1. Organic Chemistry
 Cover introduction, alkanes, &
cycloalkanes
 There will be two quizzes

2. Standards Covered Today:
1. Describe the features of a homologous series.
2. State names and draw structural formulas for
organic compounds using the IUPAC Naming
System.
3. Draw structural formulas and state names of non-cyclic
(straight chain) alkanes up to C10, including
isomers.
4. Draw structural formulas and state names of cyclic
structures up to C10

3. Introduction
 In all organic compounds,
 all carbon atoms must make four bonds,
 all oxygen atoms must make two bonds,
 all nitrogen atoms must make three bonds,
 all hydrogen atoms must make one bond,
 and all halogens must make one bond.

4. Names of Structures
 Lewis Structures
 Structural Formulas
 Condensed Formulas &
Structures
 Line Structures C6H14 or CH3(CH2)4CH3

5. Notes on Structures
 Structural Formula: shows all bonds including
hydrogen
 Condensed Formula: These are generally written
without lines indicating bonds, or showing lone pairs,
and parentheses are used for identical groups.
 Line Formula: Bonds are represented by lines,
carbon atoms are assumed to be present at the start
and finish of a line.
 Nitrogen, oxygen and halogens are labeled, but hydrogens
are only shown when bonded to a drawn atom.
 Each atom is assumed to have sufficient hydrogen atoms
around it to make it neutral.

6. Isomers
 Draw a structural formula for C4H10
 An isomer is a compound that has the same
molecular formula as another.
 Structural Isomers: these are isomers that differ in
their bonding sequence. They have different bond
connectivity.
CH3
CH3 CH2 CH2 CH3 CH3 CH
CH3
n-butane isobutane

7. Introduction to Nomenclature
of Organic Molecules
 Four Categories:
 Alkanes
 Alkenes
 Alkynes
 Cyclic Structures

8. Alkanes
 Alkanes are the simplest organic molecules,
they only contain C and hydrogen, and only
contain single bonds.
 Considered to be hydrocarbons
 Compounds that have the maximum number
of bonded hydrogens, are said to be
saturated.
 Therefore, alkanes are the most saturated
compounds
 General Formula: CnH2n + 2

9. Nomenclature for compounds
 The root name of the compound is based upon the
number of carbon atoms in the longest continuous
chain.
Number of C atoms Root
1 Meth-
2 Eth-
3 Prop-
4 But-
5 Pent-
6 Hex-
7 Hept-
8 Oct-
9 Non-
10 Dec-

10.  Any series that differs only by an increasing
number of –CH2- groups is known as a
homologous series. The individual members
are said to be homologs of each other.
 The series must contain the same functional
group.
H
C C
H
C
H H
H
C
H
C
H
H
H
H
H
CH3
H C C
H
H C
H3C C
H H
H
C
H
H
H
H
CH3
CH3
CH3
pentane
C5H12
isopentane
C5H12
neopentane
C5H12

11. IUPAC Naming System:
Alkanes
1) Find the longest continuous chain of carbon atoms. This is the
base name of the compound.
2) Number the longest chain beginning with the end nearest a
substituent.
3) Name the substituent groups attached to the longest chain as
alkyl groups. Also state the location of each alkyl group
according to its numbered carbon on the main chain.
4) When two or more substituents are present, list them in
alphabetical order. If two or more of the same alkyl groups are
present, use the prefixes di-, tri- etc. to avoid repetition.

12. Alkane Nomenclature
Examples
1) CH2CH3
H3C CH-CH2-CH2-CH3
3-methylhexane
3-methyl hexane
• If there are two chains of equal length, choose the
chain that has the highest number of substituents.
CH3
CH2
HC
HC
H3C
HC
H3C HC
CH2CH3
CH3
CH3
CH3
CH2
HC
HC
H3C
HC
H3C HC
CH2CH3
CH3
CH3

13.  Numbering starts at the end nearest a
substituent so that the alkyl substituents have
as low numbers as possible.
CH3
CH2
HC
HC
H3C
HC H3C HC
CH2CH3
CH3
CH3
CH3
CH2
HC
HC
H3C
HC
H3C HC
CH2CH3
CH3
CH3
Alkyl groups are named by replacing the –ane suffix of the alkane
name with –yl.
E.g. CH3CH3 Ethane CH3CH2- Ethyl group
CH3CH2CH3 PropaneCH3CH2CH2- Propyl group

14.  Prefixes are used when there are more
than one type of alkyl substituent.
 Di = 2
 Tri = 3
 Tetra = 4
 Penta = 5
 The prefixes do not count when
alphabetizing.

15. CH3
CH2
HC
HC
H3C
HC
H3C HC
CH2CH3
CH3
CH3
3-ethyl-2,4,5-trimethylheptane

16. Recognizing Types of
Substitution
H
R C
H
R
R C
H
R
R C
R
Primary
1o carbon
Secondary
2o carbon
Tertiary
3o carbon

17. Cycloalkanes
 Cycloalkanes are simply alkanes that are cyclic.
 Just add cyclo-before their name.
 Notice the general formula for cycloalkanes is CnH2n
H2
C H2C
H2C CH2
CH2
H2
C
H2C CH2
cyclopropane
C3H6
cyclopentane
C5H10

18. Two simple rules of
cycloalkanes
 Rule A: Decide whether the cyclic or acyclic (non-cyclic)
portion contains more carbons. This
determines the base name. (Alkyl substituted
cycloalkane or cycloalkane substituted alkane).
 Rule B: Carbons are numbered to give the lowest
numbers for substituted carbons.
CH3
CH3
CH
CH3
CH
CH3
methylcyclopentane (1,2-dimethylpropyl)cyclohexane

19.  Numbering starts at the most substituted carbon,
and goes around in order to give the lowest
numbers.
H
CH3
H3C
CH3
1,1,3-trimethylcyclopentane
1,1,3-trimethylcyclopentane
• When there are more acyclic than cyclic carbons, the cyclic
part becomes a cycloalkyl substituent.
4-cyclopropyl-3-methyloctane
4-cyclopropyl-3-methyloctane

20. Complex Substituents
These are named as follows:
(a) The base alkyl group is numbered staring with the carbon
bonded to the main chain.
(b)The substituents are listed with the appropriate numbers, and
parentheses are used to separate the substituent name.
CH3
C-CH2
CH3
CH3
CH-CH3
a (1,1,3-trimethylbutyl) group

21. Examples
 Draw structures for the
following compounds:
1.) 3-ethyl-3-methylpentane
2.) 3-methyl-5-propylnonane
3.) 2,2,4,4-
tetramethylhexane
4.) pentylcyclohexane
5.) 2,3-dimethyl-4-
propylnonane
 Give the IUPAC names of the
following alkanes:
1.) (CH3)2CHCH2CH(C2H5)C(CH3)3
2.)
3.) (CH3CH2)3CH
4.) (CH3)2CH(CH2)3CH3

22. Physical Properties of Alkanes
 Nonpolar
 What type of intermolecular forces?
Dispersion Forces
 Since weak interactions….so low boiling point and
melting point
 As molecular weight increases, interactions
increase
 As interactions b/w molecules increase, so does the
strength of the interactions….
 So what conclusions can we make?

23.  The higher molecular weights…..
Leads to liquids, then solids
 The more branches…
More compact structure, surface area
decreases
Less contact between molecules, dispersion
forces decrease, so lower boiling point

24. Try these:
 Arrange in increasing boiling point:
a. CH3CH2CH2CH3, CH3CH2CH2CH2CH2CH3,
CH3(CH2)8CH3
b. CH3(CH2)6CH3, CH3C(CH3)2CH2CH(CH3)2,
CH3CHCH3(CH2)4CH3
c. 2-methyl butane, 2,2-dimethylpropane,
pentane

25.  Alkene and Alkyne Nomenclature
Make sure you study the different functional
groups over the break (sheet of paper with
table on it)
 This will need to be memorized for the quiz
and test.
 Quiz when we get back!

26. Elements of Unsaturation
 A saturated hydrocarbon: CnH2n+2
 Each multiple bond (and each ring)
decreases the number of H’s by two.
 Each of these is an element of unsaturation.
 To calculate: find number of H’s if it were
saturated, subtract the actual number of H’s,
then divide by 2.

27. Propose a Structure for C5H8
First calculate the number of elements
of unsaturation.
Remember:
A double bond is one element of
unsaturation.
A ring is one element of unsaturation.
A triple bond is two elements of
unsaturation.

28. Alkene Nomenclature
 Parent is longest chain containing the double
bond.
 -ane changes to -ene. (or -diene, -triene)
 Number the chain so that the double bond
has the lowest possible number.
 In a ring, the double bond is assumed to be
between carbon 1 and carbon 2.

29. Try these:
CH2 CH CH2 CH3
1-butene
CH3 C
CH CH3
CH3
2-methyl-2-butene
CH3
3-methylcyclopentene
CHCH2CH3
H3C
2-(1-methyl propyl)-1,3-cyclohexadiene
3-propyl-1-heptene

30. Geometric Isomerism
 Similar groups on same side of double bond,
alkene is cis.
 Similar groups on opposite sides of double bond,
alkene is trans.
C C
CH3
H
H
CH3CH2
C C
Br
H
Br
H
trans-2-pentene cis-1,2-dibromoethene

31. Alkynes
 Alkynes contain a triple bond.
 General formula is CnH2n-2
 Two elements of unsaturation for each triple
bond.

32. Alkyne Nomenclature
 Find the longest chain containing the triple
bond.
 Change -ane ending to -yne.
 Number the chain, starting at the end closest
to the triple bond.
 Give branches or other substituents a
number to locate their position.

33. Try these
CH3 C CH
CH3 C C CH2 CH2 Br
CH3
CH3 CH
CH3
CH2 C C CH
CH3
propyne
5-bromo-2-pentyne
2,6-dimethyl-3-heptyne
CH3
CH2 CH CH2 CH
C CH 3-methyl-1-hexyn-5-ene

34. Practice Problems
 Two worksheets

35. Agenda
 Review of alkanes, alkenes, alkynes, & cyclic
structures
 Nomenclature of Functional Groups

36. Alcohols
Simple alcohols are named as derivatives of the
parent alkane, using the suffix -ol, using the
following simple rules:
 Select the longest continuous carbon chain,
containing the hydroxyl group, and derive the parent
name by replacing the -e ending with -ol.
 Number the carbon chain, beginning at the end
nearest to the hydroxyl group.
 Number the substituents and write the name, listing
substituents alphabetically.

37. Alcohol Examples

38. Ether Nomenclature
 Simple ethers are named either by identifying
the two organic residues and adding the
word ether .
CH3—O—CH3
Dimethyl ether
CH3CH2OCH2CH3
Diethyl ether

39. Aldehydes Nomenclature
 Aldehydes are named by replacing the
terminal -e of the parent alkane with the
suffix -al
 The parent chain selected must contain the
carbonyl group.
 Number the carbon chain, beginning at the
end nearest to the carbonyl group.

40. Aldehyde Example
methanal
butanal
2-methyl butanal

41. Ketone Nomenclature
 The suffix for ketones is -one.
 The parent chain selected must contain the
carbonyl group.
 Number the carbon chain, beginning at the
end nearest to the carbonyl group.

42. Ketone Examples
3-pentanone propanone
3-methyl-2-butanone

43. Carboxylic Acid Nomenclature
Simple carboxylic acids are named as derivatives of
the parent alkane, using the suffix -oic acid
 Select the longest continuous carbon chain,
containing the carboxylic acid group, and derive the
parent name by replacing the -e ending with -oic
acid.
 Number the carbon chain, beginning at the end
nearest to the carboxylic acid group.
 Number the substituents and write the name, listing
substituents alphabetically.
 Carboxylic acid substituents attached to rings are
named using the suffix -carboxylic acid.

44. Carboxylic Acid Examples

45. Ester Nomenclature
 Esters are named by replacing the terminal of
end with the suffix -oate
 The parent chain selected must contain the
 Number the end of the carbon chain (after the
second O), and give it an –yl ending.
 Practice Problems

46. Amine Nomenclature
 RNH2 , R2NH, R3N
 In amines, a nitrogen is bonded to one, two
or three carbon atoms.
 Practice Problems

47. Functional Groups as Isomers
 Some functional groups can exist as isomers
of each other.
 Example: C4H8O2

48. Try the following: