Carbon dioxide (CO 2 ) is a gas with a subtle sourish aftertaste that has no color or odor. Its concentration in the Earth’s atmosphere is on average about 0.04%. On the one hand, it is absolutely unsuitable for maintaining life. And on the other hand, without carbon dioxide, all vegetation would simply perish, since it is precisely it that serves as a “source of nutrition” for plants. In addition, for the Earth, CO 2 is a kind of blanket. If this gas were not in the atmosphere, our planet would become much cooler, and the rains would stop almost completely.
"Blanket of the Earth"
The formation of carbon dioxide (carbon dioxide, CO 2 ) occurs as a result of the combination of its two components: oxygen and carbon. This gas is formed wherever coal or hydrocarbon compounds burn. It is also released during the fermentation of liquids and as a respiratory product of animals and people. To date, the properties of carbon dioxide are fairly well understood. It is known that this gas is heavier than air and colorless. When combined with water, it forms carbonic acid, which is widely used in all kinds of carbonated drinks.
Why do scientists often say that CO 2 is the blanket of our planet? The fact is that carbon dioxide freely passes ultraviolet rays coming to us from space , and reflects infrared waves emitted by the Earth. Therefore, the sudden disappearance from the atmosphere of this gas would primarily affect the climate. However, the likelihood of such a catastrophe is almost zero, since the burning of wood, natural gas, coal and oil gradually increases the concentration of carbon dioxide in the atmosphere. And now fear is not so much cooling as mass melting at the poles of glaciers and an increase in sea level ...
Dry ice
In a liquid state, this gas is stored in high-pressure cylinders (approximately 70 Atm). If you open the valve of such a steel vessel, the snow starts to break out of the hole ... What kind of miracles? This fact is explained quite simply. Compression of carbon dioxide requires work that is substantially smaller in size than that necessary to expand it. To compensate for the deficit, CO 2 is rapidly cooled and turns into "dry ice". Compared to ordinary ice, it has a number of serious advantages: firstly, its evaporation occurs completely, without formation of residues. And secondly, the "refrigerating capacity" of dry ice per unit weight is twice as much.
Application
Carbon dioxide is often used as an inert medium in wire welding. However, at high temperatures, it decomposes with the release of oxygen oxidizing the metal. Therefore, deoxidizing agents such as silicon and manganese are added to the
welding wire . Carbon dioxide in spray cans is widely used in air guns and in aircraft modeling. Liquid gas is used as a fire extinguisher and for the manufacture of lemonade and soda. In addition, carbon dioxide CO2 is also used as a food additive (code E290). And as a well-known means for loosening dough. And besides, solid carbon dioxide is widely used for the conservation of food products.