What is the use of medical nitrogen?

Nitrogen with the chemical formula N2 is usually a colorless and odorless gas, which is usually less dense than air. Nitrogen accounts for 78.08% (volume fraction) of the total atmosphere and is one of the main components of air.

Use:

1, nitrogen is mainly used for synthetic ammonia, and the reaction formula is (under the conditions of high pressure, high temperature and catalyst. The reaction is reversible) or an important raw material for synthetic fiber (nylon, acrylic fiber), synthetic resin, synthetic rubber, etc. ?

2. Nitrogen is a nutrient element and can also be used to make fertilizer. For example: ammonium bicarbonate NH4HCO3, ammonium chloride NH4Cl, ammonium nitrate NH4NO3, etc.

3, commonly used as protective gas, such as: fruit, food, light bulb filling gas. In order to prevent some objects from being oxidized by oxygen when exposed to the air, filling nitrogen into the granary can keep the grain from mildew and germination for a long time.

4. Liquid nitrogen can also be used as a deep refrigerant. As a refrigerant, it is often used in hospital freckle, steamed stuffed bun and bean surgery, that is, frozen spots, steamed stuffed bun and beans, but it is easy to scar and is not recommended.

5. High purity nitrogen is used as the carrier gas of chromatograph and other instruments. Used as protective gas for bright annealing of copper tubes. Used as laser gas of laser cutting machine together with high-purity helium and high-purity carbon dioxide.

6. Nitrogen is also used as a protective gas for food preservation.

7. In chemical industry, nitrogen is mainly used as protective gas, displacement gas, washing gas and safety gas. Used as protective gas for aluminum products, aluminum profile processing, aluminum thin rolling, etc.

8. Used as shielding gas for reflow soldering and wave soldering to improve welding quality. Used as protective gas in float glass production to prevent tin bath oxidation.

Extended data:

Physical properties of nitrogen:

Nitrogen is a colorless and odorless gas under normal circumstances, accounting for about 78% of the air volume (oxygen is about 2 1%). Melting point 63 K, boiling point 77 K, critical temperature 126 K, not easy to liquefy. The solubility is very small. Under the atmospheric pressure of 283 K, integrated water can dissolve 0.02 volume of nitrogen.

Nitrogen is a gas that is difficult to liquefy. Nitrogen will liquefy into colorless liquid at extremely low temperature, and white crystalline solid will be formed when the temperature is further lowered. In production, nitrogen is usually filled in black steel cylinders.

Chemical properties of nitrogen:

From the oxidation state-Gibbs free energy diagram of nitrogen, it can also be seen that N2 molecule with oxidation number 0 is at the lowest point of the diagram except NH4+ ion, which indicates that N2 is a thermodynamically stable structure compared with other nitrogen compounds with oxidation number. The values of various nitrogen compounds with oxidation number between 0 and +5 are above the connecting line between HNO3 and N2 (dotted line in the figure). Therefore, these compounds are thermodynamically unstable and easy to disproportionate. One of the molecules with lower molecular weight than N2 in the figure is NH4+ ion.

Positive nitrogen is acidic and negative nitrogen is alkaline.

Because the triple bond in nitrogen molecule is very strong and difficult to be destroyed, its chemical properties are very stable. Only under the conditions of high temperature and high pressure and the presence of catalyst can nitrogen components react with hydrogen to produce ammonia. At the same time, because the chemical structure of nitrogen molecule is relatively stable, the molecular structure of cyanide ions CN- and C22- is similar to that of nitrogen in calcium carbide CaC2.

There are nitrogen-nitrogen triple bonds in the nitrogen molecule, and the bond energy is so great that only 0. 1% dissociates when heated to 3273K, and the nitrogen molecule is the most stable among the known diatomic molecules. Nitrogen is an isoelectronic body of CO, which has many similarities in structure and properties.

Metals with different activities react differently with nitrogen. Directly combine with alkali metal at normal temperature; With alkaline earth metals-generally need to be combined at high temperature; The reaction with other group elements simple materials requires higher reaction conditions.

References:

Baidu encyclopedia-nitrogen