1. What is organic chemistry
An organic compound
is a compound made from carbon atoms.
has one or more C atoms.
has many H atoms.
may also contain O, S, N, and halogens
Typical organic compounds
have covalent bonds.
have low melting points.
have low boiling points.
are flammable.
are soluble in nonpolar solvents.
are not soluble in water.
oil (organic) and water (inorganic)

2. Organic vs. Inorganic
Propane, C3H8, is an organic compound used as a fuel.
NaCl, salt, is an inorganic compound composed of Na+ and Cl- ions.

3. Recall carbon’s properties!
In organic compounds
carbon has 4 valence electrons and hydrogen has 1. •
•C • H •
to achieve an octet, C forms four bonds.
H H
 
H  C  H H C H
H H CH4 , methane
carbon atom with four single, covalent bonds, has a tetrahedral shape

4. Organic molecules have….
In organic molecules,
valence electrons are shared.
covalent bonds form between carbon atoms.
H H H H
• • • •
H  C  C  H H C C H
H H H H
ethane, CH3─CH3

5. What are alkanes?
Alkanes are written with structural formulas that are
expanded to show each bond.
condensed to show each carbon atom and its attached hydrogen atoms.
Expanded Condensed H
H C H CH4 , methane
In methane, CH4 the four valence electrons of carbon are shared with the single electrons of four hydrogen (H) atoms. Each pair of electrons is a single bond, which can be drawn as a line. When a structure is drawn to show each bond, it is called a complete structural formula.

6. Expanded vs condensed!
Condensed formulas are written for expanded structural formula by showing each carbon and the attached hydrogen atoms.
Expanded Condensed
H H H H
│ │ │ │
H─C ─C ─C ─C ─ H CH3─CH2─CH2─CH3

7. How to name alkanes? The names of alkanes
are determined by the IUPAC (International Union of Pure and Applied Chemistry) system.
end in –ane.
with 1-4 carbons in a chain use prefixes as follows.
Name # Carbons Structural Formula
Methane 1 CH4
Ethane CH3CH3
Propane CH3CH2CH3
Butane 4 CH3CH2CH2CH3
Pentane CH3CH2CH2CH2CH3
Hexane CH3CH2CH2CH2CH2CH3
Heptane CH3CH2CH2CH2CH2CH2CH3
Octane CH3CH2CH2CH2CH2CH2CH2CH3
Nonane CH3 CH2 CH2CH2CH2CH2CH2CH2CH3
Decane CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

8. Learning Check A. Write the condensed formula for: H H H H H
H C C C C C H
H H H H H
B. What is its molecular formula?
C. What is its name?
A. CH3─CH2─CH2─CH2─CH3
B. C5H12
C. pentane

9. Writing Structural Formulas
Carbon atoms in a chain
maintain tetrahedral shape.
are connected in a zig-zag pattern.
are drawn as 2-dimensional.
Ccan be written in several conformations.

10. Hexane has Six Carbon Atoms
is an alkane with six carbon atoms in a continuous chain.
has a “zig-zag” look because each carbon atom is at the center of a tetrahedron.
is represented by a ball-and-stick model as shown below.

11. What are cycloalkanes? Cycloalkanes are cyclic alkanes.
have two hydrogen atoms fewer than the open chain.
are named by using the prefix cyclo- before the name of the alkane chain with the same number of carbon atoms.

12. Learning check Name the following. A. CH3─CH2─CH2─CH3 B.
C. CH3─CH2─CH2─CH2─CH2─CH2─CH2─CH3 D.

13. Need to use substituent with alkanes
Isomers of Butane
have the same molecular formula.
have different atom arrangements.
of butane (C4H10) are a straight chain and a branched chain.
Alkyl groups are
alkanes that are missing one H.
substituents attached to carbon chains.
named with a –yl ending.
CH3 methyl
CH CH2 ethyl

14. Alkanes with substituents
CH3
CH3 CH CH methylpropane
methyl groups
CH CH3
CH3 CH CH2 CH CH ,4-dimethylpentane

15. Naming alkanes Give the name of CH3 CH3   CH3─CH─CH─CH3
 
CH3─CH─CH─CH3
STEP Name the longest continuous chain.
CH3 CH3
butane

16. Naming Alkanes Give the name of CH3 CH3   CH3─CH─CH─CH3
 
CH3─CH─CH─CH3
STEP Number chain CH3 CH3
 
STEP 3 Locate substituents and name.
2,3-dimethylbutane

17. Let’s practice again! STEP 1 Longest chain is pentane.
STEP Number chain from end nearest substituent.
Cl CH3
 
CH3─CH2─CH─CH─CH3
STEP 3 Locate substituents and name alphabetically.
3-chloro-2-methylpentane

18. Learning Check Give the IUPAC name for each of the following:
A CH CH3
| |
CH3─CH─CH2 ─CH─CH3
B Cl CH3
| |
CH3─CH2─CH─CH2─C─CH2─CH3 | Cl

19. Learning Check Draw the condensed structural formula for
2-bromo-1-chlorobutane.

20. Naming Cycloalkanes with Substituents
The name of a substituent is placed in front of the
cycloalkane name.
methylcyclobutane CH3
chlorocyclopentane Cl

21. Learning Check
Name each of the following.
CH3
CH2─ CH3 2.

22. Some Properties of Alkanes
Alkanes are
nonpolar.
insoluble in water.
less dense than water.
flammable in air.
Alkanes with 1-4 carbon atoms are
methane, ethane, propane, and butane.
gases at room temperature.
used as heating fuels.
Alkanes with 5-8 carbon atoms are
liquids at room temperature.
pentane, hexane, heptane, and octane.
very volatile.
used to make gasoline.
Alkanes with 9-17 carbon atoms
are liquids at room temperature
have higher boiling points.
are found in kerosene, diesel, and jet fuels
Alkanes with 18 or more carbon atoms
have high molar masses.
are waxy solids at room temperature.
used in waxy coatings of fruits and vegetables.

23. Reactions of alkanes: Combustion
In combustion reactions,
alkanes react with oxygen.
CO2, H2O and energy are produced.
Alkane + O CO2 + H2O + heat

24. Learning Check Write a balanced equation for the
complete combustion of propane
Unbalanced equation
C3H8 + O CO2 + H2O
Balance C
C3H8 + O CO2 + H2O
Balance H
C3H8 + O CO2 + 4H2O
Balance O
C3H8 + 5O CO2 + 4H2O (Balanced)

25. Other elements in organic compounds
In organic molecules,
carbon atoms bond
with four bonds.
mostly with H and other C atoms.
sometimes to O, N, S,
sometimes to halogens F, Cl, and Br.

26. What are functional groups?
Functional groups are
a characteristic feature of organic molecules that behave in a predictable way.
composed of an atom or group of atoms.
groups that replace a hydrogen atom in the corresponding alkane.
a way to classify families of organic compounds.