Carbohydrates molecular formula

For the original carbohydrate molecular formula = C12H22O11 index of hydrogen deficiency = 2... 

Carbohydrates may be divided into monosaccharides, disaccharides and polysaccharides. The monosaccharides under certain conditions react as polyhydroxy-aldehydes or polyhydroxy-ketones two important representatives are glucose CjHjjO (an aldose) and fructose (laevulose) CgHuO, (a ketose). Upon hydrolysis di- and polysaccharides 3deld ultimately monosaccharides. Common disaccharides are sucrose, lactose and maltose (all of molecular formula C,2H2. 0,), whilst starch, dextrin and cellulose, (CjHjoOj), in which n > 4, are typical polysaccharides. 

Historically carbohydrates were once considered to be hydrates of carbon because their molecular formulas m many (but not all) cases correspond to C (H20) j It IS more realistic to define a carbohydrate as a polyhydroxy aldehyde or polyhydroxy ketone a point of view closer to structural reality and more suggestive of chemical reactivity... 

The word carbohydrate derives historically from the fact that glucose, the first simple carbohydrate to be obtained pure, has the molecular formula C6H,206 and was originally thought to be a "hydrate of carbon, C6(Tl20)6." This view was soon abandoned, but the name persisted. Today, the term carbohydrate is used to refer loosely to the broad class of polyhydroxvlated aldehydes and ketones commonly called sugars. Glucose, also known as dextrose in medical work, is the most familiar example. 

This is a very widely available polymer, since it is the main component of the cell walls of all plants. It is a carbohydrate of molecular formula (C5H q05), where n runs to thousands. The cellulose monomer is D-glucose, and the cellulose molecules are built up from this substance, effectively by condensation and removal of the elements of water. 

The carbohydrate family consists of a large number of naturally-occurring oxygen-rich organic compounds. The simplest carbohydrates - or "sugars" - have molecular formulas fitting the pattern (C.H 20)n, and appeared to early chemists to be "hydrated carbon." The more complex members of the family deviate from this pattern slightly. 

Problam 22.2 (a) Write a structural formula for (i) an aldotriose, (ii) a ketohexose, (iii) a deoxypentose. (b) Write molecular formulas for (i) a hexose trisaccharide, (ii) a pentose polysaccharide, (c) What is the general formula for most carbohydrates ... 

A term synonymous with carbohydrate is saccharide (sometimes sac-charvse). When referring to saccharides, the basic molecular formula is considered to be Compounds with this general formula, such as... 

The name carbohydrate dates back to a time when it was thought that all of these molecules were hydrates of carbon. For example the molecular formula for glucose is C6H1206, or six carbons plus six water molecules (H20). While these molecules make up the largest component of most foods, especially when calculated on a dry basis, their analysis was often avoided. For example, proximate analysis of food frequently involved analysis for moisture, fat, ash, and protein with the remaining portion considered carbohydrate of one form or another. 

The term carbohydrate arose because most sugars have molecular formulas Cffi(H20),n, suggesting that carbon atoms are combined in some way with water. In fact, the empirical formula of most simple sugars is C(H20). Chemists named these compounds hydrates of carbon or carbohydrates because of these molecular formulas. Our modern definition of carbohydrates includes polyhydroxyaldehydes, poly-hydroxyketones, and compounds that are easily hydrolyzed to them. 

Carbohydrates were given their name because their molecular formula could be written as Cn(H20)n, making them hydrates of carbon. 

Several examples of simple carbohydrates are shown. D-Glyceraldehyde and dihydroxyacetone have the same molecular formula, so they are constitutional isomers, as are D-glucose and D-fructose. 

Historically, carbohydrates were thought to be hydrates of carbon on the basis of their molecular formulas Cn(H20)m- More realistically, carbohydrates are now considered polyhydroxy aldehydes, polyhydroxy ketones, or substances that yield such compounds on acid hydrolysis. 

Saccharum is the Latin word for sugar and the derived term saccharide is the basis of a system of carbohydrate classification. The simplest sugars belong to the carbohydrate class, monosaccharide they include fructose and glucose. Glucose and fructose are structural isomers. The molecular formula is as follows ... 

C6H12O6, C4H6ON, and C15H31COOH considered as molecular formula for carbohydrate, protein, and fat, respectively. 

Originally, the English term carbohydrate was used for monosaccharides, the molecular formula of which corresponded to C (H20) . Because this formula can be regarded as the hydrate of a carbon atom, this class of compounds was called hydrate de carbone in French and Kohlenhydrate in German. 

The word carbohydrate derives historically from the fact that glucose, the first simple carbohydrate to be obtained pure, has the molecular formula C8Hi20g and was originally thought to be a hydrate of carbon, Ce(H20)g. ... 

FIGURE 1 Molecular formulas of some sweet molecules, representative of the major natural classes carbohydrates (sucrose), polyols (glycerol, sorbitol), amino acids (glycine, tryptophan), peptides (aspartame, monatin). 

Similarly, protein fibers like silk, which are polyamides and are degradable to mixtures of amino acids, cannot be directly synthesized from the latter. Another example is cellulose, which is a carbohydrate with molecular formula (C6Hio05)n, where n is a few thousand. The structure is... 

Early chemists noted that carbohydrates have molecular formulas that make them appear to be hydrates of carbon, C (H20) —whence the name. Eater structural studies revealed that these compounds were not hydrates because they did not contain intact water molecules, but the term carbohydrate persists. Carbohydrates are polyhydroxy aldehydes such as o-glucose, polyhydroxy ketones such as o-fmctose, and compounds such as sucrose that can be hydrolyzed to polyhydroxy aldehydes or... 

---