1. Organic Chemistry
Syed Arshad Mushtaq

2. Serendipity and scientific discoveries – PTFE and super glue.
ESSENTIAL IDEA
Organic chemistry focuses on the chemistry of compounds containing carbon.
NATURE OF SCIENCE (1.4)
Serendipity and scientific discoveries – PTFE and super glue.
NATURE OF SCIENCE (4.5)
Ethical implications – drugs, additives and pesticides can have harmful effects on both people and the environment.

3. INTERNATIONAL-MINDEDNESS
A small proportion of nations have control over the world’s oil resources. The interdependence of the countries that are net importers and those that are next exporters is an important factor in shaping global policies and economic developments. The octane rating (octane number) can be described as a standard measure of the performance of the fuel used in cars and aircraft. Octane ratings often vary quite widely regionally throughout the globe, and are complicated by the fact that different countries use different means of expressing the values.

4. THEORY OF KNOWLEDGE
The label “organic chemistry” originates from a misconception that a vital force was needed to explain the chemistry of life. Can you think of examples where vocabulary has developed from similar misunderstandings? Can and should language ever be controlled to eliminate such problems?

5. UNDERSTANDING/KEY IDEA 10.1.A
A homologous series is a series of compounds of the same family, with the same general formula, which differ from each other by a common structural unit.

6. HOMOLOGOUS SERIES
Definition – family of organic compounds which possesses certain common features.
Successive members differ by a –CH2 group.
Members of a series can be represented by the same general formula.
Members show a gradation in physical properties.
Members have similar chemical properties.

8. MEMBERS DIFFER BY –CH2
In a homologous series, as you change from one member to the next, the molecular mass increases by a fixed amount.
This fixed amount is due to the addition of successive –CH2 groups.
When you go from propane to butane, what changed?
You added one carbon to the series along with two hydrogen atoms.
This is typical of each homologous series.

9. MEMBERS REPRESENTED BY SAME GENERAL FORMULA
Alkanes and alkenes are represented by the formulas CnH2n+2 and CnH2n respectively.
A functional group is a small group of atoms attached to a carbon atom giving the compound characteristic properties.
Functional groups are shown in the general formulas.
Alcohols are represented by CnH2n+1OH or ROH where “R” is the parent hydrocarbon abbreviation.

10. MEMBERS SHOW A GRADATION OF PHYSICAL PROPERTIES
As successive members of a series differ by a –CH2 group, they have successively longer chains.
There is a gradual trend in the change of physical properties due to this change in molar mass.
Boiling point, density and viscosity are physical properties with predictable trends in homologous series.

11. MEMBERS SHOW SIMILAR CHEMICAL PROPERTIES.
Since members of a series have the same functional group, their members show similar chemical reactivity.
If we know the characteristic reactions of a functional group, we can predict the properties of all members of a series.

12. Examples of homologues series
Alcohol
Alkene
CH3OH
Methanol
C2H5OH
Ethanol
C3H7OH
Propanol
C4H9OH
Butanol
C5H11OH
Pentanol
C6H13OH
Hexanol
C2H4
Ethene
C3H6
Propene
C4H8
Butene
C5H10
Pentene
C6H12
Hexene

13. APPLICATION/SKILLS
Be able to explain the trends on boiling points of members of a homologous series.

14. BOILING POINT TRENDS
The boiling point is affected by the length of the carbon chain.
Boiling point increases with increasing carbon number.
This is caused by the increased number of temporary dipoles causing stronger van der Waal’s forces between molecules as their size increases.

15. The first four alkanes are gases at room temperature followed by the next four alkanes existing as liquids at room temp.
Methane has a boiling pt of -164°C and octane 125°C.
The increase is not linear, but steeper near the beginning because the smaller molecules are more affected by the addition of a –CH2.

16. APPLICATION/SKILLS
Be able to distinguish between empirical, molecular and structural formulas.

17. EMPIRICAL FORMULA
Definition – the simplest whole number ratio of the atoms a compound contains.
The formula can be derived from percentage composition data obtained from combustion analysis.
It is limited in its use as it does not tell us the actual number of atoms in the molecule.

18. MOLECULAR FORMULA
Definition – the actual number of atoms of each element present in the compound and is a multiple of the empirical formula.
It does not show us how the atoms are arranged in relation to each other and in space.
Properties of a compound are determined by not only the atoms, but by their arrangement in space so the molecular formula is limited in its value.

19. UNDERSTANDING/KEY IDEA 10.1.B
Structural formulas can be represented in full and condensed format.

20. STRUCTURAL FORMULA
A full structural formula shows us every bond and every atom.
H H
H - C – C – H
You must show all C’s and H’s and functional groups in a structural formula or you will not receive credit. Skeletal structures are not acceptable.

21. CONDENSED STRUCTURAL FORMULA
A condensed structural formula omits bonds where they can be assumed and groups atoms together.
CH3CH3 or CH3COOH

22. STEREOCHEMICAL FORMULA
Attempts to show the positions of atoms in three dimensions.
A bond sticking out of the front of the page is represented by a solid triangular wedge.
A bond sticking out of the back of the page is dotted line.
Four bonds are tetrahedral with bond angles of 109.5°.
Three bonds are trigonal planar with 120°.

23. Understanding/Key idea
Structural isomers are compounds with the same molecular formula but different arrangements of atoms

24. Structural Isomers
Structural isomers are different compounds with the same molecular formula but different arrangements of atoms
Butane C4H10

25. Try Structural formula for
C5H12
C5H10 ( hint one double)

26. UNDERSTANDING/KEY IDEA 10.1.C
Saturated compounds contain single bonds only and unsaturated compounds contain double and triple bonds.

27. GUIDANCE
Be able to apply the IUPAC rules in nomenclature for the following: 1. non-cyclic alkanes and halogenoalkanes up to halohexanes 2. alkenes up to hexene 3. alkynes up to hexyne

28. GUIDANCE
4. Compounds up to 6 carbon atoms containing only one of the classes of functional groups: alcohols, ethers, aldehydes, halogenoalkanes, ketones, esters, and carboxylic acids, amines, amides, nitriles and arenes.

29. Learning out come
Identify the following different classes: alkanes, alkenes, alkynes, halogenoalkanes, alcohols, ethers, aldehydes, ketones, esters, carboxylic acids, amines, amides, nitriles and arenes
Identify typical functional groups in molecules e.g. phenyl, hydroxyl, carbonyl, carboxyl, carboxamide, aldehyde, ester, ether, amine, nitrile, alkyl, alkenyl and alkynyl.
It’s Family thing

30. UNDERSTANDING/KEY IDEA 10.1.D
Functional groups are the reactive parts of molecules.
Definition : An atom or group of atoms that give characteristic properties to an organic compound

31. Picture Source https://www.pinterest.com/pin/199073245998510273/

32. Nitrile
Example
Butanenitrile

33. Identify functional groups
Alcohol
Ether

34. Identify functional groups in Acetylsalicylic acid (Aspirin )
Carboxylic acid group
Ester Group

35. A B C D

36. Nomenclature
System of Naming

37. Learning outcomes Should be able to name
Non-cyclic alkanes and halogenoalkanes containing up to six carbon atoms.
Alkenes up to hexene and alkynes up to hexyne.
Compounds up to six carbon atoms (in the basic chain for nomenclature purposes) containing only one of the following functional groups: hydroxyl, ether, aldehyde, halogenoalkane, carbonyl, ester and carboxyl.

38. Naming Organic Compounds
Originally compounds were named based on their source or use
Many organic compounds were given common names which are still in use
However many ambiguities resulted
With the large number of organic compounds, a method for systematically naming them is very important 38

39. IUPAC Names
The International Union of Pure and Applied Chemists (IUPAC) developed a system for naming organic compounds.
This system eliminated many of the ambiguities that plagued earlier naming systems
Common names for many substances are still widely used 39

40. Naming Hydrocarbons using the IUPAC System
A series of prefixes are used to designate the number of carbon atoms in a carbon chain
meth
1 C
hex
6 C
eth
2 C
hept
7 C
prop
3 C
oct
8 C
but
4 C
non
9 C
pent
5 C
dec
10 C 40

41. Naming Alkanes
For straight chain hydrocarbons. The prefix indicates the number of carbon atoms.
The suffix ane is added to designate that the compound is an alkane 41

42. Naming Alkanes with branched chains
For branched chain hydrocarbons, identify the longest consecutive (straight) chain first. Then name the side chains or branches.
The name of the branches end in “yl” and go before the name of the straight chain
-methylpropane
methyl butane
dimethyl propane
Video 42

43. 2,2 dimethyl hexane Practice 2- methyl Hexane 2- methyl
2-methyl, 2-methyl hexane
Sounds redundant
2,2 dimethyl hexane

44. Practice H C
2-methyl hexane
2,3-Dimethyl hexane

45. Is your arm sore yet?
Are you sick to death of writing all those carbons?
Even worse, are you sick of writing all those Hydrogens?
How about this…

46. Shorthand notation C H
Keep in mind that we have been ignoring the hydrogens for a long time.
Our names have been based entirely on the positioning of the carbons.
Each end and each “point” represents a carbon atom. The hydrogen atoms are assumed to be there.
So lets now ignore the hydrogens completely!

47. Is it that easy? H C C H

48. Alkenes Alkenes have one (or more) carbon to carbon double bonds
When there are 4 or more carbon atoms in a chain, the location of the double bond is indicated by a number.
Numbering the location of the double bond(s) takes precedence over the location of side chains
but-1-ene but-2-ene methylpropene 48

49. Practice H C
hex-2-ene H C
but-1-ene C H
3 methyl pent-1-ene

50. How about in Shorthand? pent-2-ene 2,3-dimethylbut-2-ene,
Notice the two lines means the double bond is there!
3-methylpent-1-ene,
pent-2-ene
2,3-dimethylbut-2-ene,

51. Practice! Methyl propene 2,4-dimethylpent-2-ene
3-ethyl-2,4,4-trimethylpent-1-ene

52. Geometric Isomers in alkenes
A cis isomer is one in which the substituents are on the same side of the C=C
cis-but-2-ene
A trans isomer is one in which the substituents are on the opposite sides of the C=C
trans-but-2-ene 52

53. cis isomers have higher boiling point than trans.

54. trans pent-2-ene 2,3-dimethylbut-2-ene
does not have geometrical isomers because there are two identical groups attached to the same carbon of the double bond.

55. Alkynes Alkynes have one (or more) carbon to carbon triple bonds
Since there are fewer hydrogen atoms in alkynes as a result of the triple bond, alkynes like alkenes are referred to as unsaturated. 55

56. Alkyne Structures
Like alkanes and alkenes, alkynes can have branched or consecutive chains. In the larger alkenes there are also multiple locations for the C=C. Multiple structural isomers are possible. The branch cannot originate on one of the carbons making up the triple bond
Branched chain. The triple bond can occur in one of the branches but branches cannot be attached to any carbon in the triple bond
Straight chain. The triple bond is between the first and second carbon
Straight chain. The triple bond is between the second and third carbon 56

57. Practice Draw the structure of the followings
2-Methyl pent-1-yne ,4-Dimethyl hex-2-yne

58. Practice

59. This one
Pentyne

60. For more lessons, visit www.chalkbored.com
Head-to-Head Naming
Draw a hydrocarbon molecule on a sheet. Have a friend draw a hydrocarbon molecule on their sheet. Exchange papers and see who can correctly name the other persons hydrocarbon first. As always, no wagering please.
For more lessons, visit

61. Halogenoalkane
Fluorides, Chlorides, Bromides, and Iodides attached to Alkyl group
Simply name the molecule as normal but add the prefix Fluoro, Chloro, Bromo, or Iodo as necessary

62. Halogenoalkane 1-bromopropane prefixes = “fluoro, chloro, bromo, iodo”
2 chlorobutane
1,2 diiodoethane
cis 1,2difluroethene
Trans 1,2 difluoroethene
1,1,2 trifluorothene
prefixes = “fluoro, chloro, bromo, iodo” 62

63. Halogenoalkane Cl
2, 3 dichlorohexane I
3, 3 diiodopent-1-ene

64. Worksheets
Timer

65. TOK Connection

66. Functional Groups Halogenoalkanes Alcohols Ethers Aldehydes Ketones
Carboxylic Acids
Esters
Amines
R-F, R-Cl, R-Br, R-I
R-OH
R-O-R
R-COH
R-CO-R
R-COOH
R-COO-R
R-NH2

67. Naming Compounds With Functional Groups
Various functional groups have unique suffixes that designate the functional group.
The functional group takes precedence in numbering the carbon chain.
Branches to the carbon chain are named in the usual manner.
alcohols
“ol”
Amides
“amide”
Aldehydes
“al”
Amines
“amine” or amino as a prefix
Ketones
“one”
Ethers
Ethoxy as prefix
Acids
“oic”
halohydrocarbons
Fluoro, bromo, chloro or iodo
Esters
“oate” 67

68. Alcohols
R-OH
Name like normal except add an –ol suffix

69. Alcohols
Suffix = “ol”
Propan-1-ol
Propan-2-ol
2-methyl propan-2-ol 69

70. Alcohols OH OH
Propan-2-ol
cyclobutanol OH C H
ethanol

71. Ethers
R-O-R
Name two “R” groups with –yl endings
End name in ether

72. Ethers Suffix = “oxy”on first branch Ethoxyethane (diethylether)
Ethoxybutane
(ethylbutyl ether) 72

73. Ethers O O Ethyl methyl ether (Methoxyethane) Dimethyl ether
(Methoxymethane) O
Ethyl methyl ether
(Methoxyethane)

74. Aldehyde
R-CHO
This is a carbon to oxygen double bond with a hydrogen at the end.
Name as normal except use a “-al” suffix

75. Aldehydes and Alkanals
Suffix = “al”
Propanal
Note that the aldeyhde group is always on an end carbon or carbon 1 75

76. Aldehydes C H O
butanal C H Cl O
3,3 dichloropentanal

77. Ketones or Alkanones Suffix = “one” Propanone (also known as acetone)
Butanone
(also known as ethyl methyl ketone)
Pentan-2-one
(note the number is necessary
Because the C=O could be on carbon
2 or carbon 3) 77

78. Ketones C H O C H H
pentan-2-one C H C H O
hexan-2-one

79. Carboxylic Acids R-COOH or R-CO2H
This is a carbon to oxygen double bond with the same carbon single-bonded to an OH group.
Name as normal except give it the suffix “-anoic acid”.
HC2H3O2

80. Carboxylic Acids Suffix = “oic” Butanoic acid
Note that the acid group (called a “carboxyl”) is always on an end carbon or carbon 1 80

81. Carboxylic Acids Butanoic acid 3-Fluoropropanoic acid C H OH O C H F O

82. Esters
R-COO-R
This is a carbon to oxygen double bond with a carbon to oxygen single bonded to another single bonded carbon
Name by given secondary branch “-yl” suffix and main branch “-anoate” suffix.

83. Esters Esters Suffix = “oate” Ethyl butanoate Butyl ethanoate
There are two branches. The branch with the carbonyl gets the suffix 83

84. Esters methyl pentanoate Methyl Pentanoate Secondary Branch
Main Branch C H O
methyl
pentanoate
Methyl Pentanoate

85. Esters C H O
Butyl propanoate C H O
Methyl hexanoate

86. Amines R-NH2 Name the “R” group or groups with “-yl” endings
Add the word “amine”

87. Amines Suffix = “amine” Or prefix = “amino”
Propylamine or 1-aminopropane
2-propylamine or 2-aminopropane
2-methyl-2-propylamine or
2-methyl -2- aminopropane 87

88. Amines C H N
Methyl amine C H N
Dimethyl amine

89. Amides Suffix = “amide” butanamide
Note that the amide group is always on an end carbon or carbon 1 89

90. Summary Cl R Halide OH R Alcohol R O Ether H R C Aldehyde O R C Ketone
Carboxylic Acid O O R C
Ester
NH2 R
Amine

91. Summary Alkanes - “-ane” Alkenes = “-ene” Alkynes “-yne” Halides
Alcohols
Ethers
Aldehydes
Ketones
Carboxylic Acids
Esters
Amines
- “-ane”
= “-ene”
“-yne”
R-X “-o”
R-OH “-ol”
R-O-R “-yl ether”
R-COH “-al”
R-CO-R “-one”
R-COOH “-anoic acid”
R-COO-R “-yl” “-anoate”
R-NH2 “-yl amine”

92. Can You Do This? YES! It takes: Memorization Practice And, oh yes…

93. Classifications Primary Secondary and tertiary
Halogenoalkanes , Alcohols and Amines

94. Learning Objectives
Distinguish between primary secondary and tertiary Alcohols.
Distinguish between primary secondary and tertiary halogenoalkanes.
Distinguish between primary secondary and tertiary Amines.

95. Classifications of Alcohol
Learning Objectives
Distinguish between primary secondary and tertiary Alcohols

96. Primary, secondary and Tertiary carbon
Primary = a carbon attached to only ONE other carbon
Secondary  = a carbon attached to only TWO other carbons
Tertiary = a carbon attached to THREE other carbons

97. Primary Alcohols
A primary alcohol has only one carbon atom attached 3

98. Secondary Alcohols
A secondary alcohol has 2 carbon chains attached to the group on which the –OH resides 4

99. Tertiary Alcohols 5

100. Is cholesterol a primary, secondary or tertiary alcohol?

101. Classification of Halogenoalkanes
Learning Objectives
Distinguish between primary secondary and tertiary Halogenoalkanes

102. Primary Halogenoalkane
In a primary (1°) halogenoalkane, the carbon which carries the halogen atom is only attached to one other alkyl group.
Some examples of primary halogenoalkanes include:

103. Secondary halogenoalkanes
In a secondary (2°) halogenoalkane, the carbon with the halogen attached is joined directly to two other alkyl groups, which may be the same or different.
Examples:

104. Tertiary halogenoalkanes
In a tertiary (3°) halogenoalkane, the carbon atom holding the halogen is attached directly to three alkyl groups, which may be any combination of same or different.
Examples:

105. Practice

106. Classification of Amines
Learning Objectives
Distinguish between primary secondary and tertiary Amines

107. Primary amines
In primary amines, only one of the hydrogen atoms in the ammonia molecule has been replaced. That means that the formula of the primary amine will be RNH2 where "R" is an alkyl group.
Examples include:

108. Secondary amines
In a secondary amine, two of the hydrogens in an ammonia molecule have been replaced by hydrocarbon groups. At this level, you are only likely to come across simple ones where both of the hydrocarbon groups are alkyl groups and both are the same.
For example:

109. Tertiary amines
In a tertiary amine, all of the hydrogens in an ammonia molecule have been replaced by hydrocarbon groups. Again, you are only likely to come across simple ones where all three of the hydrocarbon groups are alkyl groups and all three are the same.
The naming is similar to secondary amines. For example:

110. Practice

111. Structure of Benzene Learning outcome
Benzene is an aromatic, unsaturated hydrocarbon represented by  .
Use physical and chemical evidence to discuss the structure of benzene.

112. The Kekulé structure for benzene, C6H6
Kekulé was the first to suggest a sensible structure for benzene. The carbons are arranged in a hexagon, and he suggested alternating double and single bonds between them. Each carbon atom has a hydrogen attached to it.
Kekule’dream

113. This diagram is often simplified by leaving out all the carbon and hydrogen atoms!

114. Problems with the Kekulé structure
Problems with the chemistry
Because of the three double bonds, you might expect benzene to have reactions like ethene.
Ethene undergoes addition reactions in which one of the two bonds joining the carbon atoms breaks, and the electrons are used to bond with additional atoms.
Benzene rarely does this. Instead, it usually undergoes substitution reactions in which one of the hydrogen atoms is replaced by something new

115. Problems with the Kekulé structure
Problems with the shape
Benzene is a planar molecule (all the atoms lie in one plane), and that would also be true of the Kekulé structure. The problem is that C-C single and double bonds are different lengths.
C-C nm C=C nm
That would mean that the hexagon would be irregular if it had the Kekulé structure, with alternating shorter and longer sides.
In real benzene all the bonds are exactly the same - intermediate in length between C-C and C=C at nm. Real benzene is a perfectly regular hexagon

116. Problems with the Kekulé structure
Problems with the stability of benzene
Real benzene is a lot more stable than the Kekulé structure would give it credit for. Every time you do a thermochemistry calculation based on the Kekulé structure, you get an answer which is wrong by about 150 kJ mol-1. This is most easily shown using enthalpy changes of hydrogenation.

117. Molecular Structure of benzene
Each of the six carbon atoms is sp2 hybridized forming 3 sigma bonds with angles of 120, making a planar shape.
This leaves one unhybridized p electron on each carbon atom with its dumb-bell shape perpendicular to the plane of the ring.

118. The p orbitals effectively overlap in both directions spreading themselves out evenly to be shared by all 6 carbon atoms.
This forms a delocalized pi electron cloud in which electron density is concentrated in two donut-shaped rings above and below the plane of the ring.
This very stable arrangement lowers the internal energy of the molecule.

119. Video
Orbital Structure

121. The symbol for benzene
Although you will still come across the Kekulé structure for benzene, for most purposes we use the structure on the right.
The hexagon shows the ring of six carbon atoms, each of which has one hydrogen attached.
The circle represents the delocalised electrons. It is essential that you include the circle. If you miss it out, you are drawing cyclohexane and not benzene.

122. Theory of Knowledge
Kekule claimed that the inspiration for the cyclic structure of benzene came from a dream. What role to the less analytical ways of knowledge play in the acquisition of scientific knowledge?

123. Citation