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SCHOOL OF PSYCHOLOGY AND HUMAN SERVICES

INSTRUCTIONAL MODULE IN
NATSCI 301: Organic Chemistry

PRELIMINARIES
I. Lesson Number 1
II. Lesson Title Introduction to Organic Chemistry
III. Brief Introduction This lesson introduces the students to organic chemistry, it’s
of the Lesson history, and the basic knowledge on the course.
IV. Lesson Objectives ● Define organic chemistry.
● Identify organic molecules as alkanes, alkenes, alkynes,
alcohols, or carboxylic acids.

LESSON PROPER
I. Getting Started
1. Do you have any ideas on Organic Chemistry?
2. How do you think organic chemistry can be applied in real life?
II. Discussion

History

Jöns Jacob Berzelius, a physician by trade, first coined the term “organic chemistry” in 1806
for the study of compounds derived from biological sources. Up through the early 19th century,
naturalists and scientists observed critical differences between compounds that were derived from
living things and those that were not.

Chemists of the period noted that there seemed to be an essential yet inexplicable difference
between the properties of the two different types of compounds. The vital force theory, sometimes
called “vitalism” (vital means “life force”), was therefore proposed, and widely accepted, as a way
to explain these differences, that a “vital force” existed within organic material but did not exist in
any inorganic materials.

Synthesis of Urea

Friedrich Wöhler is widely regarded as a pioneer in organic chemistry as a result of his

synthesizing of the biological compound urea (a component of urine in many animals) utilizing
what is now called “the Wöhler synthesis.”

Wöhler mixed silver or lead cyanate with ammonium nitrate; this was supposed to yield
ammonium cyanate as a result of an exchange reaction, according to Berzelius’s dualism theory.
Wöhler, however, discovered that the end product of this reaction is not ammonium cyanate
(NH4OCN), an inorganic salt, but urea ((NH2)2CO), a biological compound. (Furthermore,
heating ammonium cyanate turns it into urea.) Faced with this
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result, Berzelius had to concede that (NH2)2CO and NH4OCN were isomers. Until this discovery
in the year 1828, it was widely believed by chemists that organic substances could only be formed
under the influence of the “vital force” in the bodies of animals and plants. Wöhler’s synthesis
dramatically proved that view to be false.

Urea synthesis was a critical discovery for biochemists because it showed that a compound
known to be produced in nature only by biological organisms could be produced in a laboratory
under controlled conditions from inanimate matter. This “in vitro” synthesis of organic matter
disproved the common theory (vitalism) about the vis vitalis, a transcendent “life force” needed
for producing organic compounds.

Organic vs inorganic chemistry

Although originally defined as the chemistry of biological molecules, organic chemistry has since
been redefined to refer specifically to carbon compounds — even those with non-biological origin.
Some carbon molecules are not considered organic, with carbon dioxide being the most well
known and most common inorganic carbon compound, but such molecules are the exception and
not the rule.

Organic chemistry focuses on carbon and following movement of the electrons in carbon chains
and rings, and also how electrons are shared with other carbon atoms and heteroatoms. Organic
chemistry is primarily concerned with the properties of covalent bonds and non-metallic elements,
though ions and metals do play critical roles in some reactions.

The applications of organic chemistry are myriad, and include all sorts of plastics, dyes,
flavorings, scents, detergents, explosives, fuels and many, many other products. Read the
ingredient list for almost any kind of food that you eat, or even your shampoo bottle, and you will
see the handiwork of organic chemists listed there.

Major advances in the field of organic chemistry

Of course a chemistry text should at least mention Antoine Laurent Lavoisier. The French
chemist is often called the “Father of Modern Chemistry” and his place is first in any
pantheon of great chemistry figures. Your general chemistry textbook should contain information
on the specific work and discoveries of Lavoisier — they will not be repeated here because his
discoveries did not relate directly to organic chemistry in particular. Berzelius and Wöhler are
discussed above, and their work was foundational to the specific field of organic chemistry. After
those two, three more scientists are famed for independently proposing the elements of structural
theory. Those chemists were August Kekulé, Archibald Couper, and Alexander
Butlerov.

Kekulé was a German, an architect by training, and he was perhaps the first to propose that
isomerism was due to carbon’s proclivity towards forming four bonds. Its ability to bond with up
to four other atoms made it ideal for forming long chains of atoms in a single molecule, and also
made it possible for the same number of atoms to be connected in an
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enormous variety of ways. Couper, a Scot, and Butlerov, a Russian, came to many of the same
conclusions at the same time or just a short time after.

Through the nineteenth century and into the twentieth, experimental results brought to light much
new knowledge about atoms, molecules, and molecular bonding. In 1916 it was Gilbert Lewis of
U.C. Berkeley who described covalent bonding largely as we know it today (electron-sharing).
Nobel laureate Linus Pauling further developed Lewis’ concepts by proposing resonance while he
was at the California Institute of Technology. At about the same time, Sir Robert Robinson of
Oxford University focused primarily on the electrons of atoms as the engines of molecular change.
Sir Christopher Ingold of University College, London, organized what was known of organic
chemical reactions by arranging them in schemes we now know as mechanisms, in order to better
understand the sequence of changes in a synthesis or reaction.

The field of organic chemistry is probably the most active and important field of chemistry at the
moment, due to its extreme applicability to both biochemistry (especially in the pharmaceutical
industry) and petrochemistry (especially in the energy industry). Organic chemistry has a
relatively recent history, but it will have an enormously important future, affecting the lives of
everyone around the world for many, many years to come.

Organic Chemistry

Organic chemistry is the study of the chemistry of carbon compounds. Carbon is singled out
because it has a chemical diversity unrivaled by any other chemical element. Its diversity is based
on the following:

● Carbon atoms bond reasonably strongly with other carbon atoms.

● Carbon atoms bond reasonably strongly with atoms of other elements.
● Carbon atoms make a large number of covalent bonds (four).

Curiously, elemental carbon is not particularly abundant. It does not even appear in the list of the
most common elements in Earth’s crust. Nevertheless, all living things consist of organic
compounds.

Most organic chemicals are covalent compounds, which is why we introduce organic chemistry
here. By convention, compounds containing carbonate ions and bicarbonate ions, as well as carbon
dioxide and carbon monoxide, are not considered part of organic chemistry, even though they
contain carbon.

The simplest organic compounds are the hydrocarbons, compounds composed of carbon and
hydrogen atoms only. Some hydrocarbons have only single bonds and appear as a chain (which
can be a straight chain or can have branches) of carbon atoms also bonded to hydrogen atoms.
These hydrocarbons are called alkanes (saturated hydrocarbons). Each alkane has a characteristic,
systematic name depending on the number of carbon atoms in the molecule. These names consist
of a stem that indicates the number of carbon atoms in the chain plus the ending –ane. The stem
meth– means one carbon atom, so methane is an alkane with one carbon atom. Similarly, the stem
eth– means two carbon atoms; ethane is an alkane with two carbon atoms. Continuing, the stem
prop– means three carbon atoms, so propane is an alkane with three carbon atoms.
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Figure 1.1. “Formulas and Molecular Models of the Three Simplest Alkanes”

The three smallest alkanes are methane, ethane, and

propane.

Some hydrocarbons have one or more carbon–carbon double bonds (denoted C=C). These
hydrocarbons are called alkenes. Note that the names of alkenes have the same stem as the
alkane with the same number of carbon atoms in its chain but have the ending –ene. Thus, ethene
is an alkene with two carbon atoms per molecule, and propene is a compound with three carbon
atoms and one double bond.

Figure 1.2. Formulas and Molecular Models of the Two Simplest Alkenes

Ethene is commonly called ethylene, while propene is commonly called propylene.

Alkynes are hydrocarbons with a carbon–carbon triple bond (denoted C≡C) as part of their carbon
skeleton (see section 3.2. for more information). The names for alkynes have the same stems as for
alkanes but with the ending –yne.
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Figure 1.3. Formulas and Molecular Models of the Two Simplest Alkynes

Ethyne is more commonly called acetylene.

To your health: saturated and unsaturated fats

Hydrocarbons are not the only compounds that can have carbon–carbon double bonds. A group of
compounds called fats can have them as well, and their presence or absence in the human diet is
becoming increasingly correlated with health issues.

Fats are combinations of long-chain organic compounds (fatty acids) and glycerol (C3H8O3). The
long carbon chains can have either all single bonds, in which case the fat is classified as saturated,
or one or more double bonds, in which case it is a monounsaturated or a polyunsaturated fat,
respectively. Saturated fats are typically solids at room temperature; beef fat (tallow) is one
example. Mono- or polyunsaturated fats are likely to be liquids at room temperature and are often
called oils. Olive oil, flaxseed oil, and many fish oils are mono- or polyunsaturated fats.

Some studies have linked higher amounts of saturated fats in people’s diets with a greater
likelihood of developing heart disease, high cholesterol, and other diet-related diseases. In
contrast, increases in unsaturated fats (either mono- or polyunsaturated) have been linked to a
lower incidence of certain diseases. Thus, there have been recommendations by government
bodies and health associations to decrease the proportion of saturated fat and increase the
proportion of unsaturated fat in the diet. Most of these organizations also recommend decreasing
the total amount of fat in the diet. A difference as simple as the difference between a single and
double carbon–carbon bond can have a significant impact on health.

The carbon–carbon double and triple bonds are examples of functional groups in organic
chemistry. A functional group is a specific structural arrangement of atoms or bonds that imparts a
characteristic chemical reactivity to a molecule. Alkanes have no functional group, and they are
mostly inert (unreactive). A carbon–carbon double bond is considered a functional group because
carbon–carbon double bonds chemically react in specific ways that differ from reactions of
alkanes (for example, under certain circumstances, alkenes react with water); a carbon–carbon
triple bond also undergoes certain specific chemical reactions. In the remainder of this section, we
introduce two other common functional groups.

If an OH group (also called a hydroxyl group) is substituted for a hydrogen atom in a hydrocarbon
molecule, the compound is an alcohol. Alcohols are named using the parent hydrocarbon name but
with the final –e dropped and the suffix –ol attached. The two simplest alcohols are methanol and
ethanol (see Figure 1.4.).
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Figure 1.4. The two simplest organic alcohol compounds

Alcohols have an OH functional group in the molecule. Ethanol (also called ethyl alcohol) is the
alcohol in alcoholic beverages. Other alcohols include methanol (or methyl alcohol), which is used
as a solvent and a cleaner, and 2-propanol (also called isopropyl alcohol or rubbing alcohol),
which is used as a medicinal disinfectant. Neither methanol nor isopropyl alcohol should be
ingested, as they are toxic even in small quantities. Cholesterol is an example of a more complex
alcohol.

Another important family of organic compounds has a carboxyl group, in which a carbon atom is
double-bonded to an oxygen atom and to an OH group. Compounds with a carboxyl functional
group are called carboxylic acids, and their names end in –oi acid. The two simplest carboxylic
acids are shown in Figure 1.5. They are perhaps best known by the common names formic acid
(found in the stingers of ants) and acetic acid (found in vinegar). The carboxyl group is sometimes
written in molecules as COOH.

Figure 1.5. The two smallest organic acids

Many organic compounds are considerably more complex than the examples described here. Many
compounds contain more than one functional group. The formal names can also be quite complex.

III. Application (Performance Task-40%)

Identify the type of hydrocarbon in each structure.
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1.

2.

3.

4.

IV. Assessment(Written Works-20%)

1. What is organic chemistry?

2. What is a functional group? Give at least two examples of functional groups

V. Reflection
1. From what you learned in this lesson, how can you apply organic chemistry in your daily
life?

VI. References
Authored by: Saylor Academy. License: CC BY-NC-SA: Attribution-NonCommercial-ShareAlike

Prepared by:

ASHER JETHRO E. VELEÑA, M.D.

Instructor

Reviewed by: Approved by:

ARGELOU P. PADERES, MAPsy.,RPm JESS JAY M. SAJISE, DBA
Program Head, BS Psychology
Vice President of Academic Affairs External