According to the type of covalent bonds breaking,organic reactions can be classified three kinds: radical reactions(自由基反应)，ionic reactions and concerted reactions(协同反应).Bond breaking during radical reaction involves homolytic cleavage where the bonding electrons move to different atoms, to generate a free radical intermediate; bond breaking during ionic reaction involves heterolytic cleavage where the bonding electrons move as a pair onto one atom,to generate a positive and negative ionic intermediate;during the concerted reactions, the bonds breaking and forming carry out at the same time,none intermediate generate.
Before studing an organic compound, it needs to separate and purify the organic compounds at first. Then it needs to examine the element types, numbers and molecular weight of the compound to determined by UV(Ultraviolet),IR（Infra-red）,MS( Mass Spectrometry) and NMR(Nuclear Magnetic Resonance).
Understanding of organic chemistry lead to a better understanding of life chemistry and how the body works at the molecular level. It also helps in the understanding of the molecular mechanisms invovlved in disease and bodily malfunction,leading in turn to an unerstanding of how drugs can be designed to curethese disease states.