Carbon dioxide (CO2) - a gas with a subtle sour taste, does not have no color, no odor.Its concentration in the atmosphere is on average about 0.04%.On the one hand, to maintain life it is absolutely unsuitable.And on the other - without carbon dioxide all the vegetation simply would have died, since he is the "power source" for the plants.In addition to the Earth's CO2 is a certain kind of blanket.If there was an atmosphere of this gas, our planet would be much colder and the rains have stopped almost completely.
«Blanket Earth»
form carbon dioxide (carbon dioxide, CO2) is a result of combining two of its components: oxygen and carbon.This gas is formed everywhere, where there is combustion of coal or hydrocarbon compounds.It is also released during the fermentation of liquids and the product of respiration in animals and humans.To date, the properties of carbon dioxide are well studied.It is known that the gas is heavier than air and colorless.When combined with water, it forms carbonic acid, which is widely used in various carbonated drinks.
why scientists often say that CO2 - a quilt of our planet?The fact that the carbon dioxide passes freely coming to us from space ultraviolet rays and reflects infrared radiation emitted from the earth.Therefore, the sudden disappearance of this gas from the atmosphere in the first place would have affected the climate.However, the probability of such a disaster is practically zero, because the burning of wood, natural gas, coal and oil gradually increases the concentration of carbon dioxide in the atmosphere.And now the fear is not so much cooling as the mass of melting glaciers on the poles, and increasing the level of the oceans ...
Dry ice
In the liquid state the gas is stored in cylinders with high pressure (70 bar).If you open the valve of the steel vessel, will begin to break out of the hole ... snow.What kind of miracles?The explanation of this fact is quite simple.When compressing carbon dioxide expended work which, by its size significantly less than that required for its expansion.To compensate for the shortage of CO2 arising quenched and transformed into a "dry ice".Compared with a conventional ice it has a number of important advantages: first, evaporation takes place completely without formation of residues.And secondly, the "cooling power" dry ice per unit weight twice.
Application
Carbon dioxide is often used as an inert atmosphere in the welding wire.However, at higher temperatures, decomposition occurs with liberation of its oxidizing metal oxygen.Therefore, the welding wire was added scavengers, such as silicon and manganese.Carbon dioxide in cans commonly used in pneumatic guns and in aircraft construction.Liquid gas is used as a fire extinguisher, and for making lemonade and soda.In addition, carbon dioxide CO2 is also used as a food additive (Code E290).And as we all know means to loosen the dough.Besides, the solid carbon dioxide is widely used for preserving food products.
