Carboxylic acids are just one member of a class of acyl derivatives, RCOY, where the acyl group is bonded to an electronegatives substituent -Y that can act as a leaving group in substitution reactions. Numerous acyl derivatives are possible, but we’ll be concerned only with four of the more common ones, in addition to carboxylic acids themselves: acid halides, acid anhydrides, esters, and amides

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

1.12A The Structure of Methane sp3 Hybridization The 4 sp3 orbitals should be oriented at angles of 109.5° with respect to each other. An sp3-Hybridized carbon gives a tetrahedral structure for methane, and with four equivalent C—H bonds

More environment-friendly methods Natural insect attractants — instead pesticide Less reactive compounds organic refrigerants and aerosol propellant — instead Freon (that destroy the Earth’s ozone layer) Cars with more efficient combustion engines — reduce the massive amount of automobile

把数学测验目标逐级分解为指标系统,使各个指标都可以直接进行 测量的量化要素就是编制数学测验。编制数学测验一般有以下主要步骤

Primary alcohols can be oxidized to aldehydes and carboxylic acids

Conjugated unsaturated systems have a p orbital on a carbon adjacent to a double bond The p orbital can come from another double or triple bond The p orbital may be the empty p orbital of a carbocation or a p orbital with a single electron in it (a radical)

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

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

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