrocarbon derivatives are known. The
hydrocarbon derivatives can be further classified as Oxygen-containing
compounds, Nitrogen-containing compounds and Sulfur-containing compounds.
Organic compounds can also be classified into based on structure and based
on function.
Classification of Organic Compound Based on Structure

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  Aliphatic organic compound containing carbon and hydrogen joined
together in straight chains, branched chains, or non-aromatic rings.
 Acyclic compound is a compound with a linear structure, rather than a cyclic
one.
 Cyclic hydrocarbon is a hydrocarbon in which the carbon chain joins to itself
in a ring.
 Alicyclic compound is a kind of compound which is aliphatic and cyclic too.
 Heterocyclic compound or ring structure is a cyclic compound that has atoms
of at least two different elements as members of its ring(s).
 Aromatic hydrocarbons are a special class of unsaturated hydrocarbon
based on a six carbon ring moiety called benzene.

Classification of Organic Compounds Based on Functional Groups

Functional Groups
 Atoms or groups of atoms of an organic molecule that undergo predictable
chemical reactions
 These are the units by which organic compounds are classified into the
different/groups families of compounds
 Serves as a basis of naming organic compounds

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 General Characteristics/Properties of Organic Compounds
 Hydrocarbon occur abundantly in nature
 Chains can be very long or very short
 The length of carbon chain affects their physical and chemical properties
 Boiling points and melting points rise as the number of carbon atoms increases
 Hydrocarbons burn in oxygen to produce carbon dioxide and water.
 The products of combustion differ between complete (Hydrocarbon + Oxygen
 Carbon Dioxide + Water) and incomplete combustion (Hydrocarbon + O2
 CO + H2O)
 The higher the molar mass of the hydrocarbon molecule and more carbon
atoms it contains
o The higher its boiling point
o The less easily it turns into vapour i.e it is less volatile
o The less easily it flows i.e it is more viscous
o The less easily it ignites i.e it is less flammable
 For example:
o C1 – C5 = gaseous
o C6 – C18 = liquid to greases (semi-solids)
o C20 and more = solids (artificial asphalts & paraffin)
o C100 and more = plastics
 Common hydrocarbons:
o LPG
o Candle wax
o Local anesthetics
o Petroleum jelly
o Acetylene torch

EXPLAIN AND ELABORATE

Alkanes
 Single-bonded hydrocarbons; saturated hydrocarbons; names end in –ane;
main source of natural gas.
 Aliphatic hydrocarbons – “fat” like
 The name is derived from Latin parum (barely) + affinis meaning “lacking
affinity” or “lacking reactivity” indicating paraffin’s unreactive nature.
 Non-polar, less dense than water, mostly chemically unreactive, except burns
vigorously.
 Insoluble in water but dissolve in non-polar solvents such as fats, oils, and
greases.
 General formula: CnH2n + 2
 Also known as PARAFFINS
 In a saturated hydrocarbon, the carbon atom arrangement may be acyclic
or cyclic.

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  The term acyclic means “not cycle”.

Major sources of alkanes:

A. Natural gas
 Consists of 80% methane , 10% ethane, and a mixture of relatively low-boiling
alkanes, chiefly propane, butane and isobutane.
B. Petroleum (or Crude oil)
 A liquid mixture of thousands of compounds, mostly hydrocarbons, formed
from the decomposition of marine plants and animals
 Some of the products derived from crude oil are gasoline, kerosene, diesel
oil, lubricating oil (mineral oil, motor oil, petrolatum), asphalt, tar

Uses of common alkanes:

Methane (Natural gas) used for cooking and heating
Ethane Used to make polythene
Propane Used in gas cylinder
Butane “camping gaz”
Octane a component of petrol

The first ten names of Straight-chain of Alkanes

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 Structural Formula
The structures of organic compounds, are generally represented in two
dimensions rather than three because of the difficulty in drawing the latter. These
two-dimensional structural representations make no attempt to portray accurately
the bond angles or molecular geometry of molecules. Their purpose is to convey
information about which atoms in a molecule are bonded to which other atoms.
Two-dimensional structural representations for organic molecules are called
structural formulas. A structural formula is a two-dimensional structural representation
that show the various atoms in a molecule are bonded to each other.
Forms of Structural
Description Example
Formula

Expanded or Full All atoms and bonds are

structural formula indicated

Each carbon is grouped

Condensed structural with hydrogens bonded
formula to it and then written as a
formula
shows the arrangement
and bonding of carbon
atoms present in an
Skeleton Structural organic molecule but
formula does not show the
hydrogen atoms
attached to the carbon
atoms
a line represents a
carbon–carbon bond
and a carbon atom is
line-angle structural
understood to be present
formula
at every point where two
lines meet and at the
ends of lines
**If the problem did not specify what type of structural formula is to use, always make
use of the CONDENSED STRUCTURAL FORMULA.

Classification of Carbon Atoms

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 The notations 1°, 2 °, 3 ° and 4 ° are often used as designations for the terms primary,
secondary, tertiary and quaternary.

Classification of Hydrogen Atom

Hydrogen take their classification from the carbon they are attached to.

Alkane Nomenclature
 Formal systematic rules exist for generating names of organic compounds
which where formulated and updated periodically by the International Union
and Pure and Applied Chemistry (IUPAC), known as IUPAC rules in 1892.
 The advantage of the IUPAC ( or systematic) naming system is that it assigns
each compound a name that not only identifies it but also enables one to
draw its structural formula.
 The basis for all IUPAC nomenclature is the set of rules used for naming
ALKANES.
 Branched-chain means that other elements besides hydrogen may be
attached to the carbon
o halogens, oxygen, nitrogen, sulfur, and even other carbons
o Any atom that takes the place of hydrogen on a parent hydrocarbon is
called a substituent or the branched part.
 A hydrocarbon substituent is called an alkyl group or sometimes called radicals

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 o use the same prefixes to indicate the number of carbons, but –ane
ending is now –yl such as: methyl, ethyl, propyl, etc…
 Continuous-chain alkanes are also frequently called straight-chain alkanes
and normal-chain alkanes.
 The unbranched alkyl groups are obtained by removing one hydrogen from
the alkane and named by replacing the –ane of the corresponding alkane
with –yl.

Some common alkyl groups.

IUPAC Rules for Naming Branched-Chain Alkanes

1. Select the longest continuous chain of carbon atoms as the parent chain or
compound.

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 2. Number the carbon atoms in the parent carbon chain starting from the end closest
to the first carbon atom that has an alkyl or other group.

3. Name the alkyl group and designate the position on the parent carbon chain by
a number.

4. When the same alkyl group branch chain occurs more than once, indicate this
repetition by a prefix (di-, tri-, tetra-, and so forth).

5. When several different alkyl groups are attached to the parent compound, list
them in alphabetical order.

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 6. Follow IUPAC punctuation rules, which include the following: (1) Separate numbers
from each other by commas. (2) Separate numbers from letters by hyphens. (3) Do
not add a hyphen or a space between the last-named substituent and the name of
the parent alkane that follows.

Additional Guideline in Alkane Nomenclature.

 When two chains of equal length compete to be parent, choose the chain
with the greatest number of substituents.

 When branching first occurs at an equal distance from either end of the parent
chain, choose the name that gives the lower number at the first point of
difference.

 For branched substituents, these are obtained by numbering the alkyl group
starting at the carbon atom attached to the parent hydrocarbon. This means
that the carbon atom attached to the parent hydrocarbon is always number
1 carbon of the substituent. The substituent name is in parenthesis, the number

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 inside the parenthesis indicates a position on the substituent, whereas the
number outside indicates the position on the parent hydrocarbon.

IUPAC Substitutive Nomenclature

 An IUPAC name may have up to 4 features: locants, prefixes, parent
compound and suffixes.

Cycloalkanes
 A saturated hydrocarbon in which carbon atoms connected to one another
in a cyclic (ring) arrangement are present.
 The simplest cycloalkane is cyclopropane, which contains a cyclic
arrangement of three carbon atoms.
 The general formula for cycloalkanes is CnH2n. Thus a given cycloalkane
contains two fewer hydrogen atoms than an alkane with the same number of
hydrogen atoms.
 Can be represented by polygons in skeletal drawings.

IUPAC Nomenclature of Cycloalkanes

IUPAC naming procedures for cycloalkanes are similar to those for alkanes. The ring
portion of a cycloalkane molecule serves as the name base, and the prefix cyclo- is
used to indicate the presence of the ring.
1. Find the parent. Count the number of carbon atoms in the ring and the number in
the largest substituent. If the number of carbon atoms in the ring is equal to or greater

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 than the number in the substituent, the compound is named as an alkyl-substituted
cycloalkane. If the number of carbon atoms in the largest substituent is greater than
the number in the ring, the compound is named as a cycloalkyl- substituted alkane.

2. Number the substituent and write the name. Numbering conventions used in
locating substituents on the ring include the following:
a. If there is just one ring substituent, it is not necessary to locate it by number.
b. When two ring substituents are present, the carbon atoms in the ring are
numbered beginning with the substituent of higher alphabetical priority and
proceeding in the direction (clockwise or counterclockwise) that gives the other
substituent the lower number.
c. When three or more ring substituents are present, ring numbering begins at the
substituent that leads to the lowest set of location numbers. When two or more
equivalent numbering sets exist, alphabetical priority among substituents determines
the set used.

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 Some additional examples:

Bicyclic Alkanes
Compounds containing two fused or bridged rings as bicycloalkanes. When naming:
use the name of the alkane corresponding to the total number of carbon atoms in
the rings as the parent name. The carbon atoms common to both rings are called
bridgeheads, and each bond, or each chain of atoms, connecting the bridgehead
atoms is called a bridge.

Use brackets to denote the number of carbon atoms in each bridge (in order of
decreasing length).

If substituents are present, number the bridged ring system beginning at one
bridgehead, proceeding first along the longest bridge to the other bridgehead, then
along the next longest bridge back to the first bridgehead. The shortest bridge is
numbered last:

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 Spirocyclic Alkane
Two rings that share a carbon atom. To name; follow all the rules for naming alkanes
with the following modifications:

1. Locate the connecting C-atom, and find the two bridges

2. Find the two bridges
3. Determine the number of carbon atoms in each bridge, excluding the connecting
C
4. Assemble the name: Spiro[bridge1.bridge2]alkane
5. The values between the brackets refer to the number of C atoms in each bridge
in ASCENDING ORDER.
6. Thus, spiro[2.4]heptane

 If it contains substituents, number the carbon atoms starting on the smaller

bridge directly connected to the connecting point (Remember: use same
rules as in naming alkanes)
 1,6-dimethylspiro[4.5]decane

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 Conformations of Alkanes
 A conformation is the specific three-dimensional arrangement of atoms in an
organic molecule at a given instant that results from rotations about carbon–
carbon single bonds.

 Staggered conformation – all C – H bonds on adjacent carbon atoms are far

apart as possible

 Eclipsed conformation – C – H on adjacent conformations are as close

together as possible

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 Conformations of Cycloalkanes

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 Conformations of Monosubstituted Cyclohexane

Physical Properties of Alkane

1. The boiling and melting points of continuous-chain alkanes and cycloalkanes
increase with an increase in carbon chain length or ring size. Branching on a carbon
chain lowers the boiling point of an alkane. Cycloalkanes have higher boiling points
than their noncyclic counterparts with the same number of carbon atoms.
2. Solubility – “Like dissolves like”. Alkanes are nonpolar, hydrophobic. They are
soluble in nonpolar solvents and insoluble in water.
3. Alkanes and cycloalkanes have densities lower than that of water.

Chemical Reactions of Alkane

1. A combustion reaction is a chemical reaction between a substance and oxygen
(usually from air) that proceeds with the evolution of heat and light.
CnH2n+2 + O2  CO2 + H2O (complete combustion)
CnH2n+2 + O2  CO + C + H2O (incomplete combustion)
2. A halogenation reaction is a chemical reaction between a substance and a
halogen in which one or more halogen atoms are incorporated into molecules of
the substance.

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 Alkane halogenation is an example of a substitution reaction. A substitution reaction
is a chemical reaction in which part of a small reacting molecule replaces an atom
or a group of atoms on a hydrocarbon or hydrocarbon derivative.
3. Another reaction of commercial importance is the nitration of alkanes to give
nitroparaffins. Such reactions usually are carried out in the vapor phase at elevated
temperatures using nitric acid ( HNO3 ) or nitrogen tetroxide ( N2O4 ) as the nitrating
agent:

4. Isomerism – The phenomenon whereby certain chemical compounds have

structures that are different although the compounds possess the same elemental
composition. Isomers – Two or more chemical substances having the same
elementary composition and molecular weight but differing in structure.
 Constitutional isomers are isomers that differ in the connectivity of atoms, that
is, in the order in which atoms are attached to each other within molecules.
There are two four-carbon alkane isomers, the compounds butane and
isobutane. Both have the molecular formula C4H10.

 Types of Constitutional Isomer

o Skeletal isomers – isomers with different carbon and hydrogen atoms
arrangement
o Positional isomers – different in the locations of the functional groups
o Functional isomers – isomers that contain different functional groups
 Conformational Isomers - differ because of rotation about single bonds (can
interconvert).

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  Configurational or Geometric Isomers – differ in the arrangement of their
atoms in space (cannot interconvert). Geometric isomers have the same
molecular formula and the same order of attachment but a different
orientation in space that cannot be overcome by rotation around a σ bond.

Other important uses of Alkanes

 Dry-cleaning agents (CCl4)
 General, local, and inhalation anesthetics (cyclopropane or CCl4)
 Topical anesthetics (chloroethane) and lubricants (petroleum jelly)
 Insecticides, pesticides
 Chlorofluorocarbons (CFCs) – carbon compounds containing fluorine and
chlorine
o Used as the dispersing gases in aerosol cans (deodorants, hair sprays,
food products)
o For making foamed plastics
o Used as refrigerants (CFCl 3, CF2Cl2, CFC11)
 Fluorinated compounds (perfluorocarbons)– used as blood extenders,
temporary substitutes for hemoglobin, the oxygen-carrying protein in blood.
o Perfluoro compounds have been used to treat premature babies,
whose lungs are often underdeveloped.
o
ELABORATE

Graded Assignment 1.3: Concept Application: Show all necessary computations

and or illustrations.
1. Discuss the intermolecular forces involved in organic compounds.
2. List all the structural formula of hexane and indicate its IUPAC name.
3. Draw the expanded formula of the following compounds:
(a) 4-Ethyl-3,4-dimethyloctane (b) 3,3-Diethyl-2,5-dimethylnonane
(c) 3-Cyclobutylhexane (d) 1,3-Dibromo-5-methylcyclohexane

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 4. Give the IUPAC name of the following compounds:

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EVALUATE

Graded Test 2: Concept Analysis/Application

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 Unit 3: Unsaturated Organic Hydrocarbons – Alkenes and
Alkynes
UNIT LEARNING OUTCOMES
 Distinguish and differentiate alkene from alkyne
 Demonstrate proficiency in naming and structure writing of unsaturated
hydrocarbons (Alkenes and Alkynes)
 Analyze and understand physical and chemical properties of unsaturated
hydrocarbons including their preparations addition reactions, isomerism
 Identify common and important sources, practical uses and their
applications in industrial setting

ENGAGE

Source: https://foodsafetyhelpline.com/artificial-ripening-fruits/
The unsaturated hydrocarbon ethene is used to stimulate the ripening process in fruit
that has been picked while still green, such as mangos.

Reflection 1.4: Identify one alkene/alkyne found at home and take a selfie.
Save it in the memory stick in PDF format with the filename:
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 EXPLORE

An unsaturated hydrocarbon is a hydrocarbon in which one or more carbon–

carbon multiple bonds (double bonds, triple bonds, or both) are present.
Unsaturated hydrocarbons will have an increased reactivity which is related to the
presence of the carbon–carbon multiple bond(s) in such compounds. Carbon–
carbon multiple bonds are the functional group for an unsaturated hydrocarbon. A
functional group is the part of an organic molecule where most of its chemical
reactions occur.

Alkenes
 Double-bonded carbon-to-carbon hydrocarbons
 Unsaturated: element of unsaturation corresponds to two fewer H-atoms than
in the saturated formula
 General formula: CnH2n
 Also known as OLEFINS (olefiant gas, meaning “oil-forming gas”) due to the
oily appearance of alkene derivatives
 Bond angle: 120O; trigonal arrangement
 Sp2 hybridized
 Bond energy of a carbon-carbon double bond is about 611 kJ/mol (~146
kcal/mol compared with the single bond of about 347 kJ/mol
 Hence, approximate energy of a pi bond is 611 kJ/mol – 347 kJ/mol = 264
kJ/mol
 Functional group: double bond
 Bond order: 2
 Double bond: composed of 1 pi bond and 1 sigma bond

Sigma Bond Framework

 Simplest member: Ethene
 Common name: Ethylene
 Alkenes are characterized by the reactions of their double bonds

 Each of the C-H σ bonds is formed by the overlap of an sp2 hybrid orbital
 C – H bond length in ethylene (1.08 Å) is slightly shorter than C – H in ethane
(1.09 Å), hence stronger bond

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 o The C = C is 1.33 Å; the C – C is 1.54 Å

Uses of Alkenes
 ETHYLENE (or ethene) – the simplest alkene CH2 = CH2
o A plant hormone used to ripen fruits
o Used in the manufacture of polyethylene
o Also converted to ethylene glycol, the major component of many
formulations of antifreeze used in automobile radiators.
 Lower alkenes are used as fuel and illuminant.
 For the manufacture of a wide variety of polymers, e.g., polyethene,
polyvinylchloride (PVC) and teflon etc.
 As a raw material for the manufacture of industrial Chemicals such as alcohols,
aldehydes, etc.
 TERPENES – unsaturated compounds; responsible for the odors of cloves and
peppermint, or perfumes from roses and lavender (volatile oils synthesized by
plants)

Nomenclature of Alkenes: IUPAC and Common Name Rules

Follows a similar process to that for alkanes
 The longest chain that contains the double bond is given the corresponding
name of the alkane modified by changing –ane ending to –ene.
 Longest continuous chain is numbered starting at the end closest to the double
bond.

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 Alkenes: IUPAC Rules
 Use the smaller of the two numbers on the double-bonded carbons to indicate
the double bond position.

 Each branch is given its alkyl name and number location on the longest chain
 Prefixes (di-, tri-, tetra-, etc) are added to the alkyl name when there is more
than one of the same branch.
 Branches are listed in alphabetically before the parent name

Multiple Double Bonds

 A compound with two double bonds is a diene; a triene has 3 double bonds;
tetraene has 4.
 Numbers are used to specify the locations of the double bonds

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 Alkenes as Substituents
 Alkenes named as substituents are called alkenyl groups.
 They can be named ethenyl, propenyl, etc or by common names.
 Common alkenyl substituents are vinyl, allyl, methylene, and phenyl (Ph)
groups.
 Phenyl group is different because it is aromatic and does not undergo the
typical reactions of alkenes.
 Most alkenes are conveniently named using IUPAC rules, but common names
are sometimes used for the simplest compounds.

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  The sp2 carbons of an alkene are called vinylic carbons. An sp3 carbon that is
adjacent to a vinylic carbon is called an allylic carbon. a hydrogen bonded
to a vinylic carbon is called a vinylic hydrogen, and a hydrogen bonded to an
allylic carbon is called an allylic hydrogen.

Cis-Trans Nomenclature
 Also called geometric isomerism
 Cis isomer – if 2 similar groups bonded to the carbons of the double bond are
on the same side of the bond
 Trans isomer – if the similar groups are on opposite sides of the bond

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  If either carbon of the double bond holds 2 identical groups, the molecule
cannot have cis and trans forms.

 Trans cycloalkenes are unstable unless the ring is large enough (at least 8 C-
atoms)
 Hence, all cycloalkenes are assumes cis unless they are specifically named
trans.
 The cis name is rarely used with cycloalkenes, except to distinguish a large
cycloalkene from its trans isomer.

E – Z Nomenclature
 Cis-trans isomers sometimes give ambiguous names.

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  E-Z system is patterned after Cahn-Ingold-Prelog convention for asymmetric
carbon atoms
 Cahn-Ingold-Prelog : ranking atoms based on ATOMIC NUMBERS: I > Br > Cl >
S>P>F>O>N>C>H
 Z = if the 2 first-priority atoms are on the same side of the double bond; German
word zusammen, “together” (cis)
 E = if the 2 first-priority atoms are on the opposite side (trans) of the double
bond; German word entgegen, “opposite”

Cyclic Isomers and Multiple Double Bonds

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 Physical Properties of Alkenes and Cycloalkenes
 The general physical properties of alkenes and cycloalkenes include
insolubility in water, solubility in nonpolar solvents, and densities lower than that
of water. Thus they have physical properties similar to those of alkanes.
 The melting point of an alkene is usually lower than that of the alkane with the
same number of carbon atoms.
 Alkenes with 2 to 4 carbon atoms are gases at room temperature.
Unsubstituted alkene with 5 to 17 carbon atoms and one double bond are
liquids, and those with still more carbon atoms are solids.

Chemical Reactions of Alkene

1. Combustion Reaction. Alkenes, like alkanes, are very flammable. The combustion
products, as with any hydrocarbon, are carbon dioxide and water.
CnH2n + O2  CO2 + H2O (complete combustion)
CnH2n+ O2  CO + C + H2O (incomplete combustion)

2. An addition reaction is a reaction in which atoms or groups of atoms are added

to each carbon atom of a carbon–carbon multiple bond in a hydrocarbon or
hydrocarbon derivative. A general equation for an alkene addition reaction is

Symmetrical addition reaction is an addition reaction in which identical atoms

(or groups of atoms) are added to each carbon of a carbon–carbon multiple
bond.
 Unsymmetrical addition reaction is an addition reaction in which different
atoms (or groups of atoms) are added to the carbon atoms of a carbon–
carbon multiple bond.
 Markovnikov’s rule states that when an unsymmetrical molecule of the form
HQ adds to an unsymmetrical alkene, the hydrogen atom from the HQ
becomes attached to the unsaturated carbon atom that already has the
most hydrogen atoms. (Remember: The rich becomes richer)
 Markovnikov’s Rule (extended): In an electrophilic addition to an alkene, the
electrophile adds in such a way as to generate the most stable intermediate.
 The most substituted carbon is the carbon of the alkene that is attached to the
most carbons.
 The less substituted carbon is the carbon of the alkene that is attached to the
fewest carbons.
a. Hydrogenation. A hydrogenation reaction is an addition reaction in which H 2 is
incorporated into molecules of an organic compound.

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 b. Halogenation. A halogenation reaction is an addition reaction in which a halogen
is incorporated into molecules of an organic compound.

c. Hydrohalogenation (Markovnikov). A hydrohalogenation reaction is an addition

reaction in which a hydrogen halide (HCl, HBr, or HI) is incorporated into molecules
of an organic compound.

Note: Hydrobromination follows anti-Markovnikov rule in the presence of hydrogen

peroxide.
d. Hydration (Markovnikov). A hydration reaction is an addition reaction in which H2O
is incorporated into molecules of an organic compound.

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 e. Addition of acids (Markovnikov). Acids other than hydrogen halides also add to
carbon-carbon bond of alkenes. Concentrated sulfuric acid, for example, reacts
with certain alkenes to form alkyl hydrogen sulfates.

Alkyl hydrogen sulfates can be converted to alcohols by heating them with

water or steam. This is called hydrolysis reaction, because a bond is cleaved by
reaction with water.

f. Addition of Alkenes to Vicinal Halohydrins. In aqueous solution chlorine and

bromine with alkenes to form vicinal halohydrins, compounds that have a halogen
and a hydroxyl group on adjacent carbons. The hydroxyl group will bond to the more
highly substituted carbon of the double bond while the halide bonds to the less high
substituted one.

g. Hydroboration-oxidation. A two-step pathway to produce alcohol. Hydroboration

is a reaction in which a boron hydride adds to a carbon-carbon bond (anti-
Markovnikov’s) forming organoborane. The organoborane is oxidized by treatment

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 with hydrogen in aqueous base and is converted to an alcohol (this is the oxidation
stage).

or

A more convenient hydroborating agent used is the borane-tetrahydrofuran

complex (H3B·THF). Another hydroborating agent used is the diborane (B2H6) with
diglyme as a solvent.

h. Epoxidation of Alkenes. Epoxidation results from the reaction of alkene with peroxy
acids. One of the resulting product is the epoxide Epoxides is a three-membered rings
that contain oxygen.

Substitutive IUPC nomenclature names epoxides as epoxy derivatives of

alkanes. The prefix epoxy- always immediately precedes the alkane ending; it is not
listed in alphabetical order like other substituents.

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 i. Ozonalysis of Alkene. Ozone is a powerful electrophile and undergoes a remarkable
reaction with alkenes in which both the 𝛔 and 𝛑 components of the carbon-carbon
double bond are cleaved to give a product referred to as ozonide. Ozonides
undergo hydrolysis in water, giving carbonyl compounds.

The two-stage reaction o ozonolysis is represented by a general equation:

The carbonyl group may either be an aldehyde or a ketone.

3. Reaction of alkenes with alkenes: Polymerization. A polymer is a large molecule

formed by the repetitive bonding together of many smaller molecules. The smaller
repeating units of a polymer are called monomers. A monomer is the small molecule
that is the structural repeating unit in a polymer. The process by which a polymer is
made is called polymerization. A polymerization reaction is a chemical reaction in
which the repetitious combining of many small molecules (monomers) produces a
very large molecule (the polymer).

Many substituted alkenes undergo polymerization similar to that of ethene when they
are treated with the proper catalyst. The table shows some alkene polymers and their
uses.

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 4. Oxidation of Alkenes
a. Alkenes can easily be oxidized by potassium permanganate and other oxidizing
agents. At cold temperatures with low concentrations of oxidizing reagents, alkenes
tend to form glycols. This is also called Baeyer’s Test, a test used to determine

b. When more concentrated solutions of potassium permanganate and higher

temperatures are employed, the glycol is further oxidized, leading to the formation
of a mixture of ketones and carboxylic acids.

EXPLAIN

Alkynes
 Hydrocarbons that contain carbon-carbon triple bonds
 Known as the acetylene group
 Acetylene, the simplest alkyne is produced industrially from methane and
steam at high temperature
 Alkynes contain a triple bond.
 General formula is CnH2n-2.
 Two elements of unsaturation for each triple bond.

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  Some reactions are like alkenes: addition and oxidation.
 Some reactions are specific to alkynes.

Naming of Alkynes
A. IUPAC Naming
 General hydrocarbon rules apply with “-yne” as a suffix indicating an alkyne
 Find the longest chain containing the triple bond.
 parent chain = longest continuous carbon chain that contains the triple bond.
 Number the chain, starting at the carbon atom closest to the triple bond.
 Give branches or other substituents a number to locate their position. prefix
locant for the triple bond, etc.
 Compounds containing both double and triple bonds are called enynes (not
ynenes). Numbering of an enyne chain starts from the end nearer the first
multiple bond, whether double or triple. When there is a choice in numbering,
double bonds receive lower numbers than triple bonds.
 Cycloalkyne cyclic alkyne is named by prefixing cyclo to the open chain
alkyne having the same number of carbon as a ring.

 Alkynyl substituents are also possible, here are some common alkynyl
substituents

B. Common Names. Name the alkyl group and attached it with the term acetylene,
“alkylacetylene”.
CH≡CH acetylene
CH≡CCH3 methylacetylene
CH3C≡CCH3 Dimethylacetylene (IUPAC: 2-butyne or But-2-yne)
PhC≡CH Phenylacetylene (Ph means aromatic ring)
CH3CH2C≡CCH3 ethylmethylacetylene (IUPAC: 2-Pentyne or Pent-2-yne)

Physical Properties of Alkyne

 A bit similar to those of alkenes and alkanes.
 Boiling points increase with molecular mass.
 Low molecular weight alkynes (2-4 carbon atoms) are gases at room
temperature.
 Alkynes with 5-8 carbon atoms are liquids and those with still more carbon
atoms are solids.

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  Nonpolar, insoluble in water. Soluble in most organic solvents.
 Have boiling points that increase with molecular mass.
 Less dense than water.

Chemical Reactions of Alkyne

The triple-bond functional group of alkynes behaves chemically quite similarly to the
double-bond functional group of alkenes. Thus there are many parallels between
alkene chemistry and alkyne chemistry. However, the triple bond makes alkynes
more reactive than the alkenes and alkanes.
1. Addition Reactions
a. Hydrogenation Reaction

Partial hydrogenation of alkyne (conversion of alkynes to alkenes by hydrogenation.

If the catalyst that will be used is the Lindlar catalyst, a palladium on calcium
carbonate combination to which lead acetate and quinoline have been added,
will yield to a cis (or Z) alkene. And if the catalyst is by a Group 1 metal (Li, Na or K) in
liquid ammonia, it will yield to a trans (or E) alkene.

b. Addition of Hydrogen Halides. Follow the Markovnikov’s Rule.

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 c. Hydration of Alkyne. Hydration of an alkyne is expected to yield an alcohol. The
kind of alcohol one in which the hydroxyl group is a substituent on a carbon-carbon
double bond which is called an enol. An important property of enols is their rapid
isomerization to aldehydes or ketones.

d. Addition of Halogens. Alkynes react with chlorine and bromine to yield

tetrahaloalkanes.

e. Ozonolysis of Alkynes. Carboxylic acids are produced when alkynes are subjected
to ozonolysis.

2. Terminal alkynes are weakly acidic. When a terminal alkyne is treated with a strong
base, such as sodium amide, Na+ -NH2, the terminal hydrogen is removed and the
corresponding acetylide anion is formed.

3. Alkyne alkylation. An alkylation reaction is when a new alkyl group has become
attached to the starting alkyne. Any terminal alkyne can be converted into its

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 corresponding anion and then allowed to react with an alkyl halide to give an
internal alkyne product. The alkylation reaction can only use primary alkyl bromides
and alkyl iodides because acetylide ions are sufficiently strong bases to cause
elimination instead of substitution when they react with secondary and tertiary alkyl
halides.

ELABORATE

Organohalides
 Compounds that contain one or more halogen atoms.
 Halogen-substituted organic compounds are widespread in nature such as
chloromethane which is released in large amounts by ocean kelp, as well as
by forest fires and volcanoes.
 Halogen-containing compounds also have a vast array of industrial
applications, including their use as solvents, inhaled anesthetics in medicine,
refrigerants, pesticides and food additives.
 The halogen might be bonded to an alkynyl group (C=C-X), a vinylic group
(C=C-X), an aromatic ring (Ar-X), or an alkyl group.
Note: It will primarily focus on the alkyl halides compounds with a halogen atom
bonded to a saturated carbon atom.

Naming of Organohalides
A. IUPAC Naming
Halogen-substituted alkanes are named systematically as haloalkanes, treating
the halogen as a substituent on a parent alkane chain.
 Find the longest chain, and name it as the parent. If a double or triple bond is
present, the parent chain must contain it.
 Number the carbons of the parent chain beginning at the end nearer the first
substituent, whether alkyl or halo. Assign each substituent a number according
to its position on the chain. If different halogens are present, number each one
and list them in alphabetical order when writing the name.
 If the parent chain can be properly numbered from either end, begin at the
end nearer the substituent that has alphabetical precedence.

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 B. Common Naming. Simple alkyl halides are also named by identifying first the
alkyl group and then the halogen.

Common Name:
IUPAC Name:

Structure of Alkyl Halides

 C-X bond is longer as you go down periodic table
 C-X bond is weaker as you go down periodic table
 C-X bond is polarized with slight positive charge on carbon and slight charge
on halogen

Classification of Organohalides
The halogen atom may be primary (1º), secondary (2º) or tertiary (3º) depending on
the carbon atom to which it is attached.

Primary 1° Secondary 2° Tertiary 3°

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 A primary halogenoalkane has the halogen bonded to a carbon, which is itself
only attached to one other carbon atom. A secondary halogenoalkane has the
halogen bonded to a carbon that is itself attached to two other carbon atoms. In
tertiary halogenoalkanes, the halogen is bonded to a carbon that is itself attached
to three other carbon atoms.

Properties of Organohalides
 Halogenated alkane boiling points are generally higher than those of the
corresponding alkane.
 Some halogenated alkanes have densities that are greater than that of water,
a situation not common for organic compounds.

Chemical Reactions of Organohalides

1. Nucleophilic substitution. Halogenoalkanes are attacked by nucleophilic reagents
(reagents seeking a positive charge) and undergo substitution of the halide ion by
the nucleophile. The general reaction scheme is as follows:
R-X + Nu-  R-Nu + X-
where R is an alkyl chain, X is the halide ion and Nu the nucleophile.
a. Reaction with Hydroxide ions. Halogenoalkanes undergo nucleophilic substitution
on warming with dilute alkali, making alcohols:
R-X + NaOH  ROH + NaX
haloalkane sodium hydroxide alcohol sodium halide
CH3Cl + NaOH  CH3OH + NaCl
chloromethane sodium hydroxide methanol sodium chloride
b. Reaction with water There is only a slow reaction between a primary
halogenoalkane and water even if they are heated. The halogen atom is replaced
by -OH.
R-X + HOH  ROH + HX
haloalkane water alcohol Hydrohalic acid
CH3Cl + HOH  CH3OH + HCl
chloromethane water methanol Hydrochloric acid
c. Reaction with cyanide ions. The cyanide ion, CN- is a good nucleophile and reacts
with haloalkanes producing nitriles.
R-X + KCN  RCN + KX
haloalkane potassium cynanide alkanenitrile potassium halide
CH3CH2Cl + KCN  CH3CH2CN + KCl
chloroethane potassium cyanide propanenitrile potassium halide
d. Reaction with ammonia. The halogenoalkane is heated with a concentrated
solution of ammonia in ethanol under reflux producing amines.

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 alcohol
R-X + NH3  RNH3+X-
reflux
haloalkane ammonia alkylammonium salt
RNH3+X + NH3  RNH2 + NH4+X-
alkylammonium salt ammonia 1° amine ammonium halide
alcohol
CH3CH2Br + NH3  CH3CH2Br NH3+Br-
reflux
bromoalkane ammonia ethylammonium bromide
CH3CH2Br NH3+Br- + NH3  CH3CH2NH2 + NH4+Br-
ethylammonium salt ammonia ethanamine ammonium bromide

2. Formation of organometallic reagents. Organometallic Compounds are chemical

compounds which contain at least one bond between a metallic element and a
carbon atom belonging to an organic molecule.
a. Grignard Reagent. Alkyl halides, RX, react with magnesium metal in ether or
tetrahydrofuran (THF) solvent to yield alkylmagnesium halides, RMgX. The products,
called Grignard reagents (RMgX) after their discoverer, Victor Grignard.
Mg
R-X  RMgX
ether/THF
haloalkane alkylmagnesium halide
Mg
CH3CH2Br  CH3CH2MgBr
ether/THF
bromoethane ethylmagnesium bromide
b. Gilman reagent. Alkyl halides also react with lithium metal to form organolithium
reagents, RLi. In the presence of CuI, these form diorganocoppers, or Gilman
reagents (LiR2Cu). Gilman reagents react with organohalides to yield coupled
hydrocarbon products.
2Li
R-X  RLi + LiX
pentane
haloalkane alkyllithium lithium halide
2RLi + CuI  (R-Cu-R)-Li+ + LiI
In ether
alkyllithium cuprous iodide lithium dialkylcopper lithium iodide
R2CuLi + R’X  R-R’ + RCu + LiX
In ether
lithium dialkylcopper haloalkane alkane alkylcopper lithium halide

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 2Li
CH3CH2Br  CH3CH2Li + LiBr
pentane
bromoethane ethyllithium lithium bromide

2 CH3CH2Li + CuI  (CH3CH2-Cu- CH3CH2)-Li+ + LiI

In ether
ethyllithium cuprous iodide lithium diethylcopper lithium iodide
(CH3CH2)2CuLi + CH3Br  CH3CH2CH3 + CH3CH2Cu + LiBr
In ether
lithium diethylcopper bromomethane propane ethylcopper

Industrial Uses of Some Halogenated Hydrocarbons

Graded Assignment 1.4: Concept Application: Show all necessary computations

and or illustrations.
(1) Write a complete chemical equation showing reactants, products, and catalysts
needed (if any) for the following reaction and (2) Draw and name the organic
compound found in every reaction.
(a) Complete hydrogenation of 2-Methylhexa-1,5-diene
(b) Complete halogenation (Br2) of 3-Ethyl-2,2-dimethylhept-3-ene
(c) Reaction of (4E)-2,4-Dimethylhexa-1,4-diene with a mole of water
(d) Reaction of cis-3,3-Dimethyl-4-propylocta-1,5-diene with two mole of HBr
(e) Reaction of trans-1-Bromo-3-chlorocyclopentane with potassium hydroxide
(f) Formation of Gilman reagent using isopropyl bromide
(g) Ozonolysis of 3,3-Dimethyloct-4-yne
(h) Complete halogenation (Cl 2) of 3-Ethyl-5-methyl-1,6,8-decatriyne
(i) Partial hydrogenation using Lindlar’s Catalyst 2,2,5,5-Tetramethylhex-3-yne
(j) Reaction of 3,4-Dimethylcyclodecyne with sodium amide

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 EVALUATE

Graded Test 3: Concept Analysis/Application

Save it in the memory stick in PDF format with the filename:
Graded Test1 FAMILY NAME, GIVEN NAME

The learnings from Module 1 Units 1-4 is the coverage of your Prelim Examination. This
is an Evaluative Assessment.
Save it in the memory stick in PDF format with the filename:
Prelim Exam FAMILY NAME, GIVEN NAME

Main Reference/s
McMurry, John (2016). Organic Chemistry. 9th ed. Australia: Brooks/Cole/Cengage
Learning, c2012

Books
Arora, Amit. (2009) Advanced Practical Organic Chemistry. New Delhi, India:
Discovery Publishing House.
Bettelheim, Frederick A., W. H. Brown, M. Campbell, S. Farrell (2010). Introduction to
Organic and Biochemistry 7th Ed. Brooks/Cole, Cengage Learning.
Bruice, Paula Yurkanis. (2010). Essential Organic Chemistry 2nd Ed. Boston Prentice
Hall.
Brown, William H. (2011) Introduction To Organic Chemistry 4th Ed. Hoboken, New
Jersey. John Wiley and Sons.
Carey, Francis A. (2000). Organic Chemistry 4th Ed. McGraw Hill.
Smith, Janice Gorzynski. (2009). Organic Chemistry. 3rd ed. New York:
Stoker, H. (2010). General, Organic and Biological Chemistry. 5th ed. Brooks/Cole,
Cengage Learning.
Wade, Jr. L. G. (2013). Organic chemistry. 8th ed. Boston, Massachusetts: Pearson.

Electronic References:
https://www.cliffsnotes.com/study-guides/chemistry/organic-chemistry-i
https://studfile.net/preview/409584/
https://www.ibchem.com/IB16
https://www.chemguide.co.uk
http://www.docbrown.info/page13/page13a.htm
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/

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