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Methane - Ethane - Propane – Butane...


Methane - Ethane - Propane – Butane...


In organic chemistry, an alkane is a saturated hydrocarbon consisting of a noncyclic open chain in which the molecule has a maximum of hydrogen atoms and therefore its single bonds.


Alkanes are also known as paraffins, or collectively as "paraffin chain" and these terms can also be used for alkenes, which contain a single unbranched chain of carbon atoms, and when there are branches in the alkanes chain, it is called "isoparaffins" and alkanes belong to aliphatic compounds.



Common simple alkanes

1.      Methane

2.     Ethane

3.     Propane

4.    Butane

5.     Pentane

6.     Hexane

7.     Heptane

8.     Octane

9.     Nonane

10.  Decane








Molar mass






16.04 g/mol






30.07 g/mol






44.09 g/mol






58.12 g/mol






72.15 g/mol






86.17 g/mol






100.2 g/mol






114.2 g/mol






128.2 g/mol






142.2 g/mol



Alkanes Formula

1. Methane Formula


1. Methane Formula



2. Ethane Formula


2. Ethane Formula


3. Propane Formula


3. Propane Formula


4. Butane Formula


4. Butane Formula


5. Pentane Formula


5. Pentane Formula


6. Hexane Formula


6. Hexane Formula


7. Heptane Formula


7. Heptane Formula


8. Octane Formula


8. Octane Formula


9. Nonane Formula


9. Nonane Formula


10. Decane Formula


10. Decane Formula



Aliphatic hydrocarbons

Aliphatic hydrocarbons are hydrocarbons in which the carbon and hydrogen atoms are connected by straight or branched chains or bonds, but not aromatic, and are divided into saturated aliphatic compounds where all single carbon bonds are attached to hydrogen atoms such as alkanes and unsaturated such as alkenes. and alkynes.[1]


Hydrocarbons are divided into aromatic (aromatic) hydrocarbons and aliphatic hydrocarbons, examples of aliphatic hydrocarbons are ethane (C2H6), ethene (C2H4) and ethane (C2H2), with methane (CH4) being the simplest. Hydrogen is like oxygen, nitrogen, chlorine, and sulfur.[2]



Categories of aliphatic hydrocarbons

Aliphatic hydrocarbons are divided into two main categories, as follows: [3]


Saturated aliphatic hydrocarbons

This is the simplest section of aliphatic hydrocarbons and includes the alkanes family, and it is characterized by the following: [3]

1.      All bonds between carbon atoms are single bonds.

2.     It can be represented as (CnH2n+2), where (n, an integer).

3.     Carbon forms a tetrahedral partial structure by bonding with hydrogen atoms.

4.     The bond between C-C and H-C is of the sigma type.

5.     The simplest alkanes are methane (CH4), ethane (C2H6), and propane (C3H8).

6.     Alkanes with carbon atoms of 4 and more have isomers where the isomers beginning with the word (n) line up with adjacent carbons, while the one that begins with the word (iso) in which one of the carbons is branched from the chain such as butane (n-butane) and the Ayyubids (in English: Isobutane).

7.      Isomers differ in their physical and chemical properties, despite having the same number of atoms, but they are different compounds.

8.     There is no upper limit to the number of carbon atoms in alkanes, there are industrial alkanes chains in which the number of carbon atoms reaches more than 300 atoms, as used in the manufacture of polymers, and this means that the number of isomers will also be very large for some compounds, reaching millions of isomers! \

9.     If one carbon atom is bonded to another carbon in the compound, the compound will become a cycloalkane.

10.  The simplest cyclopropane is cyclopropane where (CnHn), (n, an integer greater than 2) represents the general equation for cycloalkanes.

11.    The general naming system for alkanes depends on the number of carbon atoms in them. The regular name (IUPAC) is different. The name is based on the number of chain carbons preceded by a syllable indicating the number of branched carbons. Example: 3-methylheptane is the regular name, for iso-octane, in which the branching is located on The third carbon atom.



Unsaturated aliphatic hydrocarbons

They are called unsaturated because carbon atoms are linked to a smaller number of hydrogen atoms than is assumed, because they contain double or triple bonds among themselves. Unsaturated aliphatic hydrocarbons can be divided into two main types, as follows: [4]



Alkenes are characterized by the following: [4]

1.      They contain one or more double bonds between carbon atoms.

2.     The double bond consists of a sigma bond and a pi bond.

3.     Different geometries of compounds due to double bonds lead to diverse properties.

4.     Cyclic alkenes may be present.

5.     Ethene (C2H4) is the simplest alkene and is also called ethylene, followed in order by propene or propylene, butene and its isomers, and so on.

6.     The naming system is based on the replacement of ane in alkane to ene in alkene.

7.      Isomers are named based on the position of the carbon double bond and mention the number of the smallest atom attached to the double bond, eg 1-butene means that the first carbon atom has the double bond.

8.     The systematic naming system is based on the identification of the longest chain containing the double bond and the name of the alkene is given by the number of the smallest carbon of the double bond preceded by the numbers of the carbon atoms containing the branch block.




Alkynes are characterized by the following: [4]

1.      The presence of at least one triple bond between carbon atoms.

2.     A triple bond consists of one sigma bond and two pi bonds.

3.     The linear shape (180° angle) between the two carbon atoms bonded by the triple bond.

4.     Toroidal objects can exist.

5.     The simplest compound of this group is ethene (C2H2) known as acetylene.

6.     Alkynes are named by replacing the ene syllable in alkenes with the yne syllable in alkynes.

7.      The systematic naming system depends on identifying the longest chain containing the triple bond, and the name of the alkene is given by the number of the smallest carbon atom of the triple bond preceded by the numbers of the carbon atoms containing the section representing the branching, an example of an alkyne of five carbon atoms of the triple bond at the third atom and branching on the first atom: (1- methyl 3-pentane).





1.      Anne Marie Helmenstine (3/7/2019), "Aliphatic Hydrocarbon Definition", Thought co, Retrieved 1/2/2022. Edited.

2.     BYJUS (1/2/2022), "Aliphatic Hydrocarbons", BYJUS, Retrieved 1/2/2022. Edited.

3.     Francis A. Carey (20/7/1998), "Hydrocarbon", Britannica, Retrieved 2/2/2022. Edited.

4.     Chemistry libertexts (24/9/2021), "Aliphatic Hydrocarbons", Chemistry libertexts, Retrieved 2/2/2022. Edited.