The Difference Between Alkanes, Alkenes, and Alkynes

Chemistry, Education
[caption id="attachment_16044" align="alignright" width="440"] An acetylene (ethyne) torch.[/caption] Alkanes, alkenes, and alkynes are made up of carbon and hydrogen. The carbon atoms in each exhibit a valency of four.  Though these three hydrocarbon varieties are similar, there is a difference in bonding. We illustrate this with the simplest example: ethane vs. ethene vs. ethyne. Common and Scientific Names Common names are names given to many compounds, but they may mislead the uninitiated. For instance, the scientific names of alkenes contain the suffix –en(e) as part of their name. But acetylene is not an alkene. It is an alkyne. The scientific names of alkynes contains the suffix –yne. Acetylene is scientifically named ethyne. Yet, it nomenclature is not the only difference between alkanes, alkenes, and alkynes. Alkanes Alkanes are completely saturated…
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Ethane Sigma Bond Rotation Conformers

[caption id="attachment_14316" align="alignright" width="440"] Methane Ball & Stick Model[/caption] Methane is the smallest molecule consisting of just carbon and hydrogen, CH₄. The second smallest hydrocarbon is ethane, C₂H₆. It is sometimes written H₃C–CH₃. The “dash” between the two carbon atoms represents a single bond. It is also a sigma bond. What is a sigma bond? And what are ethane sigma bond rotation conformers? What is a Sigma Bond? The carbon to carbon single bond is a covalent bond. That is, bonding electrons lying between the two carbon atoms are shared equally. A sigma bond is the strongest variety of covalent bond. The two atoms overlap head-on. One could view such a bond as being of cylindrical symmetry or like a straight line between the two atoms. Hence, the dash notation.…
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