1. Chapter 6 Ionic and Molecular Compounds
6.7 Names and Formulas of Alkanes
Learning Goal Write the IUPAC name and draw the condensed structural formula for an alkane.

2. Alkanes
Alkanes
are a class of hydrocarbons in which all atoms are connected by single bonds
are commonly used as fuels
contain carbons connected in a row or a continuous chain

3. Naming Alkanes
The IUPAC (International Union of Pure and Applied Chemistry) system is used for naming alkanes.
Alkanes with five or more carbons in a chain are named using prefixes and the ending ane.
Pentane is a five-carbon chain.
Octane is an eight-carbon chain.

4. Naming Alkanes

5. Condensed Structural Formulas
In a condensed structural formula, each carbon atom and its attached hydrogen atoms are written as a group. A subscript is used to represent the number of hydrogen atoms attached to each carbon.

6. Models for Larger Alkanes
Alkanes with more than three carbons are written in a zigzag pattern instead of a straight line. We can use different models to represent these molecules.

7. Learning Check
A. What is 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?

8. Solution
A. H H H H H      HCCCCCH H H H H H CH3CH2CH2CH2CH3 B. What is its molecular formula? C5H12 C. What is its name? pentane

9. Learning Check
Draw the condensed structural formula for heptane.

10. Solution
Draw the condensed structural formula for heptane. The prefix in heptane indicates that the condensed structural formula contains seven carbon atoms. Heptane CH3CH2CH2CH2CH2CH2CH3

11. Alkanes are nonpolar and less dense than water. Alkanes with
Properties of Alkanes
Alkanes are nonpolar and less dense than water. Alkanes with
1-4 carbon atoms are gases
5-8 carbon atoms are liquids
at room temperature
9-17 carbon atoms are liquids
such as kerosene and jet fuel
18 or more carbon atoms are
waxy solids
The solid alkanes that make up waxy coatings on fruits and vegetables help to retain moisture, inhibit mold, and enhance appearance.

12. Chemistry Link to Industry
Crude oil, or petroleum, contains a wide variety of hydrocarbons. At a refinery, the components in crude oil are separated by fractional distillation, a process that separates groups of hydrocarbons by continually heating the mixture to higher temperatures.

13. Chemistry Link to Industry
Alkanes with longer carbon chains require higher temperatures to reach their boiling point and form gases.

14. Concept Map, Ionic and Molecular Compounds