1. Chapter 10 Introduction to Organic Chemistry: Alkanes
10.1
Organic Compounds
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Publishing as Benjamin Cummings

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
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6. Learning Check
Identify each characteristic as most typical of compounds
that are 1) inorganic 2) organic.
A. has a high melting point
B. is not soluble in water
C. has a formula CH3─CH2─CH3
D. has a formula MgCl2
E. burns easily in air
F. has covalent bonds

7. Solution Identify each characteristic as most typical of compounds
that are 1) inorganic 2) organic.
1 A. has a high melting point
2 B. is not soluble in water
2 C. has a formula CH3─CH2─CH3
1 D. has a formula MgCl2
2 E. burns easily in air
2 F. has covalent bonds

8. Writing Formulas for Alkanes
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

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

10. 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

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

12. Chapter 10 Introduction to Organic Chemistry: Alkanes
10.2
Alkanes
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Publishing as Benjamin Cummings

13. 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.

14. Expanded and Condensed Structures

15. 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

16. 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 Structural Formula
Methane 1 CH4
Ethane 2 CH3CH3
Propane 3 CH3CH2CH3
Butane 4 CH3CH2CH2CH3

17. 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 10 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

18. 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?

19. Solution
A. CH3─CH2─CH2─CH2─CH3
B. C5H12
C. pentane

20. 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.

21. Some Structures for Butane

22. 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.

23. Learning Check Write the condensed structural formula for A. ethane.
B. heptane.

24. Solution Write the condensed structural formula for A. ethane CH3─CH3
B. heptane CH3─CH2─CH2─CH2─CH2─CH2─CH3

25. 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.

26. Cycloalkanes The structural formulas of cycloalkanes are usually
represented by geometric figures,
Cyclopropane CH2
CH CH2
Cyclobutane CH CH2
CH CH2

27. More Cycloalkanes
Cyclopentane CH2
CH CH2
CH CH2
Cyclohexane
CH2

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

29. Solution Name the following: A. CH3─CH2─CH2─CH3 butane B. cyclopropane
C. CH3─CH2─CH2─CH2─CH2─CH2─CH2─CH3 octane D.
cyclohexane

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

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

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

33. Naming Substituents In the IUPAC system,
TABLE 10.6
In the IUPAC system,
a carbon branch is named as an alkyl group.
halogen atoms are named as halo.

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

35. 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

36. 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

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

38. Solution 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

39. 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

40. Solution A. CH3 CH3 | | CH3─CH─CH2 ─CH─CH3 2,4-dimethylpentane
| |
CH3─CH─CH2 ─CH─CH ,4-dimethylpentane
B Cl CH more substituents = C3
CH3─CH2─CH─CH2─C─CH2─CH3 | Cl
3,5-dichloro-3-methylheptane

41. Learning Check Draw the condensed structural formula for
2-bromo-4-chlorobutane.

42. Solution 2-bromo-4-chlorobutane
STEP Longest chain has 4 carbon atoms.
C─C─C─C
STEP 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

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

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

45. Solution Name each of the following. 1. methylcyclopropane
2. ethylcyclohexane

46. Chapter 10 Introduction to Organic Chemistry: Alkanes
10.4
Properties of Alkanes
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Publishing as Benjamin Cummings

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

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

49. 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.

50. 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.

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

52. Learning Check Write a balanced equation for the
complete combustion of propane.

53. Solution Unbalanced equation C3H8 + O2 CO2 + H2O Balance C
Balance H
C3H8 + O CO2 + 4H2O
Balance O
C3H8 + 5O CO2 + 4H2O (Balanced)
To balance the atoms in the formula C3H8, we place a coefficient of 3 in front of CO2 and a coefficient of 4 in front of H2O. The total O in the products is 10 O (6 O in 3CO2 and 4 O in 4 H2O). To balance the 10 O, a coefficient of 5 is placed in front of the O2.

54. Chapter 10 Introduction to Organic Chemistry: Alkanes
10.5
Functional Groups
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Publishing as Benjamin Cummings

55. 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.

56. 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.

57. Alkenes and Alkynes
Alkenes contain a double bond between adjacent carbon atoms.
Alkynes contain a triple bond.
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58. Alcohols and Ethers
An alcohol contains the hydroxyl (-OH) functional group.
In an ether, an oxygen atom is bonded to two carbon atoms.
–C–O–C– .
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59. Aldehydes and Ketones
An aldehyde contains a carbonyl group (C=O), which is a carbon atom with a double bond to an oxygen atom.
In a ketone, the carbon of the carbonyl group is attached to two other carbon atoms.
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60. 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.
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61. 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.
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62. Functional Groups Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings

63. Learning Check 1) CH3─CH2─CH2─OH 2) CH3─O─CH2─CH3 3) CH3─CH2─NH2 O O
Classify each of the following as: alcohol, ether, aldehyde, ketone, carboxylic acid, ester, amine or amide.
1) CH3─CH2─CH2─OH
2) CH3─O─CH2─CH3
3) CH3─CH2─NH2
O O
║ ║
4) CH3─C─OH 5) CH3─C─O─CH3

64. Solution 1) CH3─CH2─CH2─OH alcohol 2) CH3─O─CH2─CH3 ether
3) CH3─CH2─NH2 amine
O O
║ ║
4) CH3─C─OH 5) CH3─C─O─CH3
carboxylic acid ester