Chemistry is a unique and interesting science, withwhose help can explain many of the processes taking place around us in life. For example, why does iron gradually rust, and also why the aluminum spoon so quickly heats up if it is lowered into hot tea. Chemistry surrounds us absolutely everywhere: acetic acid or vinegar, sodium chloride or all known common salt, as well as substances such as iodine, chlorine, alcohol and many others. But there is a substance in chemistry that everyone knows, and it's called starch. Starch can also be obtained by chemical means, but most often it is extracted from potatoes. Let's take a closer look at all that is associated with it, starting with a chemical formula and ending with its properties and the way that starch can be recognized.
Starch, the formula of which looks as followsway: C6H10O5, has a number of interesting properties. For example, everyone loves kissel freezes only for the reason that it contains a fairly large amount of starch. It looks like starch as a regular powder, has no smell, is almost devoid of taste, and the most interesting is that it creaks if it is slightly rubbed. This physical property of starch is due to the fact that the molecules of starch are quite large.
In general, starch, its formula and some propertieswere discovered relatively recently. Starch is produced by plants, not only potatoes, but also others, such as, for example, corn and wheat. In potato, starch contains only twenty percent, and in wheat and corn kernels, its quantity exceeds the seventy percent mark. Starch is formed when photosynthesis combines six molecules of carbon dioxide and five water molecules, after which one molecule of starch and six molecules of oxygen are formed.
As indicated above, the chemical formulastarch contains six carbon atoms, ten hydrogen atoms and five oxygen atoms. This says not only that the molecule of starch is very large, but also that it has an absolutely organic origin, that is, it is part of a section of chemistry called organic. This substance is considered complex, refers to the section of polysaccharides, although it is not a sugar or a similar substance. Also, starch is referred to organic substances containing oxygen, or otherwise - oxygen-containing organic substances.
Structural formula of starch is also consideredcomplex, its structure can be viewed on the Internet, since it is simply impossible to transmit it on a letter. One can only say that starch, its formula more precisely, contains several OH-groups, each of which is connected to a carbon atom. Many people confuse this molecule with a molecule of some alcohol when they hear about the OH group, but in fact the starch is covered in the C6H10O5 molecule.
If you want to recognize starch, then you do notyou need a lot and a long time to think about it. A qualitative reaction to the presence of starch in the substance is as follows: a few drops of iodine solution are simply dripping into the tube. If the solution immediately becomes visible, you can undoubtedly sign the test tube and be sure that it contains starch. If you want to test this reaction in the wild, then take a small potato, cut it, then gently pipet drop a few drops of iodine (what is sold in pharmacies for moxibustion). After a while you will see the obvious effect of a qualitative reaction to starch: the potato in the place where iodine has got will gradually turn blue.
So, now you know about starch enougha lot (what is starch, formula, properties and a qualitative reaction). Of course, all the above information is not complete, but if you are preparing for credit for organic chemistry, it will certainly help you.
