Scientist Name: ________________________________________________ Block: ________
Organic Chemistry
What Is Organic Chemistry? Highlight important information!
Words are funny things. A word that means one thing to one person might mean something completely different to another person. In
the United States the word footballrefers to a game played with an oval-shaped ball that players pass with their hands or hold with
their hands while they run with it. In England football refers to a game played with a round ball that players kick with their feet. (In
the United States people call this game soccer.)
The word organic is another word that means different things to different people. To many people organic means “natural.” For
example, gardeners sometimes talk about using organic fertilizer. What they mean is that they’re putting something natural like
compost or manure on their plants instead of human-made, or synthetic, fertilizers.
Organic means something completely different to chemists. In chemistry organic means “carbon-based.” To a chemist, an organic
compound is any compound that contains carbon. That is, an organic compound is any compound whose molecules contain carbon
atoms. All living things are made of compounds containing mostly carbon, so lots of things that are “organic” to a gardener are also
“organic” to a chemist.
Of course, there are many carbon compounds that are human-made, or synthetic. To chemists, these are organic compounds too.
Plastics are organic, and so are most synthetic wonder drugs, as far as chemists are concerned. They are organic because they are
carbon-based. Chemists would even say most of the synthetic fertilizers, the ones that “organic” gardeners don’t use, are organic too.
This is because synthetic fertilizers are made of molecules that are made of mostly carbon atoms.
In fact, most chemists laugh a little when they see the word organic on food packages in the grocery store. All food is made of carbonbased molecules, and so are most food additives, whether they’re natural or synthetic. So to a chemist, all food is “organic.”
How in the world did this happen? Why do chemists use the word organic so differently from everyone else? Living things are
sometimes called organisms. A long time ago the word organic was used to describe anything that came from an organism—anything
that came from a living thing. Chemists who worked with substances found in living things were called organic chemists.
Just about every substance you pull out of a plant or animal is made of mostly carbon atoms—except water, of course. In time, organic
chemists learned how to turn plant and animal compounds into all kinds of other things. Chemists used plant and animal compounds to
make new compounds that are not found in nature. Even though these substances weren’t natural, they had something in common with
plant and animal matter: their molecules were still made of carbon atoms. After all, when chemists turn one substance into another, all
they are doing is taking apart its molecules and putting the atoms back together in different ways. Carbon in, carbon out.
Organic chemists also figured out how to synthesize a lot of natural plant and animal compounds from nonliving materials. In 1827 a
chemist named Friedrich Wöhler was playing with some mineral salts. He accidentally made urea, a compound found in urine. He
wrote to a friend saying, “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.”
There was more to come. Petroleum is mostly carbon. Scientists learned how to make all kinds of other plant and animal compounds
from it. For example, they made vitamins and sugars from petroleum. Organic chemists branched out even further. They started
making new carbon-based materials from nonliving things. They made everything from gasoline to plastics out of petroleum. With all
this branching out, organic chemistry grew to be the chemistry of all carbon compounds, whether or not they came from living things.
Petroleum, gasoline, and plastics are all carbon-based, and so they came to be considered organic by chemists.
So here we are today, with the word organic meaning “carbon-based” to chemists and meaning “natural” to everyone else. There’s a
real reason for chemists to have their own meaning for the word organic, and it has to do with a concern in chemistry for how
substances behave. A substance behaves or reacts the way it does because of the atoms its molecules are made of, and how they are
put together. This means carbon-based compounds should behave differently from compounds based on other elements. Therefore, it
is useful for chemists to group carbon-based compounds together because they are similar in a chemically interesting way.
But from the perspective of the way compounds react or behave, there is no such reason for chemists to separate natural compounds
from synthetic compounds. If two molecules are made of the exact same atoms put together in the exact same way, they are going to
behave in the exact same way, even if one molecule was made in nature and the other was made by a scientist in a laboratory.
Moreover, there aren’t really any properties that all natural materials have that synthetic materials don’t have, and vice versa. Both
natural and synthetic substances can be deadly; and both natural and synthetic materials can be safe to eat.
So when we talk about “organic chemists,” we’re not talking about chemists who only use all-natural substances. We’re talking about
chemists who make and study compounds that are made of carbon, whether the compounds are natural or synthetic.
Part 2: Questions! Answer these in your notebook.
1. What does the term "organic" mean to chemists?
2. What is an organic compound?
3. How is the term "organic" used among farmers and food stores today?
4. Why are carbon-based compounds lumped together as a separate subject within the study of chemistry?
5. Is carbon a metal or a nonmetal?
6. Carbon's atomic number is six. What does that tell us about any carbon atom?
7. What is carbon's electron shell configuration?
8. How many valence electrons does carbon have?
9. Will carbon as an atom interact with other atoms to form ionic or covalent bonds?
10. In order to fill its outer shell, how many bonds will carbon make?
11. What are hydrocarbons?
12. Are hydrocarbons organic or inorganic molecules? Why?
13. Why can carbon form so many different types of compounds?
PART 2:
Did you know that organic chemicals make up all the life forms we know of? Organic chemistry, defined by the carbon-hydrogen
bond, is at the foundation of life. Because of the unique properties of the carbon atom, it can bond with other atoms in many different
ways, resulting in millions of different organic molecules.
To understand life as we know it, we must first understand a little bit of organic chemistry. Organic molecules contain both carbon and
hydrogen. Though many organic chemicals also contain other elements, it is the carbon-hydrogen bond that defines them as organic.
Organic chemistry defines life. Just as there are millions of different types of living organisms on this planet, there are millions of
different organic molecules, each with different chemical and physical properties. There are organic chemicals that make up your hair,
your skin, your fingernails, and so on. The diversity of organic chemicals is due to the versatility of the carbonatom. Why is carbon
such a special element? Let's look at its chemistry in a little more detail.
The uniqueness of carbon
Carbon (C) appears in the second row of the periodic table and has four bonding electrons in itsvalence shell (see our Periodic
Table module for more information). Similar to other non-metals, carbon needs eight electrons to satisfy its valence shell. Carbon
therefore forms four bonds with other atoms (each bond consisting of one of carbon's electrons and one of the bonding atom's
electrons). Every valence electron participates in bonding; thus, a carbon atom's bonds will be distributed evenly over the atom's
surface. These bonds form a tetrahedron (a pyramid with a spike at the top), as illustrated below:
Carbon forms 4 bonds
Organic chemicals get their diversity from the many different ways carbon can bond to otheratoms. The simplest organic chemicals,
called hydrocarbons, contain only carbon and hydrogen atoms; the simplest hydrocarbon (called methane) contains a single carbon
atom bonded to four hydrogen atoms:
Methane - a carbonatom bonded to 4hydrogenatoms
But carbon can bond to other carbon atoms in addition to hydrogen, as illustrated in themolecule ethane below:
Ethane - a carbon-carbon bond
In fact, the uniqueness of carbon comes from the fact that it can bond to itself in many different ways. Carbon atoms can form long
chains:
Hexane - a 6-carbon chain
branched chains:
Isohexane - a branched-carbon chain
rings:
Cyclohexane - a ringed hydrocarbon
There appears to be almost no limit to the number of different structures that carbon can form. To add to the complexity of organic
chemistry, neighboring carbon atoms can form double and triple bonds in addition to single carbon-carbon bonds:
Single bonding
Double bonding
Triple bonding
Keep in mind that each carbon atom forms four bonds. As the number of bonds between any two carbon atoms increases, the number
of hydrogen atoms in the molecule decreases (as can be seen in the figures above).
Comprehension Checkpoint
__________ can form long chains, branched chains, and rings.

Carbon

Hydrogen
Check answer
Simple hydrocarbons
The simplest hydrocarbons are those that contain only carbon and hydrogen. These simple hydrocarbons come in three varieties
depending on the type of carbon-carbon bonds that occur in the molecule.
Alkanes
Alkanes are the first class of simple hydrocarbons and contain only carbon-carbon single bonds. The alkanes are named by combining
a prefix that describes the number of carbon atoms in themolecule with the root ending "ane". The names and prefixes for the first ten
alkanes are given in the following table.
Carbon
Atoms
Prefix
Alkane
Name
Chemical
Formula
Structural
Formula
1
Meth
Methane
CH 4
CH4
2
Eth
Ethane
C2H6
CH3CH3
3
Prop
Propane
C3H8
CH3CH2CH3
4
But
Butane
C4H10
CH3CH2CH2CH3
5
Pent
Pentane
C5H12
CH3CH2CH2CH2CH3
6
Hex
Hexane
C6H14
...
7
Hept
Heptane
C7H16
8
Oct
Octane
C8H18
9
Non
Nonane
C9H20
10
Dec
Decane
C10H22
The chemical formula for any alkane is given by the expression CnH2n+2. The structural formula, shown for the first five alkanes in the
table, shows each carbon atom and the elements that are attached to it. This structural formula is important when we begin to discuss
more complexhydrocarbons. The simple alkanes share many properties in common. All enter into combustionreactions with oxygen to
produce carbon dioxide and water vapor. In other words, many alkanes are flammable. This makes them good fuels. For example,
methane is the principle component of natural gas, and butane is common lighter fluid.
CH4 + 2O2
CO2 + 2H2O
The combustion of methane
Alkenes
The second class of simple hydrocarbons, the alkenes, consists of molecules that contain at least one double-bonded carbon pair.
Alkenes follow the same naming convention used foralkanes. A prefix (to describe the number of carbon atoms) is combined with the
ending "ene" to denote an alkene. Ethene, for example is the two-carbon molecule that contains one double bond. The chemical
formula for the simple alkenes follows the expression CnH2n. Because one of the carbon pairs is double bonded, simple alkenes have
two fewer hydrogen atoms than alkanes.
Ethene
Alkynes
Alkynes are the third class of simple hydrocarbons and are molecules that contain at least one triple-bonded carbon pair. Like
the alkanes and alkenes, alkynes are named by combining a prefix with the ending "yne" to denote the triple bond. The chemical
formula for the simple alkynes follows the expression CnH2n-2.
Ethyne
Comprehension Checkpoint
The simplest of hydrocarbons are called

alkanes.

alkynes.
Check answer
Isomers
Because carbon can bond in so many different ways, a single molecule can have different bonding configurations. Consider the two
molecules illustrated here:
C6H14
CH3CH2CH2CH2CH2CH3
C6H14
CH
3
I
CH3
CH2
CH
CH2
CH3
Both molecules have identical chemical formulas (shown in the left column); however, their structural formulas (and thus some
chemical properties) are different. These two molecules are called isomers. Isomers are molecules that have the same chemical
formula but different structural formulas.
Comprehension Checkpoint
When molecules have the same number and type of atoms, they must have the same structure.

true

false
Functional groups
In addition to carbon and hydrogen, hydrocarbons can also contain other elements. In fact, many common groups of atoms can occur
within organic molecules, these groups of atoms are called functional groups. One good example is the hydroxyl functional group. The
hydroxyl group consists of a single oxygen atom bound to a single hydrogen atom (-OH). The group of hydrocarbons that contain a
hydroxyl functional group is called alcohols. The alcohols are named in a similar fashion to the simple hydrocarbons, a prefix is
attached to a root ending (in this case "anol") that designates the alcohol. The existence of the functional group completely changes the
chemical properties of the molecule. Ethane, the two-carbon alkane, is a gas at room temperature; ethanol, the two-carbon alcohol, is a
liquid.
Ethanol
Ethanol, common drinking alcohol, is the active ingredient in "alcoholic" beverages such as beer and wine.