"All compounds of selenium and tellurium are toxic. Before doing the chemistry experiment, Liu Hualong reminded him seriously.

This is both a reminder and a knowledge point, and it is also part of the experiment. Liu Hualong and his classmates put on goggles, masks, and gloves, and the experiment began.

Like sulfur, the brother of the oxygen element, selenium and tellurium can form SeO2 and TeO2 when burned in the air.

Zizi!

The red selenium powder burned indulgently, and more than two dozen bewitching blue flames danced on the experimental table.

Lan Jie stared directly at him and Huang Yuhang's selenium blue flame, and he said stupidly: "It's so demonic, it's so beautiful, I really want to burn like this forever." ”

Chemistry is an experimental science, and many chemical experiments are beautiful and concrete.

Chemistry textbooks say that selenium burns to produce a blue flame, but only when you have burned selenium with your own hands can you understand and remember which blue color is after burning.

Although chemistry is a tool, chemical experiments are much more vivid than physical experiments.

Big Brother Physics is high up and not angry, and his experiments always make Ranger feel inviolable.

The status of chemical tools is not high, and its experiments come from the bones, and Ranger wants to infringe on it.

Selenium dioxide, the product of combustion, is a colorless crystal, which is very toxic. Lan Jie told Huang Yuhang: "Look with your eyes, wear gloves to touch, and wash your hands after the experiment." ”

"Hmm!" Huang Yuhang strictly followed the experimental procedures, and he asked curiously: "Can you take a little of the selenium compound out?"

"Brother, your idea is dangerous. Of course, Ranger didn't allow his lab partner to take the chemical poison out of the lab, and he couldn't afford it.

Huang Yuhang said with a smile: "I just asked casually, it's okay, it's okay, hehehe." ”

The next step is to dissolve selenium dioxide in water and add chlorine gas. This operation was carried out by Huang Yuhang and supervised by Lan Jie.

Huang Yuhang completed the experimental operation, and Lan Jie objectively commented: "Yuhang, you have done a good job, and your hands-on ability is not bad." ”

Huang Yuhang is very inspired: "Among so many subjects, my favorite is chemistry, and my favorite is to do chemistry experiments. ”

Liu Hualong, walking back and forth, closely monitoring the students' every move, said: "The substance in your beaker is a mixture of dilute selenic acid and dilute hydrochloric acid, which is oxidized by selenite acid and chlorine gas. Selenite acid is mainly oxidizing, and when it encounters stronger oxidants, it is reducing. Through this experiment, we observed that chlorine gas is more oxidizing, and chlorine gas can oxidize selenite to obtain selenic acid. ”

"Selenic acid and sulfuric acid have many similar properties, selenic acid is a non-volatile strong acid, has strong water absorption, can carbonize organic matter, and its oxidation is stronger than sulfuric acid. Hot concentrated selenic acid can dissolve metals such as gold, silver, and copper to form the corresponding selenate, and the mixture of hot selenic acid and concentrated hydrochloric acid is similar to aqua regia and can dissolve platinum. ”

"Platinum is a precious metal, and a mixture similar to aqua regia is more dangerous, so we can understand the theoretical knowledge points, and we don't need to prepare a mixture of hot selenic acid and concentrated hydrochloric acid. ”

When Liu Hualong explained this knowledge point, Huang Yuhang was fascinated by it, and he muttered to himself: "Selenium is a semiconductor material, and there is selenium in the photocell. It is not difficult to prepare chlorine, and the electrolysis of salt water is complete. With chlorine, hydrochloric acid can be obtained in various concentrations. Therefore, my raw materials are simple and easy to obtain, photocells, salt, and distilled water, which can be bought in regular stores, and will not attract special attention from the clerks. ”

Lan Jie looked at Huang Yuhang with admiration: "Brother, it seems that you really like chemistry, and your level of chemical theory is not low, and you have a certain degree of experimental hands-on ability and divergent thinking." So what did you use the liquid like aqua regia for?"

Huang Yuhang said with certainty: "Of course, it is used for scientific purposes!"

"That's good, that's good. Lan Jie was very pleased.

The experiment continued, and under the careful guidance of Mr. Liu, the students prepared sodium selenite.

There are knowledge points here, Liu Hualong said: "Sodium selenite is highly toxic, and one gram of oral administration in adults can cause death, but under the supervision of professional physicians, oral administration of an appropriate amount of sodium selenite can prevent and treat Keshan disease, and the clinical effect is good and safe." Keshan disease is now largely gone, sodium selenite has played a role in medicine, and it is currently mainly used for industrial purposes. ”

"Well, remember!" Huang Yuhang stared at the white powdered sodium selenite, his eyes flashing with a frenzied light. He likes the knowledge points with strong practical skills, and can quickly understand and remember the relevant knowledge points.

Unlike sulfuric acid and selenic acid, telluric acid is a weak acid.

Because of the time relationship, Mr. Liu did not instruct the students to prepare telluric acid, and the relevant theoretical knowledge should be taught, Liu Hualong said: "High school chemistry is mainly inorganic, although there are only four oxygen elements, but they are very important. I have talked too much about oxygen and sulfur, and selenium and tellurium should also attract the attention of students. Due to the weak acidity of telluric acid and the ability to form hexabetical substances, the chemical formula of telluric acid is not H2TeO4, but H6TeO6 or Te(OH)6. X-ray studies have proved that the six OH- arrangements within the tellurium acid molecule form an octahedral structure around the tellurium atoms......"

Huang Yuhang likes chemistry, and what he likes is the ever-changing chemical phenomena, as well as the colorful, mysterious and magical specific properties of various elements and compounds.

What annoys him the most is the microscopic structure that is highly theoretical and detached from real life, this orbit and that track, hexahedron, octahedron, these things can't be seen or touched, and they are very boring, and they can't be applied to real life at all.

But now, Huang Yuhang listened very carefully to Mr. Liu's talk about microstructure.

The essential reason for the emergence of macroscopic phenomena is micromanipulation at the micro level. Huang Yuhang was sublimated, and after the chemistry experiment class, he humbly asked Lan Jie for the microscopic knowledge of oxygen elements.

Those who should have transferred to the class have all been transferred, and they are about to enter the third year of high school, and there are no more students copying homework in the second and third classes, only students who learn from each other.

Lan Jie saw Huang Yuhang's strengths, and the student had a persistent preference for chemistry.

Even if some disciplines are tools, those who devote themselves to one subject deserve respect.

Lan Jie doesn't think of himself as a coaxing father, nor does he see Huang Yuhang as a humble brother, he just shares his understanding of chemistry with Huang Yuhang: "The structure of selenium dioxide is very interesting, it is composed of an infinitely long chain of selenium dioxide and bridging oxygen atoms. In fact, I have been thinking that the microstructure determines the macroscopic properties, so which microstructure determines which macroscopic properties are worthy of further study. Chemistry is a very interesting subject. Astronautics, so you're going to fill in the chemistry major?"