A chemistry question about liquid nitrogen

1.Large quantities of liquid nitrogen have special storage places. When you need to get it, use a dewar to get it.

Even though you say you only need a few hundred milliliters, but you think, liquid nitrogen is 77k, and it first has to cool the devapine to 77kDuring this cooling process, liquid nitrogen vaporizes in large quantities.

2.It is not possible to pack it in an airtight container. How powerful. It depends on how well you seal the container. The better the seal, the more powerful it is. Hahaha.

3.Generally, after the liquid nitrogen is retrieved with a dewar, it can be covered with foam or aluminum foil. No need to plug it tightly. In this way, liquid nitrogen can also be stored for at least half a day.

Because the specific heat of liquid nitrogen is low, a small amount of liquid nitrogen splashes on the hand, which is a small pain or two. However, it is safe to use liquid nitrogen for the first time, and it is best to use it under the guidance of an experienced person.

I remember that liquid nitrogen could be temporarily put in a warm pot... It's still a special tank, it's not very big.

Liquid nitrogen itself does not undergo a combustible-like chemical reaction, but if liquid nitrogen is placed in a sealed tank, it can occur as the nitrogen gradually becomes gaseous and the volume increases.

Here are my personal thoughts:

1。At room temperature, you need a special tank, and of course if you can make the ambient temperature very low (below the boiling point of liquid nitrogen), you don't need it.

2。As long as the strength of the sealed tank can resist the high pressure of liquid nitrogen, it will not be **, which can be calculated according to the ambient temperature.

3。At room temperature, liquid nitrogen volatilizes quickly.

**Mainly because the gas in the sealed space expands violently, and the pressure is greater than the pressure resistance of the sealed tank.

The mistake in using liquid nitrogen is to use more liquid nitrogen on top of flammable materials, which will not cause flammable materials to catch fire.

How to use it correctly:

Generally speaking, when flushing liquid nitrogen, the evaporation loss can only return to the steady state after 48 hours, and the time required for the excellent liquid nitrogen tank to return to the steady state can be reduced to 12 hours, and the evaporation loss can be reduced by 50%. We know the characteristics of liquid nitrogen and the brief structure of the liquid nitrogen tank, so that we can use it correctly and give full play to its performance. The main points of use are summarized below:

First, there should be a special person responsible for management, use and maintenance. If multiple liquid nitrogen tanks are stored in a closed room, the evaporated nitrogen will remain in the room, resulting in a hypoxic state, and suffocation may occur. The operation of the liquid nitrogen tank should be handled gently to avoid collision with other objects, because the liquid nitrogen tank becomes a high vacuum state by exhaust, and the pressure of the atmosphere in the inner and outer tanks is considerable, taking DR-10 and DR-30 as an example, the pressure on the outer tank is about 4O kg to 9O kg, although.

However, it is made to withstand three times its own weight, and it must be handled with great care and must not be dropped or collided.

2. When the liquid nitrogen tank is filled for the first time, or the inside of the liquid nitrogen tank is in a dry state, it is necessary to check the fierce silver bush first to see if there is a depression or other abnormal conditions on the outside of the tank. Whether there are foreign objects in the tank and whether the base is exactly fixed. If these conditions are good, the filling of liquid nitrogen can be started, and it is advisable to do it in a well-ventilated area, generally outdoors.

If it is carried out indoors, doors and windows should be opened to maintain good ventilation. One of the filling methods of liquid nitrogen is the pressure injection method, which is to open the liquid valve from a large liquid nitrogen container and connect it to a flexible hose.

The liquid nitrogen tank is filled with liquid nitrogen. Another is to directly use the funnel pouring method, which should pay special attention to the end of the funnel slightly away from the neck tube, so that the gas of liquid nitrogen evaporation can escape smoothly from the gap between the funnel and the container, otherwise the liquid will overflow from the funnel, not only will increase the loss of liquid nitrogen, and frostbite accident will occur. Fill the liquid nitrogen slowly, inject a small amount first, then stop for a few minutes to cool it and then gradually fill it up to the specified capacity

3. When taking and placing the bucket, the bucket should be slightly raised, so that the bottom of the bucket leaves the base, and then the bucket is moved parallel to the tank of the bucket, and the natural upward lift, the action should be calm and fast, not to use force, so as not to twist or break the handle, when taking and placing the bucket, we should also pay attention to avoid rubbing the inner wall of the neck tube, so as not to damage the neck tube, the handle should be placed in the indexing circle, and the cover plug should be covered to avoid more nitrogen.

Fourth, the cycle of liquid nitrogen supplementation. How much should the liquid nitrogen be reduced before replenishing? In general, it is better to replenish liquid nitrogen residue when it is equal to the full volume of one container or only enough for one week.

To replenish the capacity, place the liquid nitrogen tank on the scale and weigh it. The weight of one liter of liquid nitrogen is kilograms plus the weight of the tank to obtain the weight of the tank when it is full, minus the existing weighing weight, which is the capacity that should be supplemented.

Liquid nitrogen is produced in an air separation plant by air liquefaction and distillation, where the air is liquefied at high pressure, the mixed components are rectified, and then the nitrogen is used as a cryogenic liquid**.

Liquid nitrogen is an inert, colorless, odorless, non-corrosive, non-flammable, extremely low temperature gas, nitrogen constitutes the great bend of the atmosphere, nitrogen is inactive, does not support combustion, but nitrogen is a necessary element to sustain life.

Liquid nitrogen, with the chemical formula N2, is a liquid nitrogen that is colorless, odorless, non-corrosive, non-flammable, and has a very low temperature.

Liquid nitrogen at atmospheric pressure, liquid nitrogen temperature of 196, 1 cubic meter of liquid nitrogen can expand to 696 cubic meters of pure gaseous nitrogen at 21 °C, should be stored in a cool, ventilated warehouse, ** contact with liquid nitrogen can cause frostbite.

Danger: Invasion route: Inhalation.

Health Hazards: **Exposure to liquid nitrogen can cause frostbite. If the nitrogen produced by vaporization at atmospheric pressure is excessive, the partial pressure of oxygen in the air can drop, and in extreme cases, it may cause hypoxic suffocation.

Explosion hazard: This product is non-flammable and not easy to explode.

Liquid nitrogen laxative treatment method:

When the concentration of inhaled nitrogen is not too high, the patient initially feels chest tightness, shortness of breath, and weakness; This is followed by irritability, extreme excitement, running around, shouting, trance, and unsteady gait, which is called "nitrogen tincture", and can enter a state of lethargy or coma. When inhaled at high concentrations, patients can quickly fall unconscious, die due to respiratory and cardiac arrest.

1. Quickly evacuate personnel from the leakage and contamination area to the upwind of the cracked search, and set up an isolation area to strictly restrict access and access.

2. Notify the fire department and related units.

3. Emergency responders wear self-contained positive pressure respirators, cold-proof clothing, and cold-proof gloves.

4. Avoid leaking liquid into the basement or other enclosed working space, and notify the relevant departments immediately if it cannot be avoided.

5 Do not come into direct contact with spills.

Medical applications of liquid nitrogen.

Abstract:Liquid nitrogen** is a colorless, odorless, non-corrosive, non-flammable, extremely low temperature liquid in the atmosphere. At atmospheric pressure, the boiling point of nitrogen is that liquid nitrogen can be obtained at higher temperatures if pressurized.

In industry, liquid nitrogen is obtained by air fractionation. After purifying the air, it is liquefied under pressure and cooling, and separated by the different boiling points of each component in the air. 1. What is the temperature of liquid nitrogen?

The chemical formula of liquid nitrogen is LN2, which is the liquid form of nitrogen at low temperatures. The boiling point of liquid nitrogen is -196 degrees Celsius, and liquid nitrogen will be formed at temperatures below minus 196 degrees Celsius at normal atmospheric pressure.

2. Is liquid nitrogen a gas or a liquid.

The liquid nitrogen in the liquid nitrogen tank is in a liquid state below -196 degrees Celsius, once it exceeds -196 degrees Celsius, it will boil into a gas state, and once it is lower than -196 degrees Celsius, it will appear to freeze in a solid state, so the state of liquid nitrogen must be controlled within a certain temperature, so as to better maintain the characteristics of liquid nitrogen and meet the normal storage activity of biological cells.

3. How liquid nitrogen is produced from the nucleus of the orange cavity.

In industry, it is generally pressurized at low temperatures to convert the air into liquid air and then evaporate. Since the boiling point of liquid nitrogen is -196 degrees Celsius, which is lower than that of liquid oxygen, nitrogen first evaporates from the liquid air.

After collecting nitrogen, it is then cooled and pressurized to increase the boiling point of nitrogen liquefaction, and liquid nitrogen can be obtained. This step is dangerous, and liquid nitrogen can only be obtained under the safe operation of laboratories and industrial facilities. It is not recommended to make liquid nitrogen by yourself in ordinary life.

4. Precautions for liquid nitrogen operation.

1. Closed operation, providing good natural ventilation conditions.

2. The operator must be specially trained and strictly abide by the operating procedures.

3. It is recommended that the operator wear cold-proof clothing and cold-proof gloves. Prevent gas leakage into the workplace air.

4. Light loading and unloading during handling to prevent damage to cylinders and accessories. Equipped with leakage emergency response equipment.