Otaku Engineer in Great Tang Dynasty Chapter 849: Examination (below)!

"Question 1: Put a certain amount of anhydrous alcohol and oxygen in a completely closed container to ignite, the reaction produces carbon dioxide, water vapor and an unknown substance X. The mass of the substance before and after the reaction is measured. Water ethanol is 4.6g and 0g, oxygen is 8g and 0g, carbon dioxide is 0g and 4.4g, water is 0g and 5.4g, substance X is 0g and mg, the value of m is ______, and the molecular formula of substance X is ______ ."

(Note, in order to facilitate future teaching, Li Zexuan unified the unit at the forefront of the four textbooks, but this is only a written unity, and the actual unity will depend on the joint efforts of the teachers and students of Yanhuang Academy. Up)

Although I have been prepared for the difficulty of the exam, the first question is such a practical application plus calculation question, which still surprised Wang Ji. Shouldn't I first test the basic concepts?

This question is mainly about the law of conservation of mass in the process of chemical reactions. After a little extrapolation, he got the correct answer.

At this time, he couldn't help but feel fortunate in his heart. Fortunately, he has also studied new maths. Otherwise, how could it be so fast?

"The second question, put two glass cups A and B on two scales. The glass cups contain dilute sulfuric acid with different qualities but both contain 9.8g sulfuric acid. It is known that the glass cup A is better than the glass glass B. After the reaction is completed and the balance is kept in balance, the maximum quality difference between A and B glass before the reaction is OR."

(Note, balances existed in ancient times. They were produced earlier. By the late Spring and Autumn Period, the manufacturing technology of balances and weights was quite sophisticated. Bamboo was used as beams, and silk threads were used as ties. Duange hung a copper plate. Later, because the balance was troublesome to weigh, it was changed to "quan", and the balance was used when weighing small objects)

Although Wang Ji has never seen such things as sulfuric acid and zinc, he still knows their chemical reactions by heart, but how does this question look more perverted than the previous one? You should also use the knowledge of equations in new arithmetic, right?

Wang Ji's heart suddenly began to gallop, and it was also due to his research on new mathematics. Otherwise, even if his "Chemistry" textbook was memorized and understood, he would have to kneel when he encountered this test paper. !

Although Wang Ji has some research on new mathematics, he is far from proficient. After solving one problem, he is already sweating profusely, just like running ten miles.

After finishing the second question, Wang Ji couldn't help but raise his head. With his somewhat resentful eyes, he glanced at Li Zexuan and said to his heart: Does the old man have hatred with your kid? It's just a question. Is it necessary to make it so difficult?

It's not that he is hypocritical, but in a strict sense, Li Zexuan's question is somewhat "super-class". Moreover, all test questions are biased towards practical applications. It is basically difficult to get good results just by reading books!

"Oh, no matter how difficult it is, you have to fight! You can't lose in this bet!"

Although he has only stayed in Yanhuang Academy for more than a month, Wang Ji feels that he has completely liked it here. Not only does he like the environment, facilities, wine and food, but also the atmosphere of Yanhuang Academy. Positive, united and forge ahead atmosphere!

He doesn't want to leave!

The desire to survive, this is another desire to survive!

The strong desire to survive has made Wang Ji's mind more sober than ever, and his thinking has become more active. Although most of the test papers are questions he has never seen before, he can always find ideas for solving problems. In this way, he broke through all the way, half an hour before the end of the exam, Wang Ji finally came to the last question.

This is a question and answer, "37.2g of a mixture consisting of sodium carbonate, sodium bicarbonate, calcium oxide and sodium hydroxide, dissolved in enough water and fully reacted, the calcium ion, carbonate ion, hydrogen carbonate All the root ions are converted into precipitation, and the water in the reaction vessel is evaporated to dryness, and finally 39.0g of white solid is obtained. What is the mass of sodium carbonate in the original mixture?"

The sequelae of breaking through all the way and performing supernormal performance is brain pain. At this moment, after seeing this last big issue, Wang Ji felt that his head was about to explode! Because many substances in this question can interact with each other.

In fact, for Li Zexuan, who has received modern higher education, this question is not difficult at all, because it involves multi-step reactions and multi-substance cross-reactions (calcium oxide reacts with water to form calcium hydroxide, Calcium hydroxide can react with sodium carbonate and sodium bicarbonate). Just combine multiple chemical reaction formulas into one and balance them. After obtaining a general chemical reaction formula, the whole problem will be solved. There is no difficulty.

But for Wang Ji, a beginner of "Chemistry", he obviously does not know this method, so what should he do? He must take this question!

After thinking about it for a long time, Wang Ji didn't think of a very clever and simple way. He gritted his teeth and turned his mind. He decided to use the most stupid way to solve this problem, that is, to use the equation method.

"Isn’t there more unknowns? It’s okay, solve! I don’t believe it, I can’t figure it out today~!"

Wang Ji said viciously in his heart.

At the same time, he couldn't help feeling, whether this is the "Chemistry" exam or the "Mathematics" exam? He used three draft papers for calculations!

Fortunately, he used a pencil given by Li Zexuan. If he uses a brush, Wang Ji feels that he doesn’t have to take the exam, and he will be exhausted from polishing the ink~!

"Clang clang clang~!"

"Okay, time is up, Mr. Wang, please stop writing~!"

At four quarters after Shenshi, the academy’s gongs and drums sounded, and Li Zexuan immediately got up and said.

Wang Ji just finished writing the last word at this time, he let out a sigh of relief. He thought that an hour and a half was more than enough, but now he doesn't even have time to check, so he has to hand in the paper.

"Haha~! Wang Wugong, how did you get on the test?"

As soon as Wang Ji handed in the paper, Yan Silu asked immediately.

In that tone, I don't know whether it is gloating~IndoMTL.com~ or worrying.

"No more, no more! I'll talk about other things later, the old man has a headache now, and I have to go back and rest~! Shan Chang, Wen Ji, Kong Gui, let the old leave first~!"

Wang Ji wrinkled his eyebrows, squinted his head, stood up and said with a painful expression that he was a little over-exerted in this exam.

"Mr. Wang is unwell? Would you like a kid to call the doctor for you?"

Li Zexuan asked with a worried look. He didn't want to destroy Wang Ji, the "genius" because of an exam.

"No, the old man just feels a little tired. After a nap, it should be no problem~!"

Wang Ji waved his hand.

………………………

Second more!

The third one is very late, let's see it tomorrow morning!

(End of this chapter)