Among all the substances on earth, due to its physical and chemical properties, water is exclusively the most important position in nature and plays an especially important role in human life. Water occupies 70% of the entire Earth’s surface and makes up approximately 70% of the human mass: the embryo is 95% water, in an adult it is 60% and in the body of a newborn child 75%. In old age, the number decreases.
Water is a whole unique chemical substance, by its property and structure. Water has no taste, color, smell, and its molecular weight is 18,0160. Distilled water has a maximum density of 1 g / cm3, with a relative pressure of 1 atm and a temperature of 3.9820С. It is a unique solvent. It is capable of dissolving more amounts of other substances and salts than any other liquid. Water can oxidize almost all solid metals and destroys rocks. This can be explained by the fact that water has a dielectric constant of 81.0 at a temperature of 200 ° C, while many other bodies are in the range of 2–3, with the exception of a number of acids (acetone 21 and formic 58) hydrogen cyanide – 107.
Water in the form of spherical droplets has a small surface with a given volume. The tension on the surface is approximately 72.75 dyn / cm, and this is a necessary condition for capillary processes.
The specific heat of water is the highest, and lower than that of most other substances (ammonia and other than hydrogen), at a temperature of 1000 C it is 0.487 cal / g-hail, and at 150 C it is 1,000 cal / g-hail. Water absorbs a large amount of heat, and at the same time heat up relatively little. With this absorption of additional heat, the temperature remains constant during boiling and the freezing temperature of water decreases, and with an increased pressure of about 10 ° C (for every 130 atm). When boiling, the pressure temperature of 1 atm is approximately 1000 ° C, and its component boils at negative temperature: hydrogen at -2530 ° C, oxygen at – 1800 ° C.