Sodium carbonate, commonly known as soda, soda ash, washing alkali, chemical formula: Na?CO?, under normal circumstances, it is a white powder, and it is a strong electrolyte. The density is 2.532g/cm3, the melting point is 851 °C, soluble in water, and has the universality of salt.

The sodium carbonate that is present in nature, such as salt water lakes, is called trona. This is currently the main source of sodium carbonate in Qin. But production is very limited. This is also one of the reasons why glass, textile, chemical and other related industries cannot develop rapidly at present.

It can be said that the development of sodium carbonate now has signs of restricting the development of chemistry in Qin.

Sodium carbonate is produced in the laboratory, mainly by the reaction of sodium hydroxide and carbon dioxide.

As early as 1791, the ancients began to use salt, sulfuric acid, coal, and limestone as raw materials to produce sodium carbonate, which was the Lüblanc method. This method is gradually replaced by the Solvay method due to insufficient utilization of raw materials, poor labor conditions, and poor product quality.

Solvay method, in 1859, Belgian Solvay, using salt, ammonia, carbon dioxide as raw materials, precipitated sodium bicarbonate from the solution at room temperature, heated it, that is, decomposed into sodium carbonate, people call this method Soxhlet alkali method, this method has been used to this day.

Hou Debang method In 1943, the Chinese Hou Debang returned from studying abroad, and he combined the national conditions of salt shortage in Chinese mainland to improve the Solvay method, combining the two major industries of soda ash and synthetic ammonia, and producing sodium carbonate and fertilizer ammonium chloride at the same time, which greatly improved the utilization rate of salt, which was the alkali method for Hou's.

Only the last two of the four methods can be employed. Solvija and Hudbangfa. But two require another chemical, ammonia.

Camel dung was a common fuel in the desert, and even the divine Zeus had to condescend to it. As a result of the long-term burning of camel dung, the walls and ceilings of the temples of Zeus-Amor were covered with a layer of soot. The soot contains white crystals like salt, and from time to time it emits a pungent smell. Locals call this white crystal salammonic. In 1774, the British chemist Priestley collected this pungent gas separately and studied it, and he found that this gas was soluble in water and showed alkalineness, so he called it "alkaline gas". However, the term was not accepted by the chemical community, and eventually the gas was given the name "Am-monia" from the source of the gas, the salt of the god Amour. This is what we call "ammonia" today.

If Shangwen wants to make ammonia, he can only use this crystalline and calcium hydroxide heating. Think of unpleasant smells. Shang Wen's stomach felt unappetizing. But do it anyway. But before that, I also had to make a "gas mask." ”

And this crystalline can only be collected from feces. I guess some people don't know yet. Saltpeter is not much in the East, but it is quite frequent in Europe. These were the reasons for the development of chemistry in Europe, but after they discovered the power of muskets, they developed rapidly. But saltpeter is in high demand. It was later discovered that human and animal excrement contained nitrate, so it was collected in large quantities. Even human excrement is strictly controlled. This can be regarded as a contribution to chemistry.

Human ingenuity is always quick to find another way to obtain it after the lack of one item.

Shangwen needs a large amount of activated carbon. At the same time, people should pay attention to the crystals that form after the excrement is dried. It takes time.

One night, Shang Wen went in and out, spent a night of time, and finally only made a few pieces of furniture. Shang Wen lay on the leather sofa that had just been made in a daze.

Yingyu slept very comfortably until the sun rose high.

Yingyu stretched her waist widely, feeling that she had never slept in such a comfortable bed, and she really came here by herself.

Yingyu walked out of the outhouse and found that there were a few strange things in the room at once.

"Hey, hey." Yingyu woke up Shang Wen with curiosity.

Shang Wen stayed up all night, and it was the most sleepy time, Shang Wen closed his eyes and said, "What's the matter?" ”

"What is this, why is it so strange. And this one you're sitting on, what is this? Yingyu asked repeatedly.

"The sofa, the rest is all furniture." Shang Wen replied simply.

"Sofa. Couch. What is Sofa? Yingyu asked.

"A high-class chair." Shang Wen said impatiently.

"Chairs?" Yingyu asked, "See for yourself." I'm sleepy. Shang Wen said and turned around.

"Hey. Ay. Yingyu shouted loudly.

"Hmph." Yingyu turned around and snorted. So he went to check it out for himself.

And this night, what happened was far beyond Shang Wen's imagination. It had been snowing all night in the north. The snow is light in the morning. But it didn't stop. The snow overnight was very thick and high. No human leg can be opened.

"Why is it snowing so much?" Meng Tian began to inspect the camp early in the morning.

"General, many people who went out to stand guard froze to death." A close guard said.

"What?" Meng Tian was surprised.

"Oh no, General. Oh no, General. Tu Sui shouted loudly.

"What's wrong with General Tu?" Meng Tian immediately regained his composure and asked.

"I don't know what's going on, a lot of soldiers are dying in the shacks." Tu Sui said.

"How many?" Meng Tian asked.

"There are already one or two hundred." Tu Sui said bitterly.

"What, how come there are so many." Meng Tian asked.

"Hey." Tu Sui still looked distressed. These musketeers are all Tu Sui's treasures. These musketeers were well-trained and were the first musket regiment in the Great Qin State. Now so many died without a war. So far, one of them has died here in a daze.

"What's the reason, have you found out the situation?" Meng Tian asked.

Tu Sui shook his head.

"Let's go, let's see." Meng Tian said.

Shacks, the cold in the north came early. And unusually cold. The tents brought by the Qin army were simply unable to defend against them. Later, the Qin army saw the Huns and Hu people digging pits on the spot and then making shacks. Then I learned. Unexpectedly. The shack was warmer than a tent, so word of the idea spread quickly.

Yesterday it was very cold, and there was a lack of charcoal in the north, but Qin Jun found that the coal from the iron factory could be used for heating, so he used it. In the sealed shack, Qin Jun also specially opened a hole in it in order to ventilate.

But yesterday it was windy. The wind is still strong. The rapid air flow makes it impossible for the air flow in the shack to flow out, resulting in insufficient combustion of coal, producing a large amount of carbon monoxide, which cannot be removed, causing the concentration to rise sharply. A large number of Qin soldiers died in a coma in this way.