1. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.1 Chapter 11 Introduction to Organic Chemistry: Alkanes 11.2 Alkanes

2. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.2 Names of Alkanes The names of alkanes  are determined by the IUPAC (International Union of Pure and Applied Chemistry) system  use a prefix to indicate the number of carbons in a chain  end in -ane

3. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.3 IUPAC Names for Alkanes

4. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.4 Learning Check A. Give the name of each compound: 1) CH 3 —CH 3 2) CH 3 —CH 2 —CH 3 3) CH 3 —CH 2 —CH 2 —CH 2 —CH 2 —CH 3 B. Write the condensed structural formula of pentane.

5. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.5 Solution A. Give the name of each compound: 1) CH 3 —CH 3 ethane 2) CH 3 —CH 2 —CH 3 propane 3) CH 3 —CH 2 —CH 2 —CH 2 —CH 2 —CH 3 hexane B. Write the condensed structural formula of pentane. CH 3 —CH 2 —CH 2 —CH 2 —CH 3

6. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.6 Structural Formulas Alkanes are written with structural formulas that are  expanded to show each bond  condensed to show each carbon atom and the attached hydrogen atoms

7. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.7 Line-Bond Formulas  Because each C atom has a tetrahedral arrangement, the order of atoms is not a straight line, but a zigzag pattern.  A line-bond formula abbreviates the carbon atoms and shows only the zigzag pattern of bonds from carbon atom to carbon atom.

8. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Types of Structural Formulas 8

9. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.9 Rotation Around a C  C Single Bond The groups attached to a C—C single bond  rotate around the bond  give different relative structural arrangements called conformations

10. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.10 Writing Structural Formulas Carbon atoms in a chain  maintain their tetrahedral shape  are connected in a zigzag pattern  are drawn as two-dimensional  can be written in several conformations

11. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.11 Structural Arrangements of Butane  Rotation of the end CH 3 -groups provides different structural arrangements for butane.

12. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.12 Hexane has Six Carbon Atoms Hexane  is an alkane with 6 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

13. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.13 Learning Check A. Draw the condensed structural formula of B. What is its molecular formula? C. What is its name?

14. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.14 Solution A. Draw the condensed structural formula: CH 3 ─CH 2 ─CH 2 ─CH 2 ─CH 3 B. What is its molecular formula? C 5 H 12 C. What is its name? pentane

15. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.15 Learning Check Draw the condensed structural formula for: A. Ethane B. Heptane

16. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.16 Solution Draw the condensed structural formula for: A. Ethane CH 3 ─CH 3 B. Heptane CH 3 ─CH 2 ─CH 2 ─CH 2 ─CH 2 ─CH 2 ─CH 3

17. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.17 Cycloalkanes  are cyclic alkanes  have 2H fewer than the alkane  are named by using the prefix cyclo- before the name of the alkane chain with the same number of carbon atoms

18. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.18 Cycloalkanes (continued) The structural formulas of cycloalkanes  are often shown as geometric figures

19. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.19 Cycloalkanes (continued)

20. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.20 Learning Check Name the following: A. CH 3 ─CH 2 ─CH 2 ─CH 3 B. C. CH 3 ─CH 2 ─CH 2 ─CH 2 ─CH 2 ─CH 2 ─CH 2 ─CH 3 D.

21. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.21 Solution Name the following: A. CH 3 ─CH 2 ─CH 2 ─CH 3 butane B. cyclopropane C. CH 3 ─CH 2 ─CH 2 ─CH 2 ─CH 2 ─CH 2 ─CH 2 ─CH 3 octane D. cyclohexane