1858 ~ 1861, Kekulé, Couper, and Butlerov, laid the basis for one of the most fundamental theories in chemistry: the structural theory. Valence（化合价）: C — tetravalent; O — divalent; H — monovalent

A hydrocarbon whose molecules contain two double bonds is called an alkadiene(alkatriene for three double bonds); A hydrocarbon with two triple bonds is called an alkadiyne; A hydrocarbon with a double and triple bond is called an alkenyne

A UV-Vis spectrophotometer measures the amount of light absorbed at each wavelength of the UV and visible regions of the electromagnetic spectrum. λmax— the wavelength of maximum absorption

A ring that contains at least one heteroatom (an atom other than carbon) is called a heterocycle, and a substance based on a heterocyclic ring is a heterocyclic compound. Heterocyclic compounds containing N, O or S are by far the most common

The most characteristic reactions of benzenoid arenes are the substitution reactions that occur when they react with electrophilic reagents. The electrophiles are either a positive ion (E+) or some other electron-deficient species with a large partial positive charge

Aldehydes are named by replacing the terminal –e of the corresponding alkane name with –al. The longest chain selected as the base name must contain the –CHO group, and the –CHO carbon is always numbered as carbon 1

Quinones are an interesting and valuable class of compounds because of their oxidation-reduction, or redox, properties. The redox properties of quinones are important to the functioning of living cells, where compounds called ubiquinones(泛醌) act as biochemical oxidizing agents to mediate the electro-transfer processes involved in energy production

Functional groups The structural features that make it possible to classify compounds by reactivity are called functional groups. A functional group is a part of a larger molecule and is composed of an atom or a group of atoms that have a characteristic chemical behavior. The Chemistry of every organic molecules

An acid is a substance that can donate (or lose) a proton, A base is a substance that can accept (or remove) a proton

The primary source of alkanes is petroleum Natural gas consists chiefly of methane, but ethane, propane, butane, and isobutane are also present. Petroleum is a complex mixture of hydrocarbons that must be refined into different fraction before it can be used