http://www.ck12.org Chapter 9. Chemistry of Carbon
Lesson Summary
- Hydrocarbons are compounds that contain only carbon and hydrogen. They are the simplest type of carbon-
based compounds. - Saturated hydrocarbons contain only single bonds between carbon atoms. They are also called alkanes. They
may form straight-chain, branched-chain, or cyclic molecules. Compounds with the same number of atoms
but different shapes are called isomers. - Unsaturated hydrocarbons contain at least one double or triple bond between carbon atoms. Hydrocarbons
with double bonds are called alkenes. Those with triple bonds are called alkynes. Aromatic hydrocarbons
consist of six carbon atoms in a ring shape, connected by alternating single and double bonds. - Hydrocarbons are extremely important to modern life. Their most important use is as fuels. Hydrocarbons are
also used to manufacture many products including plastics. The main source of hydrocarbons is fossil fuels.
Lesson Review Questions
Recall
- What are hydrocarbons?
- Describe how the boiling point of alkanes changes as the number of carbon atoms per molecule increases.
- Identify and describe the three basic shapes of alkane molecules.
- What are isomers?
- Define alkene and alkyne.
- Describe aromatic hydrocarbons.
Apply Concepts
- Which type of hydrocarbon is represented by this structural formula? What is the compound’s chemical
formula? What shape does it have?
Think Critically
- Compare and contrast saturated and unsaturated hydrocarbons. Give an example of each.
- Explain the relationship between plastics and fossil fuels.
Points to Consider
In this lesson, you read that fossil fuels form from the remains of dead organisms. As you will read in the next
lesson, "Carbon and Living Things," organisms are made of carbon-based compounds.