Name the First 10 Alkanes

List the Simplest Hydrocarbons

Stylized illustration of a Methane molecule
Methane is the simplest alkane. INDIGO MOLECULAR IMAGES / Getty Images

Alkanes are the simplest hydrocarbon chains. These are organic molecules that consist only of hydrogen and carbon atoms in a tree-shaped structure (acyclic or not a ring). These are commonly known as paraffins and waxes. Here is a list of the first 10 alkanes.

methane CH4
ethane C2H6
propane C3H8
butane C4H10
pentane C5H12
hexane C6H14
heptane C7H16
octane C8H18
nonane C9H20
decane C10H22
Table of the First 10 Alkanes

How Alkane Names Work

Each alkane name is built from a prefix (first part) and a suffix (ending). The -ane suffix identifies the molecule as an alkane, while the prefix identifies carbon skeleton. The carbon skeleton is how many carbons are linked to each other. Each carbon atom participates in 4 chemical bonds. Every hydrogen is joined to a carbon.

The first four names come from the names methanol, ether, propionic acid, and butyric acid. Alkanes that have 5 or more carbons are named using prefixes that indicate ​the number of carbons. So, pent- means 5, hex- means 6, hept- means 7, and so on.

Branched Alkanes

The simple branched alkanes have prefixes on their names to distinguish them from the linear alkanes. For example, isopentane, neopentane, and n-pentane are names of branched forms of the alkane pentane. The naming rules are somewhat complicated:

  1. Find the longest chain of carbon atoms. Name this root chain using the alkane rules.
  2. Name each side chain according to its number of carbons, but change the suffix of its name from -ane to -yl.
  3. Number the root chain so that the side chains have the lowest possible numbers.
  4. Give the number and name of the side chains before naming the root chain.
  5. If multiples of the same side chain are present, prefixes such as di- (two) and tri- (for three) indicate how many of the chains are present. The location of each chain is given using a number.
  6. The names of multiple side chains (not counting di-, tri-, etc. prefixes) are given in alphabetical order before the name of the root chain.

Properties and Uses of Alkanes

Alkanes that have more than three carbon atoms form structural isomers. Lower molecular weight alkanes tend to be gases and liquids, while larger alkanes are solid at room temperature. Alkanes tend to make good fuels. They are not very reactive molecules and do not have biological activity. They do not conduct electricity and not appreciably polarized in electric fields. Alkanes don't form hydrogen bonds, so they aren't soluble in water or other polar solvents. When added to water, they tend to decrease the entropy of the mixture or increase its level or order. Natural sources of alkanes include natural gas and petroleum.

Sources

  • Arora, A. (2006). Hydrocarbons (Alkanes, Alkenes And Alkynes). Discovery Publishing House Pvt. Limited. ISBN 9788183561426.
  • IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). "Alkanes". doi:10.1351/goldbook.A00222
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Helmenstine, Anne Marie, Ph.D. "Name the First 10 Alkanes." ThoughtCo, Aug. 27, 2020, thoughtco.com/the-first-10-alkanes-608696. Helmenstine, Anne Marie, Ph.D. (2020, August 27). Name the First 10 Alkanes. Retrieved from https://www.thoughtco.com/the-first-10-alkanes-608696 Helmenstine, Anne Marie, Ph.D. "Name the First 10 Alkanes." ThoughtCo. https://www.thoughtco.com/the-first-10-alkanes-608696 (accessed April 20, 2024).