To recognize and also name simple (straight-chain) alkanes offered formulas and also compose formulas for straight-chain alkanes offered their names.

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We start our research of organic surfacetoairnewyork.comistry with the hydrocarbons, the most basic organic compounds, which are composed of carbon and hydrogen atoms just. As we detailed, tright here are several different kinds of hydrocarbons. They are distinguiburned by the types of bonding in between carbon atoms and the properties that outcome from that bonding. Hydrocarbons via just carbon-to-carbon single bonds (C–C) and also existing as a consistent chain of carbon atoms additionally bonded to hydrogen atoms are dubbed alkanes (or saturated hydrocarbons). Saturated, in this situation, implies that each carbon atom is bonded to four various other atoms (hydrogen or carbon)—the most possible; there are no double or triple bonds in the molecules.


The word saturated has the very same interpretation for hydrocarbons as it does for the dietary fats and also oils: the molecule has actually no carbon-to-carbon double bonds (C=C).


We formerly introduced the three simplest alkanes—methane (CH4), ethane (C2H6), and also propane (C3H8) and they are displayed aget in Figure (PageIndex1).

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api/deki/files/27399/12.2.jpg?revision=1" />Figure (PageIndex2): The Tetrahedral Methane Molecule

Methane (CH4), ethane (C2H6), and also propane (C3H8) are the start of a collection of compounds in which any two members in a sequence differ by one carbon atom and 2 hydrogen atoms—namely, a CH2 unit. The initially 10 members of this series are offered in Table (PageIndex1).

Table (PageIndex1): The First 10 Straight-Chain Alkanes Name Molecular Formula (CnH2n + 2) Condensed Structural Formula Number of Possible Isomers
methane CH4 CH4
ethane C2H6 CH3CH3
propane C3H8 CH3CH2CH3
butane C4H10 CH3CH2CH2CH3 2
pentane C5H12 CH3CH2CH2CH2CH3 3
hexane C6H14 CH3CH2CH2CH2CH2CH3 5
heptane C7H16 CH3CH2CH2CH2CH2CH2CH3 9
octane C8H18 CH3CH2CH2CH2CH2CH2CH2CH3 18
nonane C9H20 CH3CH2CH2CH2CH2CH2CH2CH2CH3 35
decane C10H22 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3 75

Consider the series in Figure (PageIndex3). The sequence starts through C3H8, and also a CH2 unit is included in each step relocating up the series. Any family of compounds in which nearby members differ from each various other by a definite aspect (here a CH2 group) is called a homologous series. The members of such a collection, dubbed homologs, have actually properties that vary in a continuous and predictable manner. The principle of homology offers company to organic surfacetoairnewyork.comisattempt in a lot the exact same means that the regular table offers company to inorganic surfacetoairnewyork.comisattempt. Instead of a bewildering range of individual carbon compounds, we can examine a couple of members of a homologous series and from them deduce some of the properties of various other compounds in the series.

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Figure (PageIndex3): Members of a Homologous Series. Each succeeding formula incorpoprices one carbon atom and also two hydrogen atoms more than the previous formula.