EXPERIMENT
Naming Organic
Compounds
Hands-On Labs, Inc.
Version 42-0181-00-03
Review the safety materials and wear goggles when
working with chemicals. Read the entire exercise
before you begin. Take time to organize the materials
you will need and set aside a safe work space in
which to complete the exercise.
Experiment Summary:
You will name a series of organic compounds based
on their chemical structure and provide the chemical
structure for organic compounds based on their
name.
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Experiment
Naming Organic Compounds
Learning Objectives
Upon completion of this laboratory, you will be able to:
●●
Discuss the IUPAC naming system.
●●
Define hydrocarbon and substituted hydrocarbon.
●●
List the prefixes and suffixes used in naming organic compounds.
●●
Identify the general molecular formula for hydrocarbon compounds.
●●
Describe the rules for naming organic compounds.
●●
Interpret chemical structures and name the organic compounds they represent.
●●
Draw the chemical structures of hydrocarbons and substituted hydrocarbons by interpreting
their chemical names.
Time Allocation: 2 hours
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Experiment
Naming Organic Compounds
Materials
Student Supplied Materials
Quantity
1
1
Item Description
Pen or pencil
Sheet of paper
Note: To fully and accurately complete all lab exercises, you will need access to:
1. A computer to upload digital camera images.
2. Basic photo editing software such as Microsoft® Word or PowerPoint®, to add labels, leader
lines, or text to digital photos. 3. Subject-specific textbook or appropriate reference resources from lecture content or other
suggested resources. Note: The packaging and/or materials in this LabPaq kit may differ slightly from that which is listed
above. For an exact listing of materials, refer to the Contents List included in your LabPaq kit.
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Experiment
Naming Organic Compounds
Background
The IUPAC Naming System
The International Union of Pure and Applied Chemistry (IUPAC) naming system provides a
systematic method of naming compounds around the globe. The IUPAC naming system was
designed with the fundamental principle that “each different compound should have a different
name.” Each IUPAC name for organic compounds consists of several parts: 3D relationship,
numbered substituents, number of carbons in the longest chain, and the ending suffix that
describes functional groups. See Figure 1.
Figure 1. Ascorbic acid (5R)-5-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxyfuran-2(5H)-one. The
unique IUPAC name for ascorbic acid (vitamin C) includes the numbered constituents, 3D
relationship of atoms, the numbers of carbons, and functional groups. ©Macrovector
The IUPAC naming system assures safety and consistency when using chemicals. It would be
difficult to replicate experiments if scientists used different names for the same compound. Safety
would also be a concern if there was no consistent system for naming because of the various
hazards associated with mixing chemicals.
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Experiment
Naming Organic Compounds
Naming Organic Compounds
Organic compounds, including hydrocarbons and substituted hydrocarbons, are named using
the IUPAC naming system. A hydrocarbon is an organic compound containing only carbon and
hydrogen atoms. Substituted hydrocarbons are organic compounds in which one or more of
the hydrogen atoms has been replaced by another kind of atom or group of atoms, such as a
halogen. A brief introduction to the IUPAC naming conventions for hydrocarbons and substituted
hydrocarbons is described below.
1. Identify the longest, continuous carbon chain (parent chain) in the compound structure. Circle
the parent chain to differentiate it from other components, as shown in the examples below.
Extra attention should be paid to ethyl, propyl, and butyl groups, etc. that “appear” as side
chains. Remember the parent chain includes the longest continuous chain of carbons.
Figure 2. Circled parent chains of two organic compounds.
2. Count the total number of carbons in the parent chain and determine the prefix. See Table
1. For example, the molecule in Figure 2 with 6 carbons would have a name including the
prefix “hex-,” and the molecule with 7 carbons would have a name including the prefix
“hept-.” The number of carbons in the parent chain may or may not be equal to the total
number of carbons in the structure, as shown in Figure 2. If other carbons exist in the
structure as side chains, they will be named as substituents.
Table 1. Prefixes for 1-10 Hydrocarbons
Number of Carbon Atoms
1
2
3
4
5
6
7
8
9
10
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Prefix
MethEthPropButPentHexHeptOctNonDec-
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Experiment
Naming Organic Compounds
3. Identify a suffix based on whether the parent strand has only single bonds (“-ane”), one or
more double bonds (“-ene”), or one or more triple bonds (“-yne”). For example, a saturated
hydrocarbon, or hydrocarbon consisting of only single carbon-carbon bonds, is known as
an alkane and contains the suffix “-ane.” An unsaturated hydrocarbon is a hydrocarbon
consisting of either double or triple carbon-carbon bonds. An unsaturated hydrocarbon with a
carbon-carbon double bond, is called an alkene and contains the suffix “-ene.” An unsaturated
hydrocarbon with a triple carbon-carbon bond is called an alkyne and contains the suffix
“-yne.” See Table 2 for examples of the name, molecular structure, and formula of compounds
containing single, double, and triple carbon-carbon bonds.
Table 2. Hydrocarbon names, molecular formulas, and structures.
Number
of Carbon
Atoms
Carbon
Bond
Type(s)
General
Molecular
Formula
Molecular
Formula
Name
1
Single
CnH2n+2
CH4
Methane
2
Single
CnH2n+2
C2H6
Ethane
3
Single
CnH2n+2
C3H8
Propane
4
Single
CnH2n+2
C4H10
Butane
2
Double
CnH2n
C2H4
Ethene
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Structure
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Experiment
Naming Organic Compounds
Number
of Carbon
Atoms
Carbon
Bond
Type(s)
General
Molecular
Formula
Molecular
Formula
Name
3
Double
and single
CnH2n
C3H6
Propene
4
Double
and single
CnH2n
C4H8
1-Butene
2
Triple
CnH2n-2
C2H2
Ethyne
3
Triple and
single
CnH2n-2
C3H4
Propyne
4
Triple and
single
CnH2n-2
C4H6
1-Butyne
Structure
Note: The general molecular formula uses “n” as an integer representing the number of carbons
present.
Note: In order for a hydrocarbon to have a double or triple carbon-carbon bond, there must be 2 or
more carbons present in the compound. Therefore, only methane can exist and there is no methene
or methyne.
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Experiment
Naming Organic Compounds
4. Follow the steps below for numbering the carbons in the parent chain of a single bonded
carbon chain.
a. Begin on the end with the closest substituents to ensure the name includes the lowest
possible numbers. For example, in Figure 3A, the carbons are numbered from left to
right because the substituents are closest to the leftmost carbon. If substituents are
in equivalent positions, then the numbering priority is assigned based on alphabetical
order. For example, in Figure 3B the bromine and chlorine atoms exist in equivalent
positions, so the lowest numbered carbon is assigned nearest the bromine since “b”
comes before “c” in the alphabet.
Figure 3. Naming single bonded substituted hydrocarbons. A. Single bonded 5 carbon molecule
(circled and numbered in red) with methyl and chlorine substituents (circled in blue and green).
B. Single bonded 5 carbon molecule (circled and numbered in red) with bromine and chlorine
substituents (circled in purple and green).
b. Name the substituents as alkyl groups, with the number of the carbon that it is
attached to in front to indicate the location of the group. An alkyl group is a fragment
of a molecule formed by removing a hydrogen and has the general formula CnH2n+1.
For example, a methyl group (CH3) is the fragment of a methane molecule (CH4). An
alkyl group name typically consists of the prefix, based on the number of carbons in
the group, and the suffix “–yl.” For example, in Figure 3A there is a methyl attached
to the #2 carbon so it is named “2-methyl.”
c. Halogens get a slightly different name; for example, chlorine becomes “chloro” and
bromine becomes “bromo.” In Figure 3A the chlorine atom attached to the #3 carbon
is named “3-chloro.”
d. Substituent names are listed in alphabetical, not numerical order. It may also be
helpful to circle the substituents to differentiate them from the parent chain, as
shown in Figure 3.
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Experiment
Naming Organic Compounds
5. The same rules apply when numbering a carbon chain with a double or triple bond; however,
the numbering priority is given to the end of the chain with the double or triple bond. The
lowest numbered carbon of the double or triple bond must be included in the name. For
example, in Figure 4A the double bond is on the #2 carbon of a 5 carbon chain and is included
in the name as “2-pentene.” In Figure 4B the triple bond is on the #1 carbon of a 5 carbon
chain and is included in the name as “1-pentyne.”
Figure 4. Numbering priority of double and triple bonded substituted hydrocarbon. A. 5 carbon
molecule (circled and numbered in red) with a double bond with a bromine and two methyl
substituents (circled in purple and blue). B. 5 carbon molecule (circled and numbered in red)
with a triple bond and two chlorine substituents (circled in green).
6. When two or more substituents are identical, list them together and indicate the appropriate
prefix: “di-,” “tri-,” “tetra-,” etc. Give each substituent its own number. For example, in Figure
4A there are two methyls and indicated in the name as “dimethyl.” In Figure 4B there are two
chlorines and indicated as “dichloro” in the name.
7. Use hyphens to separate numbers from letters and commas to separate numbers from
numbers. Review the examples in Figure 3 and Figure 4: hyphens occur between numbers
and letters and commas occur between numbers.
Hydrocarbons are among the
most important compounds on Earth.
Even though some hydrocarbons are
explosive or toxic, chemists can modify them
with the addition of chemical substituents
to create some of the most useful products!
Without these hydrocarbon derivatives we
would not have food, trees, fossil fuels,
industrial chemicals, plastics, rubber, dyes,
alcohol, and many medications such as
antibiotics.
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Experiment
Naming Organic Compounds
Exercise 1: Naming Organic Compounds
In this exercise, you will practice naming and drawing the structures of hydrocarbons and
substituted hydrocarbons.
Procedure
Note: Use the information in the background to successfully complete this exercise.
Part 1: Hydrocarbons
1. View the first structural formula provided in Data Table 1 of your Lab Report Assistant. Follow
the steps below and write each part of the name on a piece of paper.
a. Identify the parent chain of the compound.
b. Count the number of carbon atoms and determine the type of carbon-carbon bonds
(single, double, or triple) to record the base name of the compound with the correct
suffix.
c. Number the carbons by beginning on the end with the closest substituent(s) for
single bonded compounds, or the end nearest the double or triple bond if present, to
ensure the lowest possible numbers are used in the final compound name.
2. Record the name of the compound structure in Data Table 1.
3. Repeat steps 1-2 for the remaining compound structures in Data Table 1.
4. View the first compound name provided in Data Table 2 of your Lab Report Assistant. Follow
the steps below and draw each part of the structure on a piece of paper.
a. Determine the number of carbons present in the compound based on the base name.
b. Draw the carbon chain and include any double or triple bonds if indicated in the suffix
of the base name.
c. Number each carbon. The carbons may be numbered from left to right or right to left.
d. Check that each carbon atom has a total of 4 bonds.
5. Record the compound structure of the first compound name in Data Table 2 directly in each
cell of the Word® document using text and inserted shapes, or by using photo editing software
such as Microsoft PowerPoint®.
6. Repeat steps 4-5 for the remaining compound names in Data Table 2.
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Experiment
Naming Organic Compounds
Part 2: Substituted Hydrocarbons
7. View the first compound structure provided in Data Table 3 of your Lab Report Assistant.
Follow the steps below and write each part of the name on a piece of paper.
a. Identify the parent chain of the compound.
b. Count the number of carbon atoms and determine the type of carbon-carbon bonds
(single, double, or triple) to record the base name of the compound with the correct
suffix.
c. Number the carbons by beginning on the end with the closest substituent(s) for
single bonded compounds, or the end nearest the double or triple bond if present, to
ensure the lowest possible numbers are used in the final compound name.
d. Write the names of any substituents (i.e. methyl, chloro) and the number of the
carbon atom that they are attached to.
e. Include the correct prefix (if any) for two or more identical substituents.
f. Write the name of the hydrocarbon by alphabetizing the substituents, followed by
the base name of the carbon compound.
g. Use hyphens to separate numbers from letters and commas to separate numbers
from numbers.
8. Record the name of the compound structure in Data Table 3.
9. Repeat steps 7-8 for the remaining compound structures in Data Table 3.
10.View the first compound name provided in Data Table 4 of your Lab Report Assistant. Follow
the steps below and draw each part of the structure on a piece of paper.
a. Determine the number of carbons present in the compound based on the base name.
b. Draw the carbon chain and include any double or triple bonds if indicated in the suffix
of the base name.
c. Number each carbon. The carbons can be numbered from left to right or right to left.
d. Draw any substituents on the corresponding carbon atom for which is indicated in
the name. Refer to Figures 2 and 3 in the Background for a visual representation of
numbered carbons with corresponding substituents.
e. Check that each carbon atom has a total of 4 bonds.
11.Record the compound structure of the first compound name in Data Table 4 directly in each
cell of the Word® document using text and inserted shapes, or by using photo editing software
such as Microsoft PowerPoint®.
12.Repeat steps 10-11 for the remaining compound names in Data Table 4.
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Experiment
Naming Organic Compounds
Questions
A. Provide the molecular formula for the following hydrocarbons:
a. Hexane
b. Methane
c. Propyne
d. 1-pentene
e. 2-octyne
f. Decane
g. Heptane
h. 4-nonene
B. Describe the difference between a saturated hydrocarbon and an unsaturated hydrocarbon.
Name a total of 3 saturated hydrocarbons and a total of 3 unsaturated hydrocarbons from
Data Table 1 and Data Table 2.
C. In your own words, list the rules for naming hydrocarbons and substituted hydrocarbons. Be
detailed in listing all rules including the priority for numbering carbons, prefixes and suffixes,
and the structure of the name.
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