1. Chapter 10 Introduction to Organic Chemistry: Alkanes
10.1
Organic Compounds

2. 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.

3. Organic Compounds 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)

4. 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.
Why is propane organic,
but NaCl is not?

5. Comparing Organic and Inorganic Compounds

6. Writing Formulas for Alkanes
In organic compounds,
carbon has 4 valence electrons and hydrogen has 1. •
• C • H •
carbon achieves an octet by forming four bonds.
H H
 
H  C  H H C H
H H CH4, methane

7. Organic Chemistry’s Golden Rule:
Carbon always forms 4 bonds. 7

8. Tetrahedral Structure of Carbon
VSEPR theory predicts that a carbon atom with four single, covalent bonds has a tetrahedral shape.

9. Organic Molecules 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

10. Tetrahedral Structure of Carbon
In molecules with two or more carbon atoms, each carbon atom with four single bonds has a tetrahedral shape.

11. Structural Formulas
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.

12. Expanded and Condensed Structures
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13. Structural Formulas
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

14. Types of formulas and models used to represent organic molecules
Types of formulas and models used to represent organic molecules. Each diagram is a representation of a propane molecule. 14 14

15. Modified Skeleton formula
Structural formula
Skeleton formula
Modified Skeleton formula
Remove H’s
Remove H bonds
Remove C’s
Line structure 15

16. This is an example of how to change a condensed formula
into a line structure. 16 16

17. Names of 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 Condensed Structural ______Formula_______
Methane 1 CH4
Ethane 2 CH3―CH3
Propane 3 CH3―CH2―CH3
Butane 4 CH3―CH2―CH2―CH3

18. Names of Alkanes
Alkanes with 5-10 carbon atoms in a chain use Greek prefixes.
Name # Carbons Structural Formula
Pentane CH3CH2CH2CH2CH3
Hexane CH3CH2CH2CH2CH2CH3
Heptane CH3CH2CH2CH2CH2CH2CH3
Octane CH3CH2CH2CH2CH2CH2CH2CH3
Nonane CH3 CH2 CH2CH2CH2CH2CH2CH2CH3
Decane CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

19. Writing Structural Formulas
Carbon atoms in a chain
maintain tetrahedral shape.
are connected in a zigzag pattern.
are drawn as 2-dimensional.
can be written in several conformations.

20. Some Structures for Butane
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21. Hexane Has Six Carbon Atoms
is an alkane with six carbon atoms in a continuous chain.
has a “zigzag” look because each carbon atom is at the center of a tetrahedron.
is represented by a ball-and-stick model as shown below.

22. 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.

23. Cycloalkanes
The structural formulas of cycloalkanes are usually represented by geometric figures.

24. More Cycloalkanes

25. Learning Check Name the following. A. CH3─CH2─CH2─CH3 B.
C. CH3─CH2─CH2─CH2─CH2─CH2─CH2─CH3 D.

26. Chapter 10 Introduction to Organic Chemistry: Alkanes
10.3
Alkanes with Substituents

27. Isomers of Butane Isomers have the same molecular formula.
have different atom arrangements.
of butane (C4H10) are a straight chain and a branched chain.

28. Alkyl groups Alkyl groups are alkanes that are missing one H.
substituents attached to carbon chains.
named with a –yl ending.
CH3 methyl
CH3 CH2 ethyl

29. Naming Substituents In the IUPAC system,
a carbon branch is named as an alkyl group.
halogen atoms are named as halo.

30. Guide to Naming Alkanes

31. Alkanes with Substituents
CH3
CH3 CH CH methylpropane
methyl groups
CH CH3
CH3 CH CH2 CH CH ,4-dimethylpentane

32. Naming Alkanes Give the name of CH3 CH3   CH3─CH─CH─CH3
 
CH3─CH─CH─CH3
STEP 1: Name the longest continuous chain.
CH3 CH3
butane

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

34. Learning Check
Write the name of
Cl CH3
 
CH3─CH2─CH─CH─CH3

35. 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

36. Guide to Drawing Alkane Formulas

37. Learning Check Draw the condensed structural formula for
3-bromo-1-chlorobutane.

38. Solution 3-bromo-1-chlorobutane
STEP 1: Longest chain has 4 carbon atoms.
C─C─C─C
STEP 2: Number chain and add substituents. Br 
C ─ C ─ C ─ C ─ Cl
STEP 3: Add hydrogen to complete 4 bonds to each C.
CH3─CH─CH2─CH2─Cl

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

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

41. Alkyl Halides
Alkyl halides are organohalogens that have the halogen atom attached to an alkyl group.
They are represented by R–X

42. Naming Alkyl Halides CH3Br CH3CHBrCH2Br bromomethane (methyl bromide)
1,2-dibromopropane
CHCl3
trichloromethane
(chloroform)
CH2Cl2
dichloromethane (methylene chloride)
CCl4
tetrachloromethane
(carbon tetrachloride)

43. Chapter 10 Introduction to Organic Chemistry: Alkanes
10.4
Properties of Alkanes

44. Some Properties of Alkanes
Alkanes are
nonpolar.
insoluble in water.
less dense than water.
flammable in air.

45. Some Properties of Alkanes
Alkanes with 1-4 carbon atoms are
methane, ethane, propane, and butane.
gases at room temperature.
used as heating fuels.

46. Some Properties of Alkanes
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.

47. Some Properties of Alkanes
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.

48. Combustion In combustion reactions, alkanes react with oxygen.
CO2, H2O, and energy are produced.
Alkane + O CO2 + H2O + heat
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49. Chapter 10 Introduction to Organic Chemistry: Alkanes
10.5
Functional Groups

50. 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.
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51. 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.

52. Alkenes, Alkynes, and Aromatic Compounds
Alkenes contain a double bond between adjacent carbon atoms.
Alkynes contain a triple bond.
Aromatic compounds contain a ring of six carbon atoms called benzene.
An alkene
(olefins)
An alkyne
(acetylenes)
An aromatic
(benzenes)

53. Comparing Alkenes, Alkynes, and Aromatic Compounds

54. Alcohols and Ethers
An alcohol contains the hydroxyl (-OH) functional group.
A thiol contains the thiol (-SH) functional group.
An ether contains an oxygen atom bonded to two carbon atoms.

55. Aldehydes and Ketones
An aldehyde contains a carbonyl group (C=O), which is a carbon atom with a double bond to an oxygen atom. The carbonyl is attached to a hydrogen.
In a ketone, the carbon of the carbonyl group (C=O) is attached to two carbon atoms.

56. Carboxylic Acids and Esters
Carboxylic acids contain the carboxyl group, which is a carbonyl group attached to a hydroxyl group. O ║
— C—OH
An ester contains the carboxyl group between carbon atoms.

57. Amines and Amides In amines, the functional group is a nitrogen atom.|
—N —
In amides, the hydroxyl group of a carboxylic acid is replaced by a nitrogen group.
Amines
An amide

58. Summary of Functional Groups