Sugar is a general name for group of sweet soluble carbohydrates, many of which are used in foodstuff. These carbohydrates consist of carbon, hydrogen and oxygen.
There are different types of sugar. The simplest type is monosaccharides which part glucose, fructose and a galactose are. The table or granulated sugar which is usually used in food is a disaccharide sucrose. Other disaccharides are a maltose and lactose. Types of sugar with participation of long chains of molecules are called oligosaccharides.
The majority of connections of this kind are expressed through a formula CnH2nOn. (n - this number which can vary from 3 to 7). The formula of glucose is C6H12O6.
Some monosaccharides can form communications with other monosaccharides, forming disaccharides (sucrose) and polysaccharides (starch). At consumption of sugar in food enzymes split these communications, and sugar is digested. After digestion and absorption by blood and fabrics monosaccharides turn into glucose, fructose and a galactose. Monosaccharides pentose and hexose form ring structure.
Main monosaccharides
Glucose, fructose and galactose belong to the main monosaccharides. They have five hydroxyl groups (-OH) and one carbonyl group (C=0). Glucose, a dextrose or glucose meets in fruit and vegetable juice. It is primary product of photosynthesis. Glucose can be received from starch by addition of enzymes or in the presence of acids. Fructose or fruit sugar is present at fruit, some root crops, cane sugar and honey. It is the most sweet sugar. Fructose is a part of table sugar or sucrose. The galactose does not meet in pure form. But it is a part of glucose of disaccharide of lactose or milk sugar. It is less sweet, than glucose. The galactose is a part of the antigens which are on the surface of blood vessels.
Disaccharides
Sucrose, maltose and lactose belong to disaccharides. A chemical formula of disaccharides - C12H22O11. They are formed thanks to connection of two molecules of monosaccharides except for one molecule of water. Sucrose meets in the nature in stalks of cane sugar and root crops of sugar beet, some plants, carrots. The molecule of sucrose represents connection of molecules of fructose and glucose. Its molar weight is equal to 342.3. The maltose is formed during shoots of seeds of some plants, such as barley. The molecule of a maltose is formed thanks to connection of two molecules of glucose. This sugar less sweet, than glucose, sucrose and fructose. Lactose meets in milk. Its molecule represents connection of molecules of a galactose and glucose.
How to find the molar mass of a molecule of sugar
To count the molar mass of a molecule, it is necessary to put atomic masses of all atoms in a molecule. Molar mass of C12H22O11 = 12 (weight C) + 22 (weight H) + 11 (weight O) = 12 (12.01) + 22 (1.008) + 11 (16) = 342.30