25.1. Hydrocarbons http://www.ck12.org
- Hydrocarbons can be classified as aliphatic or aromatic, depending on the absence or presence of an aromatic
ring. - Alkanes are saturated hydrocarbons. The carbon atoms in an alkane may be arranged in a straight chain, or
they may be branched. Alkanes can be named by following a systematic method developed by the IUPAC. - Alkenes and alkynes are unsaturated hydrocarbons that contain a double or triple covalent bond.
- Isomers are molecules that consist of the same atoms in different arrangements. Isomers may be structural,
geometric, or optical.
Lesson Review Questions
Reviewing Concepts
- How many covalent bonds do carbon atoms form in compounds, and why?
- What do the terms saturated and unsaturated mean when applied to hydrocarbons?
- Give the general formulas for alkanes, alkenes, and alkynes.
- Why do alkenes display geometric isomerism, but alkanes do not?
- What condition must be met for a given molecule to have an optical isomer?
Problems
- An alkane has 13 carbon atoms. What is its molecular formula?
- Name the following hydrocarbons.
a. CH 3 (CH 2 ) 3 CH 3
b. CH 3 CH 2 CH 2 CH=CHCH 2 CH 3
c. CH≡CCH 3 - Name the following branched alkanes.
a.b.- Draw structural formulas for the following compounds.
a.cis-2-pentene
b. 1-hexyne
c. 2,2,3,6-tetramethyloctane
d. 2,4-heptadiene