Organic Chemical Compounds
Objective:
There are millions of known carbon compounds. In this experiment, several of the major families of
carbon compounds will be investigated, which will demonstrate some of the characteristic properties and
reactions of each family.
Introduction:
Carbon atoms have the correct electronic configuration and size to enable long chains or rings of
carbon atoms to be built up. This ability to form long chains is unique among the elements, and is called
catenation. There are known molecules that contain thousands of carbon atoms, all of which are attached
by covalent bonds among the carbon atoms. No other element is able to construct such large molecules
with its own kind.
Hydrocarbons:
The simplest types of carbon compounds are known as hydrocarbons. Such molecules contain only
carbon atoms and hydrogen atoms. There are various sorts of molecules among the hydrocarbons,
differing in the arrangement of the carbon atoms in the molecule, or in the bond between the carbon
atoms. Hydrocarbons consisting of chain-like arrangements of carbon atoms are called aliphatic
hydrocarbons, whereas molecules containing the carbon atoms in a closed ring shape are called cyclic
hydrocarbons. For example, the molecules hexane and cyclohexane represent aliphatic and cyclic
molecules, each with six carbon atoms:
Hexane image
Cyclohexane image
Notice that all the bonds between carbon atoms in hexane and cyclohexane are single bonds.
Molecules containing only singly bonded carbon atoms are said to be saturated. Other molecules are
Other molecules are known in which some of the carbon atoms may be attached by double or even triple
bonds and are said to be unsaturated. The following are representations of the molecules 1-hexene and
cyclohexene, which contain double bonds:
1-hexene image
cyclohexene
Hydrocarbons with only single bonds are not very reactive. One reaction all hydrocarbons undergo,
however, is combustion. Hydrocarbons react with oxygen, releasing heat and/or light. For example, the
simplest hydrocarbon is methane, CH4, which constitutes the major portion of natural gas. Methane burns
in air, producing carbons dioxide, water vapor, and heat:
CH4 + 202  CO2 + 2H2O
Single-bonded hydrocarbons also will react slowly with the halogen elements (chlorine and bromine).
A halogen atom replaces one or more of the hydrogen atoms of the hydrocarbons. For example, if
methane is treated with bromine, bromomethane is produced, with concurrent release of hydrogen
bromide:
CH4 + Br2  CH3Br + HBr
The hydrogen bromide produced is generally visible as a fog evolving from te reaction container,
produced as the HBr mixes with water vapor in the atmosphere.
Molecule with double and triple bonds are much more reactive than single-bonded compounds.
Unsaturated hydrocarbons undergo reactions at the site of the double or triple bond, in which the
fragments of some outside reagent attach themselves to the carbon atoms that had been involved in the
double or triple bond. Such reactions are called addition reactions. The orbitals of the carbons atoms that
had been used for the extra bond instead are used for attaching the fragments of the new reagent. For
example, the double-bonded compound ethylene will react with many reagents:
CH2CH2 + H2  CH3CH3
CH2CH2 + HBr  CH3CH2Br
CH2CH2 + H2O  CH3CH2OH
CH2CH2 + Br2  CH2BrCH2Br
Organic Lab
Notice that in all of these reactions of ethylene, the product is saturated and no longer contains a
double bond. Many of the reactions of t ethylene indicated only take place in the presence of a catalyst, or
under reaction conditions that we will not be able to investigate in this experiment.
Cyclic compounds containing only single or double bonds undergo basically the same reactions
indicated earlier for aliphatic hydrocarbons. One class of cyclic compounds, called the aromatic
hydrocarbons, have unique properties that differ markedly from those we have discussed. The parent
compound of this group of hydrocarbons is benzene:
Benzene images
Although we typically draw the structure of benzene indicating double bonds around the ring of carbon
atoms, in terms of its reactions, benzene behaves as though it did not have any double bonds. For
example, if elemental bromine is added to benzene (with suitable catalyst), benzene does not undergo
addition reaction as would be expected for a compound with double bonds. Rather, it undergoes a
substitution reaction of the sort that would be expected for single-bonded hydrocarbons:
Benzene image
Bromobenzene
This reaction indicates that perhaps benzene does not have any double bonds in reality. Several
Lewis dot structures can be drawn for benzene, with the “double bonds” in several different locations in
the ring. Benzene exhibits the phenomenon of resonance; that is, the structure of benzene shown, as well
as any other structure that might be drawn on paper, does not really represent the true electronic
structure of benzene. The electrons of the “double bonds” of the benzene are, in fact, delocalized around
the entire ring of the molecule and are not concentrated in any particular bonds between carbon atoms.
The ring structure of the benzene is part of many organic molecules, including some very common
biological compounds.
Functional Groups
While the hydrocarbons just described are of interest, the chemistry of organic compounds containing
atoms other than carbon and hydrogen is far more varied. When another atom, or group of atoms, is
added to a hydrocarbons framework, the new atom frequently imparts its own very strong characteristic
properties to the resulting molecule. An atom or group of atoms that is able to impart new and
characteristic properties to an organic molecule is called a functional group. With millions of carbon
compounds known, it has been helpful to chemists to divide these compounds into families, based on
what functional group they contain. Generally it is found that all the members of a family containing a
particular functional group will have many similar physical properties and will undergo similar chemical
reactions.
A. Alcohols
Simple hydrocarbon chains or rings that contain a hydroxyl group bonded to a carbon atom are called
alcohols. The following are several:
Methanol image
Ethanol image
1-propanol image
The –OH group of alcohols should not be confused with the hydroxide ion, OH -. Rather than being
basic, the hydroxyl group makes the alcohols in many ways like water, H-OH. For example, the smaller
alcohols are fully miscible with water in all proportions. Alcohols are similar to water in that they also react
with sodium, releasing hydrogen. Alcohols, however, react more slowly with sodium than does water.
Many alcohols can be oxidized by reagents, such as permanganate ions or dichromate ions, with the
product depending on the structure of the alcohol. For example, ethyl alcohol is oxidized to acetic acid:
When wine spoils, vinegar is produced. On the other hand, 2-propanol is oxidized to propanone (acetone)
by such oxidizing agents:
Ethanol image
Acetic acid image
2-propanol image
Acetone
Alcohols are very important in biochemistry, since many biological molecules contain the hydroxyl group.
For example, carbohydrates are alcohols, with a particular molecule generally containing several hydroxyl
groups.
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B. Aldehydes and Ketones
An oxygen atom that is double bonded to a carbons atom of a hydrocarbon chain is referred to as a
carbonyl group. Two families of organic compounds contain the carbonyl function, with the difference
between the families having to do with where along the chain of carbon atoms the oxygen atom is
attached. Molecules having the oxygen atoms attached to the first (terminal) carbon atom of the chain are
called aldehydes, whereas molecule having the oxygen atom attached to an interior carbon atom are
called ketones.
Aldehydes are intermediates in the oxidation of alcohols. For example, when ethyl alcohol is oxidized,
the product is first acetaldehyde, which is then further oxidized to acetic acid:
ethanolacetaldehydeacetic acid
Ketones are the end product of the oxidation of alcohols in which the hydroxyl group is attached to an interior
carbon atom (called secondary alcohols, as was indicated earlier for 2-propanol.
Aldehydes and ketone are important biologically because all carbohydrates are also either aldehydes or
ketones, as well as being schwanzen (alcohols). The common sugars glucose and fructose are shown next.
Notice that glucose is an aldehyde, whereas fructose contains the ketone functional group.
Glucose image
Fructose image
Molecules such as glucose and fructose, which contain both carbonyl and hydroxyl function, are easily
oxidized by Benedict’s reagent. Benedict’s reagent is a specially prepared solution of copper(II) ion that is
reduced when added to certain sugars, producing a precipitate of rep copper(I) oxide. Benedict’s reagent
is the basis for the common test for sugars in the urine of diabetics. A strip of paper or tablet containing
Benedict’s reagent is added to a urine sample. The presence of sugars is confirmed if the color of the test
reagent changes to the color of copper(I) oxide. Benedict’s reagent reacts only with aldehydes and
ketones that also contain a correctly located hydroxyl group, but will not react with simple aldehydes or
ketones.
C. Organic Acids
Molecules that contain the carboxyl group at the end of a carbon atom chain behave as acids. For
example, the hydrogen atom of the carboxyl group of acetic acid ionizes as:
Acetic acidacetate ion + hydrogen ion
On paper, the carboxyl group looks like a cross between the carbonyl group of aldehydes and the
hydroxyl group of alcohols, but the properties of the carboxyl group are completely different from either of
these. The hydrogen atom of the carboxyl group is lost by organic acids because the remaining ion has
more than one possible resonance form, which leads to increased stability fro this ion, relative to the nonionized molecule.
Organic acids are typically weak acids, with only a few of the molecules in a sample being ionized at
any given time. However, organic acids are strong enough to react with bicarbonate ions or to cause an
acidic response in pH test papers or indicators.
Organic Lab
D. Organic Bases
There are several types of organic compounds that show basic properties, the most notable of such
compounds forming the family of amines. Amines are considered to be organic derivatives of the weak
base ammonia, in which one or more of the hydrogen atoms of ammonia is replaced by chains or rings of
carbon atoms. The following are some typical amines:
Ammonia image
Methylamine image
Dimethylamine image
Ethyldimethylamine image
Like ammonia, organic amines react with water, releasing hydroxide ions from water molecules:
NH3+H2ONH4++OHCH3NH2+H2OCH3NH3++OHAlthough amines are weak bases (not fully dissociated), they are basic enough to cause a color change
in pH test paper and indicators, and are able to complex many metal ions in a similar manner to
ammonia.
The so-called amino group, -NH2, found in some amines (primary amines) is also present in the class of
biological compounds called amino acids. Many of the amino acids from which proteins are constructed
are remarkably simple, considering the overall complexity of proteins. The amino acids found in human
protein contain a carboxyl group, whit an amino group attached to the carbon atom next to the carboxyl
group in the molecule’s carbon chain. This sort of amino acid is referred to as an alpha amino acid. One
simple amino acid found in human protein is shown her:
Glycine (2-aminoethanoic acid)
Safety Precautions
 Safety eyewear approved by your institution must be worn at all times while you are in the
laboratory, whether or not you are working on an experiment.
 Assume that all the organic substances are highly flammable. Use only small quantities, and keep
them away from open flames. Use a hot water bath if a source of heat is required.
 Assume that all substances are toxic and are capable of being absorbed through the skin. Avoid
contact and wash after use. Inform the instructor of any spills.
 Assume that the vapor of all organic substances are harmful. Use small quantities and work in the
fume exhaust hood.
 Sodium reacts violently with water, liberating hydrogen gas and enough heat to ignite the hydrogen.
Do not dispose of sodium in the sinks. Add any excess sodium to a small amount of ethyl alcohol,
and allow the sodium to react fully with the alcohol before disposal.
 Potassium permanganate, potassium dichromate, and Benedict’s reagent are toxic. Permanganate
and dichromate can harm skin and clothing. Exercise caution and wash after use. Chromium
compounds are suspected mutagens/carcinogens.
 Bromine causes extremely bad burns to skin, and its vapors are extremely toxic. Work with bromine
only in the fume exhaust hood, and handle the bottle with a towel while dispensing.
 Dispose of all materials as directed by the instructor.
Apparatus/Reagents Required
Hexane, 1-hexane, cyclohexane, cyclohexene, toluene, ethyl alcohol, methyl alcohol, isopropyl alcohol, nbutyl alcohol, n-pentyl alcohol, n-octyl alcohol, 10% formaldehyde solution, 10% acetaldehyde solution,
acetone, 10% glucose, 10% fructose, acetic acid, propionic acid, butyric acid, ammonia, 10% butylamine,
1% bromine in methylene chloride, 1% aqueous potassium permanganate, Benedict’s reagent, sodium
pellets, 5% acidified potassium dichromate solution, pH paper, 10% sodium bicarbonate solution, 1M
copper sulfate solution
Organic Lab
Procedure
Record all data and observations directly on the report pages in ink.
A. Hydrocarbons
o Your instructor will ignite small portions of hexane, 1-hexene, cyclohexene, and toluene to
demonstrate that they burn readily (do not attempt this yourself). Notice that toluene (an aromatic
compound) burns with a much sootier flame than the other hydrocarbons. This is characteristic of
aromatics.
o Obtain small (0.5mL) portions of hexane, 1-hexene, cyclohexene, and toluene in separate small
test tubes. Take the test tubes to the exhaust hood, and add a few drops of 1% bromine to each.
Those samples containing double bonds will decolorize the bromine immediately (addition
reaction). Those sample that did not decolorize the bromine immediately will gradually lose the
bromine color (substitution reaction).
B. Alcohols
o
o
o
o
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Obtain small samples of methyl, ethyl, isopropyl, n-butyl, n-pentyl, and n-octyl alcohols in
separate clean test tubes. Add an equal quantity of distilled water to each test tube, stopper, and
shake.
Record the solubility of the alcohols in water. In alcohols with only a few carbon atoms, the
hydroxyl group contributes a major portion of the molecule’s physical properties, making such
alcohols miscible with water. As the carbon atom chain of an alcohol gets larger, the alcohol
becomes more hydrocarbon in nature and less soluble in water.
Obtain 2 drop samples of methyl, ethyl, isopropyl, n-butyl, n-pentyl, and n-octyl alcohols in
separate clean test tubes.
Wearing disposable gloves, add 10 drops of acidified potassium dichromate to each sample,
transfer to a hot water bath, and heat until a reaction is evident. Dichromate ions oxidize primary
and secondary alcohols.
Obtain small samples of methyl, ethyl, isopropyl, n-butyl, n-pentyl, and n-octyl alcohols in
separate clean test tubes.
Have the instructor add a tiny pellet of sodium to each test tube. The vigor of the reaction
depends on the structure of the alcohol. Smaller alcohols are more reactive than larger alcohols.
Wait until all the sodium in the test tubes have completely reacted. Then add about 5mL of
distilled water to the test tubes, and test the resulting solution with pH paper. The alkoxide ion
that remains from the alcohols after the reaction with the sodium is strongly basic in aqueous
solution.
C. Aldehydes and Ketones
 Obtain 2 drop samples of formaldehyde, acetaldehyde, acetone, glucose, and fructose in
separate test tubes.
 Wearing gloves, add 10 drops of acidified potassium dichromate solution to each sample, and
transfer the test tubes to a hot water bath. Aldehydes are oxidized by dichromate, being
converted into organic acids.
 Record which samples change color. Obtain small samples of formaldehyde, acetaldehyde,
acetone, glucose, and fructose in separate test tubes.
 To each test tube add 5mL of Benedict’s reagent, and transfer to a hot water bath. Molecules
containing a hydroxyl group next to a carbonyl group on a carbon atom chain will cause a color
change in Benedict’s reagent. This test is applied to urine for the detection of sugar.
D. Organic Acids
o Obtain small samples of acetic acid, propionic acid, and butyric acid in separate small test tubes.
o Add 5mL of 10% sodium bicarbonate solution to each test tube: a marked fizzing will result as the
acids release carbon dioxide from the bicarbonate.
o Obtain small samples of acetic acid, propionic acid, and butyric acid in separate small test tubes.
o Add 5mL of water to each test tube, and test the solution with pH paper.
Organic Lab
E. Organic Bases
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Obtain small samples of aqueous ammonia and of n-butylamine solution in separate
small test tubes.
Determine the pH of each sample with pH test paper.
Add a few drops of 1M copper sulfate solution to each test tube and shake. The color
of the copper sulfate solution should darken as the metal/amine complex is formed.
Organic Lab

Organic Chemical Compounds Pre-Laboratory Questions
Draw the structural formulas for each of the following substances. If the common name of the substances is given
write the IUPAC name for the substance.
hexane
IUPAC name ___________________________
isopropyl alcohol
IUPAC name ___________________________
1-hexene
IUPAC name ___________________________
formaldehyde
IUPAC name ___________________________
cyclohexane
IUPAC name ___________________________
acetaldehyde
IUPAC name ___________________________
cyclohexene
IUPAC name ___________________________
acetone
IUPAC name ___________________________
toluene
IUPAC name ___________________________
acetic acid
IUPAC name ___________________________
methyl alcohol
IUPAC name ___________________________
butyric acid
IUPAC name ___________________________
ethyl alcohol
IUPAC name ___________________________
n-butylamine
IUPAC name ___________________________
Results/Observations
A. Hydrocarbons
Observations of igniting
Which compounds decolorized bromine immediately?
Which compounds decolorized bromine on exposure to light?
Organic Lab
Which compounds produced an HBr fog?
Which compounds caused a color change in KmnO4 ?
B. Alcohols
Which alcohols were fully soluble in water?
Which alcohols caused a color change when tested with dichromate ion?
Relative vigor of reaction of alcohols with sodium
Approximate pH of water solutions of alcohol/sodium product
C. Aldehydes and Ketones
Which aldehydes/ketones caused a color change when tested with dichromate ion?
Which aldedhydes/ketones caused a color change when tested with Benedict’s reagent?
D. Organic Acids
Observations on test with bicarbonate
Approximate pH of aqueous solution of organic acid samples
E. Organic Bases
Approximate pH of aqueous solutions of ammonia/n-butylamine
Observations of adding CuSO4
Questions
1. When sodium bicarbonate was added to an organic acid sample, carbon dioxide was evolved. Is this test
specific for organic acids, or does it apply to acids in general? Write the balanced equation for the
process.
Organic Lab