What properties are used by using nitrogen as a protective gas?

No new substances are produced The reason for using nitrogen as a protective gas is that nitrogen is chemically inactive.

It's not easy to react with other substances, so it's like something is surrounded by a layer of nitrogen, and the other substances around it are outside the nitrogen layer.

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

at standard atmospheric pressure.

, when nitrogen is cooled to, it becomes a colorless liquid, and when cooled, liquid nitrogen.

Turns into a snow-like solid. Nitrogen is often used to make preservatives.

Under high-temperature and high-energy conditions, it can be used to produce new substances that are useful to human beings. Nitrogen is a colorless and odorless gas under normal conditions, with a melting point of 63K, a boiling point of 77K, and a critical temperature of 126K, which is difficult to liquefy. Solubility.

Very small, at atmospheric pressure at 283 k, one volume of water can dissolve the volume of nitrogen.

a. Nitrogen as protective gas is to use the stability of nitrogen, which is a chemical property, so the choice is wrong;

b. The use of dry ice as a refrigerant is the sublimation of dry ice, which is a physical property, so the choice is correct;

c. Hydrogen as fuel is the flammability of hydrogen and belongs to chemical properties, so the choice is wrong;

d. The use of oxygen in steelmaking is to use the combustible properties of oxygen, which is a chemical property, so the choice is wrong; Therefore, choose B

Pick B because it uses dry ice for sublimation.

Nitrogen can be used as a protective gas.

Analysis: Chemical properties of nitrogen.

Not reactive, often filled with nitrogen in welded metal or light bulbs. There are about 4,000 trillion tons of gas in the atmosphere, of which nitrogen accounts for 78%. Nitrogen is slightly soluble in water and alcohol.

It is non-flammable and is considered a asphyxiating gas (i.e., breathing pure nitrogen deprives the body of oxygen).

Nitrogen is found in many complex organic molecules, including proteins and amino acids present in all living organisms.

Physicochemical properties of protective gases in nitrogen:

There are about 40 million tonnes of gas in the atmosphere, of which nitrogen accounts for 78%. Nitrogen is slightly soluble in water and alcohol. It is non-flammable and is considered a asphyxiating gas (i.e., breathing pure nitrogen deprives the body of oxygen).

Although nitrogen is considered an inert element, it forms some very active compounds.

It can be used as a diluent.

It also controls the natural rate of combustion and respiration, which will be faster at higher oxygen concentrations. Nitrogen is soluble in water and alcohol, but it is basically insoluble in most other liquids. It is essential in life, and its compounds can be used as food or fertilizer.

Nitrogen is used in the manufacture of ammonia and nitric acid.

Nitrogen is basically an inert gas at ambient and moderate temperatures.

As a result, most metals are easy to handle with it. At elevated temperatures, nitrogen can be aggressive to metals and alloys.

It is mainly to expel oxygen and protect the normal operation of the reaction, especially the free radical reaction.

Oxygen needs to be isolated, protected with nitrogen.

Nitrogen is a colorless and odorless gas under normal conditions, with a melting point of 63 K, a boiling point of 77 K, and a critical temperature.

It is a version of 126 k, which is difficult to liquefy. Solubility.

Very small, at atmospheric pressure at 283 k, one volume of water can dissolve the volume of nitrogen.

Chemical properties. It is very stable, and only under the conditions of high temperature and high pressure and the presence of a catalyst, the nitrogen component can react with hydrogen to form ammonia. At the same time, due to the relatively stable chemical structure of the nitrogen molecule, cyanide ions cn- and calcium carbide.

The C22- and nitrogen molecules in CAC2 are similar in structure.

Although nitrogen is more abundant in the atmosphere than oxygen, because of its inactive nature, people only know nitrogen after understanding oxygen. However, it was discovered before oxygen.

Prevents oxidation. Nitrogen, on the other hand, is relatively stable and easy to obtain, so it often acts as a protective gas.

Prevents air from participating in the oxidation of organic matter.

1. It is stable in nature and does not react chemically with food.

2. Non-toxic. Third, the first extensive, the market value is cheap.

Nitrogen, which is usually a colorless and odorless gas, is generally less dense than air. Nitrogen is one of the main components of air. At standard atmospheric pressure, nitrogen becomes a colorless liquid when cooled to a point and liquid nitrogen becomes a snow-like solid when cooled to a point where it is cooled.

Nitrogen is chemically inactive, and it is difficult to react with other substances at room temperature, so it is often used to make preservatives. However, under high temperature and high energy conditions, it can undergo chemical changes with certain substances and be used to make new substances useful to human beings.

The chemical properties of nitrogen are very inactive, only under high temperature, high pressure or discharge, and it is non-toxic and non-polluting, so nitrogen can be used as a protective gas for burning food under conventional circumstances.

1. It is stable in nature and does not react chemically with food.

2. Non-toxic. Third, the first extensive, the market value is cheap.

Because nitrogen is chemically stable, it does not easily react with other substances under normal circumstances, and therefore does not react with food and spoil.

It is also important to note that nitrogen itself is non-toxic and harmless, and does not directly harm the human body. Otherwise, even if the food does not react with it and spoils, it will poison the person ...... death

The chemical formula of nitrogen and helium is n 2 respectively, he can be used as a protective gas because the chemical properties are not active, and they can be used as protective gas, so the answer is: n 2 , he; The nature of the study is very stable.

a. Nitrogen do.

Protective gas. It is the use of the stability of nitrogen, which is a chemical property, so the option is wrong; b. Dry ice.

Used as a refrigerant, dry ice is endothermic sublimation, which is a physical property, so the choice is correct;

c. Hydrogen is hydrogen as fuel.

flammability, which is a chemical nature, so the option is wrong;

d. Oxygen is used in steelmaking by using oxygen.

flammability, which is a chemical property, so the option is wrong; Therefore, choose B