The chemical properties of nitrogen are generally stable and can be used as a protective gas for general reactions, but it can also chemically react with some substances under certain conditions, such as synthesizing ammonia with hydrogen under high temperature and high pressure, and reacting with oxygen to form under discharge conditions. Nitrogen oxides can also burn some active metals to form metal nitrides, such as Mg3N2, Na3N, etc.

The chemical properties of nitrogen

Positive nitrogen is acidic and negative nitrogen is basic.

Because the triple bond energy in nitrogen molecule is very large, it is not easy to be destroyed, so its chemical properties are very stable. Only under the conditions of high temperature and high pressure and the presence of catalysts, nitrogen components can react with hydrogen to form ammonia. At the same time, due to the relatively stable chemical structure of nitrogen molecules, the C22- and nitrogen molecular structures in cyanide ions CN- and calcium carbide CaC2 are similar.

There is a nitrogen-nitrogen triple bond in the nitrogen molecule, and the bond energy is so large (941 KJ/mol) that only 0.1% dissociates when heated to 3273K. The nitrogen molecule is the most stable among the known diatomic molecules. Nitrogen is the isoelectronic body of CO and has many similarities in structure and properties. Different reactive metals react differently with nitrogen. It can be directly combined with alkali metals at room temperature; it generally needs to be combined with alkaline earth metals at a high temperature; and the elemental reaction with other group elements requires higher reaction conditions.

The three major chemical properties of nitrogen

1. Reacts with oxygen

N2+O2=discharge=2NO

Nitric oxide quickly combines with oxygen to form nitrogen dioxide

2NO+O2=2NO2

2. React with hydrogen

N2+3H2=2NH3 (high temperature and high pressure catalyst)

Description: Under the conditions of high temperature, high pressure and the presence of a catalyst, N2 and H2 can be directly combined to generate ammonia (NH3) and release heat; at the same time, NH3 will also be decomposed into N2 and H2, this reaction is a reversible reaction.

This reaction principle is used in industry to synthesize ammonia.

3. Reacts with reactive metals

Nitrogen is inactive and rarely reacts with other substances. But there are also special ones, such as reacting with metal magnesium.

The reaction equation is: 3Mg+N2=ignite=Mg3N2(magnesium nitride)

Nitrogen atoms have strong non-metallic properties, and there are covalent triple bonds in nitrogen molecules, and the bond energy is large, so the chemical properties of nitrogen are inactive. But at high temperature, the covalent bond is broken, and nitrogen can react with many substances. The above is just a list of common nitrogen reactions in junior high school chemistry. Although nitrogen knowledge is not introduced much in textbooks, because it is the main component of air and has the exact opposite chemical properties to oxygen, in recent years, questions related to testing nitrogen knowledge have appeared frequently. Next, let's review the chemical properties of nitrogen through a test question.

The use of nitrogen

1. Due to the chemical inertness of nitrogen, it is often used as a protective gas, such as: fruits, food, bulb filling gas.
2. In order to prevent certain objects from being oxidized by oxygen when exposed to the air, filling the granary with nitrogen can make the grain not moldy or sprouted, and can be stored for a long time.
3. Liquid nitrogen can also be used as a deep cryogen. As a cryogen, it is often used in hospitals to remove spots, bags, beans, etc., that is, to freeze the spots, bags, beans, etc., but it is prone to scars, so it is not recommended to use.
4. High-purity nitrogen is used as the carrier gas for instruments such as chromatographs. Used as a bright annealing shielding gas for copper tubes. Used as laser gas for laser cutting machine together with high-purity helium and high-purity carbon dioxide.
5. Nitrogen is also used as a protective gas for food preservation.
6. In the chemical industry, nitrogen is mainly used as protective gas, replacement gas, cleaning gas, and security gas. Used as protective gas for aluminum products, aluminum profile processing, aluminum thin rolling, etc. Used as a protective gas for reflow soldering and wave soldering to improve soldering quality. It is used as a protective gas in the production process of float glass to prevent oxidation of the tin bath.