The identification and characterization of the structures of unknown substances characterizing unknown organic compounds in terms of their functional group .Chemists are often able to use both the physical and chemical properties of an unknown compound to help identify it. Physical Physical properties are those .The Identification of Organic Compounds. A Manual of Qualitative and Quan.ative Methods. R. A. Swenson. J. Am. Chem. Soc. , 1962, 84 9 , pp 1768-1769..Compound Identification: A Journal of Agricultural and Food Chemistry Perspective The systematic identification of organic compounds: A laboratory manual..