Final answer:
The presence of one or more double carbon-carbon bonds in a molecule, such as in alkenes, creates a different geometry, leading to changes in properties and behaviors of the molecule compared to saturated compounds without double bonds.
Step-by-step explanation:
The presence of one or more double carbon-carbon bonds in a molecule can cause significant changes in the molecule's physical and chemical properties. Organic compounds that contain one or more double bonds are described as unsaturated. These unsaturated hydrocarbons have less than the maximum number of hydrogen atoms that could potentially be attached to their carbon skeleton. A common type of unsaturated hydrocarbon molecule is called an alkene.
Alkenes, such as 1,3-butadiene, have a different geometry around the carbon atoms that participate in the double bonds. This altered geometry leads to distinctive molecular shapes and properties when compared to saturated hydrocarbons, which lack double bonds. Double bonds also introduce kinks in the carbon chain, affecting the molecule's hydrophobicity, as seen in some fatty acids where each cis double bond makes the chain act as though it were shorter.
Furthermore, double bonds can alternately occur in cyclic compounds, such as in some aromatic hydrocarbons where the carbons are arranged in a hexagon pattern. Additionally, the presence of multiple double bonds can lead to complex reactions like dimerization, which gives rise to more complex structures.