lo8 ORGANIC AGRICULTURAL CHEMISTRY 



subgroup is further divided into smaller groups depending 

 upon the number of carbon atoms in the molecule. The num- 

 ber of carbon atoms varies from two to nine and the names 

 indicate the number of carbon atoms. Monosaccharoses 

 which contain two carbons are called hi-oses and have the 

 formula C2H4O2; those containing three carbons are called 

 tri-oses with the formula CsHeOs. Similarly, the other sub- 

 groups of monosaccharoses are tetr-oses, C4H8O4, pent-oses, 

 C5H10O5, hex-oses, C6H12O6, hept-oses, C7H14O7, oct-oses, CsHieOs, 

 and non-oses, CgHisOg. Those of special importance and which 

 we shall study further are the trioses, pentoses and hexoses. 



The compound carbohydrates are known as poly-saccharoses, 

 which signifies that they are made up of more than one unit 

 sugar. This is proven by the fact that on hydrolysis they split 

 and yield two or more molecules of the monosaccharoses. They 

 are further divided into smaller groups according to the number 

 of monosaccharose molecules which they yield. Di-saccharoses 

 are those polysaccharoses which yield two molecules of mono- 

 saccharoses. Their formula is C„(H20)„_i, or C10H22O11, and 

 they are typified by the common sugar of commerce, cane 

 sugar. Tri-s ace har OSes are polysaccharoses which yield three 

 molecules of monosaccharoses. Their formula is C18H32O16 

 and an example is the sugar raffinose. Polysaccharoses, spe- 

 cifically so called in distinction from the two subgroups just 

 mentioned, are those polysaccharoses which yield an indefinite 

 number of molecules of monosaccharoses. This group is 

 typified by the common substances, starch and cellulose, with 

 the formula (CeHioOs)^.. A tabular presentation of the classi- 

 fication of carbohydrates will perhaps make the whole matter 

 clearer. 



