Question

Predict whether each of the following compounds is saturated or unsaturated as indicated by the name. (a) eicosane (b) dodecene

Short answer

Eicosane is saturated; dodecene is unsaturated.

Step-by-step solution

Understand the Terms 'Saturated' and 'Unsaturated'

In organic chemistry, 'saturated' compounds contain only single bonds between carbon atoms, while 'unsaturated' compounds have at least one multiple bond (double or triple) within their carbon chains.

Analyze the Compound Name Eicosane

The term 'eicosane' indicates an alkane, which is a type of saturated hydrocarbon comprised entirely of single bonds between carbon atoms. This is evident from the suffix '-ane,' which denotes alkanes with only single bonds.

Analyze the Compound Name Dodecene

The term 'dodecene' suggests an alkene, which is a type of unsaturated hydrocarbon, as indicated by the suffix '-ene.' This suffix denotes the presence of at least one double bond between carbon atoms, making it unsaturated.

Key concepts

Saturated Compounds

Saturated compounds are a foundational concept in organic chemistry. They are molecules that consist entirely of carbon atoms connected by single bonds. This means that each carbon atom within the molecule forms four single covalent bonds—either with hydrogen atoms or other carbon atoms. Therefore, saturated compounds are also referred to as "saturated hydrocarbons."
One of the most common examples of saturated compounds are alkanes. These straight or branched chains adhere to the formula \(C_nH_{2n+2}\). The singular bond structure in saturated compounds makes them significantly stable and less chemically reactive compared to their unsaturated counterparts. This stability results from the lack of multiple bonds, which typically introduces strain or reactivity within a molecule's structure. Saturated compounds like alkanes are prevalent in waxes, fats, and oils, making them crucial in numerous everyday applications.

Unsaturated Compounds

Unsaturated compounds contain one or more multiple bonds, such as double or triple bonds, between carbon atoms. These multiple bonds allow unsaturated compounds to participate in a variety of chemical reactions that saturated compounds typically cannot, such as addition reactions. This makes unsaturated compounds more reactive due to the presence of these reactive sites.
Unsaturated compounds are divided into two main groups: alkenes and alkynes. Alkenes feature at least one double bond in their structure and follow a general formula of \(C_nH_{2n}\). On the other hand, alkynes contain at least one triple bond and adhere to a general formula of \(C_nH_{2n-2}\). The presence of these multiple bonds not only enhances the reactivity of unsaturated compounds but also significantly influences their geometry. For example, a double bond introduces rigidity and restricts rotation, impacting the molecule's shape and potential interactions.

Alkanes and Alkenes

Alkanes and alkenes are prominent representatives of the hydrocarbon family in organic chemistry. Both share a commonality in being composed of only carbon and hydrogen, but differ critically in their bonding.

• Alkanes: Known for featuring only single bonds, alkanes are saturated hydrocarbons. They are typically named with the suffix '-ane' and are exemplified by compounds like "eicosane". Alkanes tend to be less reactive due to this saturation, making them suitable for applications requiring stability such as fuels and lubricants.
  
• Alkenes: These are unsaturated hydrocarbons containing at least one carbon-carbon double bond, indicated by the '-ene' suffix, as seen in names like "dodecene". The presence of a double bond introduces unique reactivity characteristics, allowing alkenes to undergo addition reactions, forming the basis for polymers and other complex molecules.

Both alkanes and alkenes are essential for various chemical industries, including the production of plastics, pharmaceuticals, and petrochemicals. Understanding their structural and chemical differences is crucial for students studying organic chemistry.