Alcohols (Encyclopedia of Science)
Alcohols are organic (carbon-containing) compounds derived from hydrocarbons (organic compounds composed of only carbon and hydrogen). They are formed by replacing the hydrogen atoms in their parent hydrocarbons with one or more hydroxyl groups. Each hydroxyl group (H) is made up of one atom of oxygen and one atom of hydrogen and is referred to as a functional group. Functional groups generally determine how a molecule will behave. Alcohols with one hydroxyl group include methanol, ethanol, and propanol.
Names and properties
Alcohols are named from their parent hydrocarbon by substituting the suffix -ol for the final -e. For example, ethane becomes ethanol, methane becomes methanol, and propane becomes propanol.
The lower an alcohol's molecular weight (determined by the number of carbon atoms), the more soluble it is (or the easier it can be dissolved) in water. A greater number of hydroxyl groups (H) also increases water solubility because hydrogen bonds can form between the alcohol molecule and water. As the number of carbon atoms increases, hydrogen bonding is disturbed and solubility in water decreases. Hydrogen bonding is also a factor in the boiling points of alcohols. In this case, hydrogen bonds can form between hydrogen and oxygen atoms in adjacent molecules (molecules located next to each other). When alcohols are heated, the energy...
(The entire section is 1119 words.)
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