Release that Witch Chapter 377: Oxygen and nitrogen

This experiment is not only of great practical significance, but also an excellent educational opportunity, so in addition to the participants Agatha, Silvie, James, and Cam Schuire, Roland also called the other members of Witch Union, Carter, Iron Axe, and Barov. In order to accommodate these 20 or so people, the test site was selected in the fifth laboratory with the largest space.

For the first attempt, the fractionation vessel was not too large, about one person tall and one meter in diameter, similar to a tower. The interior of the container is divided into three layers, the bottom layer is for air intake, and the upper two layers are for exhaust.

Before the separation started, Roland took a simple chemistry lesson for everyone, telling them what might happen, and by the way, asked a few small questions, let everyone find the answer by themselves, in addition to attracting the interest of the audience , Can also greatly enhance the effect of teaching, which is also a habitual skill of chemistry teachers.

"... In theory, when the Agatha lowers the internal temperature of the container, the air will gradually condense into a liquid, pass through the perforated partition, and drip to the lowest level. So when you observe the effusion at the bottom, tell us. "

Since it cannot be seen directly, it must be observed through a container by Silvie to describe the changes, so Roland is particularly detailed in this part.

Silvie nodded doubtfully, "Can you really see the liquid? Isn't it water vapor in the jar?"

"Don't worry, the liquid air is light blue, completely different from water vapor." Roland waved, "And at that temperature, water vapor has already solidified into ice crystals." Then he made a gesture toward Agatha, " So let's get started. "

"Wait ... don't you need to block this opening at the bottom of the container?" she asked.

"It will be blocked again later, otherwise there is too little air in the jar, and no obvious change will be observed." Because it is only an experiment, Roland chose the simplest method to inhale when the temperature in the tank is rapidly decreasing. The pressure then decreases, allowing the outside air to constantly pour into the tank. This is not worth the cost in conventional production, because the cold air will continue to be lost and energy is wasted, but Agatha uses magic power, and the cooling efficiency is far more than any refrigerator, so Roland is too lazy to prepare the air pump for inflation.

Agatha take a deep breath, press both hands on the fractionation column.

Between a few breaths, there is a howling sound in the intake duct, which is the sound of rapid air inrush. Layers of hoarfrost emerged at a speed visible to the naked eye around the nozzle, and continuously expanded. The moisture in the air quickly condensed at the overflowing low temperature and attached to the outer wall of the container. Anna turns black flames into silk threads, cleaning up these growing ice crystals.

After a while, Silvie said in surprise, "I saw liquid on the partition, but it was more white frost."

"The white frost may be the influx of water vapor or crystalline carbon dioxide," explained Roland. "Considering that the carbon dioxide content in the air is extremely low, most of it should be water vapor."

If the air is drawn into the fractionation tower, it must be dried before it is put into production. Otherwise, the layered board and exhaust holes will be easily blocked after the condensation of water vapor, which will reduce the production efficiency.

About half a quarter of an hour later, Silvie reported that the bottom of the container had been filled with blue liquid, and Roland only allowed Soraya to block the intake pipe and sealed it with a coating.

Next is the key warm-up.

According to the different boiling points of nitrogen and oxygen, nitrogen will take the lead to reach the boiling point, and will be turned into gas to escape upwards, so as to achieve separation. He does not remember the specific value of this temperature, and currently has no means to measure it, only rely on Agatha to grasp it. The specific performance is that gas is exhausted from the exhaust hole at the top of the fractionation tower, and the remaining liquid at the bottom will become more and more blue, which means that the purity of liquid oxygen is constantly improving.

Fortunately, Agatha is not unfamiliar with the control of magic power. She precisely adjusted the temperature drop to make it slowly rise. After a while, Silvie also observed the liquid level boiling. Bubbles began to appear in the coated tube that was passed into the water. The Cam quickly collected several bottles of gas using the drainage gas collection method.

"This is nitrogen?" Lily said with a lip, "I can't see anything at all."

"This is the first question I asked before," Roland asked, "how can I prove that it is different from air?"

"Ignite," Tilly took the lead in answer. "«Elementary Chemistry» said that combustion requires oxygen. If it is another gas, the burning wood block should be instantly extinguished."

"Cool it back into a liquid," Agatha said after thinking for a while, "Don't you say that nitrogen is colorless after liquefaction?"

"Or the remaining liquid in the container can be exported to prove that the latter is pure oxygen can also prove the diversity of air composition." Anna said.

The scene has completely become the stage for Xue Ba's performance. Test methods are proposed one by one and then discussed with each other. Only a few people's voices remain in the laboratory. Roland looked around for a week and found that Nightingale, Andrea, Macy and other dry witch, as well as City Hall Prime Minister and Chief Knight Carter, are all blank. First Army commanded Iron Axe to maintain an expression at all times, probably no matter what he said, he would nod and say yes.

Okay, Roland sighed at bottom of heart. It seems that this chemistry class is a little bit overdone.

If there are still people who can feel the joy of His Highness the Prince, I am afraid that only Cam Schuire and James are left.

"His Royal Highness, this is ... magic," exclaimed the young alchemist. "You have proved the correctness of «Elementary Chemistry». I am afraid that all alchemist would not have expected it, and the air everywhere is so complicated."

"With pure oxygen, can I observe more severe oxidation reactions? I have many experiments to do," said Cam excitedly.

Roland nodded, but suddenly another thought came to mind.

Nitrogen is the most important raw material for the artificial synthesis of ammonia. It can be reacted with hydrogen under the conditions of high temperature and high pressure plus catalyst to obtain ammonia. The latter can be used not only for the manufacture of nitrogen fertilizers, but also for the synthesis of nitrogen oxides. Nitric acid. However, if this process is to be realized, much work needs to be done, such as air pumps, vacuum gas storage tanks, and a series of complex reaction equipment. Even if White Paper can provide the function of a catalyst, it needs to be tested repeatedly.

Now that he has pure oxygen and pure nitrogen, why not directly produce nitric oxide?

It is true that the chemical industry chooses to use ammonia gas to produce nitric acid because the oxygen and nitrogen reactions are energy-absorbing reactions and cannot be carried out spontaneously. They require external energy supply. It is also the reason that soils are more fertile in places where thunder often occurs. Because of this, this method requires high equipment and high energy consumption, so it is not suitable for formal production.

If the production capacity is urgently needed, this production method has the highest efficiency, and even the catalyst is not needed. It only needs continuous discharge ... or other means to reach the high temperature generated by the arc.

Roland naturally thought of black fire.

The efficiency of black fire heating is not worse than that of arc, and the burden on Anna is extremely low. As long as the nitrogen and oxygen are purified, they are mixed and poured into a closed reactor in proportion, and nitric oxide can be continuously generated.

He decided to give it a try.

(To be continued.)

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