1. Topic 10 – Organic Chemistry
Fundamentals of
Organic Chemistry 1

2. Organic Chemistry What do you know about organic chemistry? Discussion2

3. Organic Chemistry
Organic Chemistry – the study of carbon –based compounds.
Why carbon?
Can bond up to four times.
Can undergo catenation (create long chains of itself)
Can form straight-chain, branched, or cyclical structures. 3

4. General Formula – CnH2n+2
Classification
Homologous Series – group of compounds with the same general formula, structure, physical and chemical properties.
Examples:
ALKANE
METHANE
ETHANE
PROPANE
BUTANE
FORMULA
CH4
C2H6
C3H8
C4H10
General Formula – CnH2n+2
*** Alkanes only have single C-C bonds and differ by the
number of methylene groups.
Alkenes have C=C bonds, and alkynes have C C bonds.
Homologous series can also contain functional groups. 4

5. Exercise Using the molecular model kits, build a molecule for:
CH4
C2H6
C3H8
C4H10
C5H12
C6H14
Draw each of the molecules.

6. Physical Properties Properties change as more atoms are added.
Example: boiling point goes up with every additional carbon due to increased intermolecular forces.
Distillation can be used to separate compounds based on their boiling points. 6

7. Intermolecular Forces
There are three kinds of intermolecular forces that occur between molecules. They are listed here in order of increasing strength:
London dispersion forces (between non-polar molecules)
Dipole–dipole forces (between polar molecules)
Hydrogen bonding (between hydrogen of one polar molecule and O, N, F of another polar molecule)
London forces and dipole-dipole forces are collectively known as “van der Waal forces.”

8. London Dispersion Forces
Instantaneous dipole that occurs accidentally in a given atom induces a similar dipole in a neighboring atom.
Significant in large atoms/molecules.
Occurs in all molecules, including nonpolar ones.

9. London Forces
The magnitude of London forces are affected by three factors.
Number of electrons
Size (volume) of the
electron cloud
Shapes of the molecules

10. Dipole–Dipole Attraction
Polar molecules contain different
atoms which have different
electronegativities and can be
thought to be like a small bar
magnet. Oppositely charged ends attract and like ends repel. Molecules organize themselves to maximize the attractive forces
and minimize repulsive forces
giving molecules unique shapes.

11. Hydrogen Bonding in Water
Blue dotted lines are the intermolecular forces between the water molecules.

12. Homework
Complete Structural Formula Worksheet

13. Think, Pair, and Share
Discuss and determine how you think these intermolecular forces will affect the physical properties (melting point, boiling point, vapor pressure) of the molecules you built in the previous exercise:
CH4
C2H6
C3H8
C4H10
C5H12
C6H14

14. Physical Properties
1414

15. Physical Properties
This trend in boiling point results from increasingly strong London forces as the carbon chain becomes longer. Fractional distillation is a physical separation process that uses differences in boiling points to separate the mixture into fractions of similar boiling point. 15

16. Chemical Formulae Many ways to represent an organic compound:
Lewis dot structure
Empirical formula
Molecular formula
Structural formula
Full – shows all atoms and bonds
Condensed – shows all atoms, no bonds
Skeletal – lines, ends and corners are carbon atoms, only functional groups are identified.
CH3CH2COOH 16

17. Nomenclature
The International Union of Pure and Applied Chemistry (IUPAC) is the world authority on chemical nomenclature. The name of a chemical substance needs to provide enough information to identify the class of compound from which the chemical is derived, including any substituents and functional groups present. 17

18. (longest carbon chain)
IUPAC Nomenclature
Step 1 – Identify longest carbon chain
Step 2 – Determine if there are any branches
Step 3 – Number branches with lowest carbon
Step 4 – Arrange branches alphabetically
Step 5 – Use commas to separate numbers
Step 6 – Use hyphen to separate numbers and letters
Step 7 – Use multipliers if multiple of one branch is present
Step 8 – Successive words merge together
Prefixes
Parent Chain
Suffix
Principal Group
(alphabetical order)
(longest carbon chain)
(-ane, -ene, -yne)
(functional groups) 18

19. IUPAC Nomenclature Parent Chain meth - 1 Branch Names eth - 2
pro - 3
bu - 4
pent - 5
hex - 6
Branch Names
methyl - CH3
ethyl - CH2CH3
propyl - CH2CH2CH3
butyl - CH2CH2CH2CH3
Example:
3-ethyl-2-methylhexane
6 carbons is the longest chain (hexane)
2 branches (methyl and ethyl)
Lowest numbers are 2, 3 19

20. IUPAC Nomenclature Numbers Structural Isomers mono - 1 di - 2 cis-
tri - 3
tetra - 4
penta - 5
Structural Isomers
cis-
trans-
C = C Cl H
C = C Cl H
Example:
3-ethyl-2-methylhexane
6 carbons is the longest chain (hexane)
2 branches (methyl and ethyl)
Lowest numbers are 2, 3 20

21. 5-ethyl-2,3,3-trimethylheptane
Nomenclature
5-ethyl-2,3,3-trimethylheptane 21

22. Nomenclature
Draw the structural formula for C2H4O. 22

23. Nomenclature Draw the structural formula for C2H4O. O H ̶ C ̶ C ̶ H H
ethanal 23

24. Nomenclature Hydrocarbons Saturated – all C-C single bonds
Unsaturated – some C=C and C C bonds
Can have cyclo (all C-C) and aromatic (C=C) rings
Functional groups:
Take priority in naming
Carbon number is lowest on functional groups 24

25. Question
Predict the order of the boiling points for three isomers of pentane below.
Look them up to see if you
are right.
Using IUPAC nomenclature, name each of them.

26. Nomenclature PracticeHO Cl 26

27. Nomenclature PracticeHO
but-2-ene
but-1-yne Cl
butan-2-ol
4-methylpent-2-yne
2,3-dichloro-4,5-dimethylhexane
1,3-dimethylcyclopentane
buta-1,3-diene 27

28. Nomenclature PracticeOH O 28

29. Nomenclature Practice
propanone
(ketone)
n-butanal
(aldehyde) O OH O
butanoic acid
(carboxylic acid)
methyl propanoate
(ester) 29

30. Your Turn
Draw the structural formula for C4H8O. 30

31. Your Turn
Draw full structural, condensed structural and skeletal formulas for at least 5 of the C4H8O compounds (no cyclic ones) 31

32. Your Turn
Draw the structural formula for C4H8O. 32

33. Classifying Molecules
Saturated hydrocarbons – organic compounds consisting of carbon and hydrogen atoms only. Carbon-carbon bonds are single bonds. Mostly alkanes, which are aliphatic or straight-chain compounds.
Unsaturated hydrocarbons – contain double and/or triple carbon-carbon bonds.
Natural compounds – found in plants and animals – synthesized by organisms.
Synthetic compounds – mostly man-made compounds. 33

34. Propane CH3CH2CH3 Alkane Propan-2-ol CH3CH(OH)CH3 Alcohol Propanal
NAME
FULL
CONDENSED
SKELETAL
SERIES
Propane
CH3CH2CH3
Alkane
Propan-2-ol
CH3CH(OH)CH3
Alcohol
Propanal
CH3CH2CHO
Aldehyde
Propanone
CH3C(O)CH3
Ketone
Propanoic acid
CH3CH2COOH
Carboxylic acid
Propene
CH3CHCH2
Alkene
3434

35. Functional Groups Functional Group Name Group double bond RCOOR’
triple bond
R ̶ O ̶ R’
ROH
RNH2
RNHR
RN[R’]R”
RCHO
RCONH2
RCOR’
RCN
RCOOH
R ̶

36. Classifying Molecules
Aliphatic compounds – contain straight-chain carbon-carbon bonds.
Alkanes – saturated hydrocarbon containing only carbon-carbon single-bonds
Alkene – unsaturated hydrocarbon containing carbon-carbon double-bond(s)
Alkynes - unsaturated hydrocarbon containing carbon-carbon triple-bond(s)
Halide or Halogenoalkane – hydrocarbon containing halogen(s) substituted for hydrogen(s)
Alcohol – hydrocarbon containing hydroxyl group(s) (-OH ̶ ) substituted for hydrogen(s)
Aldehyde – hydrocarbon containing carbon-oxygen double-bonds on primary carbon
Ketones – hydrocarbon containing carbon-oxygen double-bonds on secondary carbon
Carboxylic acid – hydrocarbon containing a single primary carbon with a carbon-oxygen double-bond AND a carbon-hydroxyl single-bond 36

37. Classifying Molecules
Cyclic compounds – organic molecules that contain carbon-carbon rings OR OR
Aromatic compounds – organic molecules that contain benzene rings OR OR
called phenol group in a compound
can hydrogenate the double bonds using a catalyst 37

38. Homework
Complete the IUPAC Nomenclature Worksheet