An Organic Chemistry Self-Study Exercise
Naming Simple and Unsaturated Hydrocarbons

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1.  In studying inorganic chemistry,  you learned that the carbon atom has a valence (oxidation number) that is usually 4.   But in organic chemistry the term bond is used in place of valence.   Thus we say that the carbon atom has (how many?) ______ bonds? 

2.                                                                                                                  4
Hydrogen has a valence of +1, so it must have (how many? )  _____ bonds? 
3.                                                                                                                  1

Oxygen, with a valence of -2, we can describe as having _______ 
4.                                                                                                              two bonds

In writing chemcial symbols or formula, we can draw short lines to represent bonds.   Hydrogen, with one bond, can be written thus:     H-
Oxygen has two bonds.   How can it be written? ________ 
5.                                                                                                               O= or -O-

Carbon has four bonds.  They are usually shown as four short lines distributed evenly around the symbol for carbon.   Try to draw it. __________ 
6.                                                                                                                    |

Carbon has four bonds.  Hydrogen has one bond.
If a hydrogen atom were connected to each bond of a carbon atom, there would be
(how many?) _________ hydrogen atoms? 
7.                                                                                                                    4

The simplest way to write the molecular formula for a compound of one carbon atom and four hydrogen atoms is ___________ 
8.                                                                                                                CH4

The name of CH4 is methane.   Pronounce it meth'ane.  It rhymes with "pane."
Write the name of the compound whose formula is CH4

We are talking about a compound named methane.  The formula for methane is CH4.
That still does not tell us all we need to know about methane.
We need to show the structure of the methane moelcule.

The carbon atom has (how many?) bonds.  _________ 
 The hydrogen atom has (how many?) bonds. _________                                4 
10.                                                                                                                  1

Look at this structure:

The short line that represents each bond of the carbon atom also represents the bond of the hydrogen atom.  We say that each hydrogen atom shares one of the carbon atom's _______ 
11.                                                                                                               bonds

Using the symbol for carbon, draw two carbon atoms connected by one shared bond.________ 
12.                                                                                                               C-C

In the diagram C-C, the short line represents one of the bonds possessed by both carbon atoms.  Each atom has (how many?) ________ such bonds? 
13.                                                                                                                4

If each carbon atom has four bonds, and if this diagram:
shows the two atoms sharing one bond between them, how many more bonds should each atom be shown as possessing?  __________ 
14.                                                                                                              three

Draw the C-C diagram with all bonds shown. _________ 
                                                                                                               |   |

                                                                                                                |   |
How many hydrogen atoms can be added to this structure:
                                |   |
                                |   |
so that all bond requirements will be satisfied? ________ 
16.                                                                                                             six

Draw the structure of a compound that contains two carbon atoms and six hydrogen atoms____ 

Write the molecular formula for the compound whose structure you just drew.________ 
18.                                                                                                          C2H6

The compound C2H6 is called ethane.  Pronounce it eth'ane. It rhymes with "pane."
Are all bonds "satisfied" in the compound C2H6? _______ 
19.                                                                                                           Yes

The name of the compound CH4 is _________
The name of the compound C2H6 is _________ 
20.                                                                                                          methane

Methane has one carbon atom and four hydrogen atoms.
Ethane has two carbon atoms, and six hydrogen atoms.
Now we will look at a compound that has one more carbon atom.
Draw three carbon atoms connected by single (shared) bonds. ________ 
21.                                                                                                           C-C-C

How many hydrogen atoms can be attached to
in order to satisfy all bond requirements? _______ 
22.                                                                                                               8

The molecular formula for this compound is ________ 
23.                                                                                                          C3H8

Can you attach the same number of hydrogen atoms to each of the carbon atoms? _______ 

Draw a diagram to show the structure of C3H8  ________ 
25.                                                                                                       H  H  H

                                                                                                             |    |    |
                                                                                                             |    |    |
                                                                                                            H  H  H
The name of the compound is propane.  The molecular formula for propane is________? 
26.                                                                                                        C3H8

The name of CH4 is _________ 
27.                                                                                                        methane

The name of C2H6 is __________ 
28.                                                                                                       ethane

The name of C3H8 is __________ 
29.                                                                                                       propane

Draw four carbon atoms in a row, connected
by the fewest possible number of bonds. _______ 
30.                                                                                                     C-C-C-C

The total number of hydrogens that will satisfy
all bond requirements of C-C-C-C is ________ 
31.                                                                                                        10

The molecular formula for that compound is __________ 
32.                                                                                                       C4H10

The name of the compound is butane.  Pronounce it bew'tane.
The molecular formula for butane is ______________ 
33.                                                                                                       C4H10

The name of CH4 is ___________ 
34.                                                                                                       methane

The molecular formula of butane is ________ 
35.                                                                                                       C4H10

The name of C3H8 is ___________ 

The molecular formula of ethane is _________ 
37.                                                                                                        C2H6

The molecular formula for methane is ________ 
38.                                                                                                        CH4

The name of C2H6 is __________ 
39.                                                                                                        ethane

The name of C4H10 is __________ 
40.                                                                                                        butane

The molecular formula of propane is ____________ 
41.                                                                                                         C3H8

All of the compounds so far studied have names that end in _________ 
42.                                                                                                         ane

In organic chemistry there are a number of such "series" of compounds.
A series is named after the first compound in it.  This series, therefore,
is called the __________ series of hydrocarbons. 
43.                                                                                                        methane

There is a general formula for all compounds in the methane series:
So if there are four carbon atoms, n is 4, and 2n + 2 = 8 +2 = 10.
The compound is C4H10, and the name of that compound is _________ 
44.                                                                                                        butane

If there were five carbon atoms (n = 5),
the molecular formula of that member of the series would be _______ 
45.                                                                                                       C5H12

The name of C5H12 is pentane.  This name and the names
of the next few compounds in the methane series will be easy
to remember.  "Pent" means "five" in this and other words, such
as "Pentagon," which is a five-sided diagram, and "pentacle,"
which is a five-pointed star.
Draw the diagram for pentane _________ 
                                                                                                     H  H H  H  H

                                                                                                      |    |   |    |    |
                                                                                                      |    |   |    |    |
                                                                                                     H  H H  H  H
The next hydrocarbon in the series is hexane.
The prefix "hex" means "six," so the formula for hexane
(CnH2n+2) is ______ 
47.                                                                                                    C6H14

The prefix that means "seven" is "hept,"
and so the compound is ___________ 
48.                                                                                                   heptane

From the words "octet" and "octagon" we know that the
prefix meaning "eight" is ____________ 
49.                                                                                                   oct

The name of the hydrocarbon with eight carbon atoms is __________
Its formula is ___________ 
50.                                                                                                   octane

The next in line is nonane, which has (how many?) ______ carbon atoms.
It has the formula _________ 
51.                                                                                                   nine

The prefix meaning "ten" is "dec," which we already knew
from words like "decade" and "decimal".
The hydrocarbon decane (deck'ane) has (how many?) _______carbon atoms
and (how many?) ________ hydrogen atoms?
52.                                                                                                  10

Octane has (how many?) ________ carbon atoms? 
53.                                                                                                   8

Pentane has (how many?) ________ carbon atoms? 
54.                                                                                                   5

Heptane has (how many? _______ carbon atoms. 

Decane has (how many?) _______ carbon atoms. 
56.                                                                                                  10

Nonane has (how many?) ______ carbon atoms? 
57.                                                                                                  9

Hexane has (how many?) ______ carbon atoms? 
58.                                                                                                  6

Methane has (how many?) _____ carbon atoms? 
59.                                                                                                  1

The compound in the methane series that has
three carbon atoms is called ________. 
60.                                                                                                 propane

The compound in the methane series
that has two carbon atoms is called ________. 
61.                                                                                                ethane

The methane series compound with nine carbon atoms is _______. 
62.                                                                                                nonane

The general formula for compounds in the methane series is: 
63.                                                                                               CnH2n+2

The name of C7H16 is _______ 
64.                                                                                               heptane

The name of C6H14 is _______ 

65.                                                                                               hexane
The methane series compound with eight carbon atoms is ________ 
66.                                                                                               octane

The methane series compound with four carbon atoms is ________ 
67.                                                                                               butane

The name of CH4 is _________ 
68.                                                                                               methane

If a methane series compound has ten carbon atoms
it has (how many?) _____ hydrogen atoms
and its name is _______ 

                                                                                                  22, decane
The compound C5H12 is __________ 
70.                                                                                              pentane

Name, and write the formula for the first ten hydrocarbons in the
methane series in consecutive order. 
71.                                                                                             CH4,    methane

                                                                                                  C2H6,   ethane
                                                                                                  C3H8,    propane
                                                                                                  C4H10,  butane
                                                                                                  C5H12,  pentane
                                                                                                  C6H14,  hexane
                                                                                                  C7H16,  heptane
                                                                                                  C8H18,  octane
                                                                                                  C9H20,  nonane
                                                                                                  C10H22, decane
Draw two carbon atoms connected by a double bond.
That is, with two bonds shared by both atoms. _____ 

But since a carbon atom has only (how many?) ______ bonds,
each of the carbon atoms in the diagram has left only (how many?) _____ unused bonds. 
73.                                                                                                           4

How many hydrogen atoms can be attached
to each of the carbon atoms? ________ 
74.                                                                                                          2

The molecular formula of the compound is __________ 
75.                                                                                                          C2H4

Draw the diagram for the compound_______ 
76.  OR   OR

What is the name of the compound C2H6? _______ 

The difference between ethane, C2H6,
and this new compound, C2H4, is the
difference of the two hydrogen atoms resulting
from the different bonding of the carbon atoms.

There is a difference in the name, too.
Ethene is the name of the new compound
whose molecular formula is __________ 

78.                                                                                             C2H4
When the compound has a double bond between carbon atoms,
the name of the compound ends with _________ 
79.                                                                                            ene

Look at this structure:


How many hydrogen atoms can be connected to it
in order to complete all the bonds? ________ 

80.                                                                                            6
The molecular formula for the compound is _________ 
81.                                                                                            C3H6

Draw the structure of the compound ___________ 

The three-carbon comopund in the methane series is called propane.
The three-carbon compound in this new series is called _________. 
83.                                                                                           propene

A series of hydrocarbons can be buit up with a double bond
between two of the carbon atoms.
The series is named for the first compounds in the series.
The new series we are working with is called the ethene series.

Why isn't there a  "methene" to begin the series?
For a clue, think about the number of carbon atoms needed._________ 

84.                              Methane has only 1 carbon atom.  You need at
                                   least two carbon atoms to form a double bond.
                                   A characteristic of an "ethene" compound is that
                                   there is a double bond between two carbon atoms.

The four-carbon compound in the methane series is called ______
The four-carbon compound in the ethene series is called _______ 

85.                                                                                     butane
The five-carbon compound in the ethene series is called __________ 
86.                                                                                     pentene

There is a general formula for all of the compounds
in the ethene series
Thus there are always _______ as many hyrogen atoms as there are carbon atoms. 
87.                                                                                     twice

The formula for octene is ___________ 
88.                                                                                     C8H16

The general formula for the methane series is  CnH2n+2
The general formula for the ethane series is CnH2n

The ethene compound always has two fewer atoms than the methane compound.  Why? ______ 

89.                                                                                 The double bond in the ethene
                                                                                      takes away two possible
                                                                                      attachments for hydrogen atoms.
The formula for hexene is ____________ 
90.                                                                                           C6H12

The prefix "dec" as in "decade" and "decimal" means __________ 
91.                                                                                            ten

The formula for decene (dess'een) is __________ 
92.                                                                                           C10H20

The formula for decane is _________ 
93.                                                                                           C10H22

The formula for pentane is _________ 
94.                                                                                           C5H12

The formula for pentene is _________ 
95.                                                                                            C5H10

If the number of hydrogen atoms in a compound is twice
the number of carbon atoms, the name of the compound
ends in the suffix _______ 
96.                                                                                            ene

If the number of hydrogen atoms in a compound
is twice the number of carbon atoms plus 2,
the name of the compound ends in ________. 
97.                                                                                            ane

The name of C6H12 is _________ 
98.                                                                                           hexene

The name of C4H10 is _________ 
99.                                                                                           butane

The name of C5H10 is _________ 
100.                                                                                         pentene

The name of C9H18 is _________ 

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