Chapter 133

Li Zhengcai realized that the passage had been finished.

So where is the point of laughter

"Ah Isn't it funny? " Shen Yiyun scratched his head with a simple smile, "this is probably the stem that only people in the chemical industry can understand."

"No, no, no, it's funny. If I knew what the dean and tutor were, I would have laughed."

"To acridine to acridine, the president is a real overtime maniac, elder martial brother is equivalent to looking for a person with 100 steps to report 50 steps."

"Ha ha ha I see. " Li Zheng forced a smile, and then said, "the stem itself is more difficult to get, but the elder sister is really interesting to talk about. You go to the play and absolutely look better than the present Huadan."

"Oh, dear..." Shen Yiyun's face turned red again Art comes from life ~ "

on the other side, Shi Yang pinches the dropper and seems to be pinching blood.

He listened to the same whisper of mosquitoes.

It doesn't feel right.

Isn't this an area that respects chemical strength?

Big sister of chemistry, don't be confused by this guy who looks like a scum man.

Look at me. Look at me.

However, Shen Yiyun and Li Zheng are chatting more and more hotly. They can't help but perform more hospital jokes and smile from time to time.

Shi Yang couldn't bear it. He just said in a deep voice, "then I started?"

Hearing this, Shen Yiyun's face was covered with frost.

"Well, please."

Shi Yangyi gritted his teeth.

What a change of face?

No, big sister.

I will save you with chemical strength!

As soon as Shi Yang was cruel, he didn't even look at the experimental principles and steps, so he began his performance.

"Preparation and titration of Coumarin-3-carboxylic acid, Shi Yang."

He said, unscrewing a dark reagent bottle (salicylaldehyde), pinching the burette into it, slightly absorbing, then picking up the measuring cylinder, dropping the solution into it, quickly repeated twice, then screwed on the reagent bottle, without looking at the scale of the measuring cylinder.

"Wait a minute. It's going to be deducted." Shen Yiyun raised his hand and sneered, "look at the roll face - take 2 ml salicylaldehyde, do you know how much you took?"

"2 ml." Shi Yang did not squint. He had already unscrewed the second reagent bottle (diethyl malonate),

SHEN Yiyun's nose was tight, and he wanted to check it immediately and kill him.

But as a research two big sister, really so haggard, always appears to lose face.

Although Li Zheng was very good at observing words and expressions, he was not strong enough to see this layer. He just walked around the test bench with curiosity instinct, lying on the table and staring at the scale.

2ml, exactly the same

There was a legend that there was a big sister who sold sugar. She called it "a catch", and she was forced to do so.

Today, he has witnessed the accuracy of cobalt God.

At this time, he turned to look at the man who had absorbed the reagent.

It's like the whole person has an invisible chemical molecular gas field.

This man, he's no longer Shiyang.

He's the God of cobalt.

At the same time -

[school movement was detected. 】

[Shi Yang: 27]

[learning limit: 26. 】

[learning 】

[academic movement + 0.1 】

【+0.1…… 】

Li ZHENG'ER was staring.

He doesn't close his eyes. He doesn't close his eyes before he sucks enough to learn sports.

At present, the only reference for the school movement is Li Zheng himself.

It's four.

But Shi Yang, a loser, is nearly seven times as lucky as himself.

His experimental talents are really the atmospheric transport needed by the times.

Mine, mine, all mine!

Of course, stealing Qi Yun or something is just a joke.

For scholars, this is learning, brainstorming and common improvement.

Since the system is clearly said to be learning, then the Qi of cobalt God will not be reduced.

At home and abroad, the country's air transport has increased out of thin air.

Li Zheng just keeps his eyes on Shi Yang and returns to Shen Yiyun's side.

"It's 2 ml, exactly the same..." Li Zheng said softly.

"Er..." Shen Yiyun said bitterly, "this It's not very difficult. There was a senior brother three years ago It's OK. "

Once Shi Yang started the experiment, it seemed that he couldn't hear the person talking to him. In a flash, he poured 2.4ml diethyl malonate and 10ml anhydrous ethanol into a 50ml round bottomed flask.

In the middle of this, naturally, there are many small skills and small movements.

For example, when adding anhydrous ethanol, cobalt God obviously slows down the speed of adding, and at the same time, rapidly rotates the flask and turns to pour in circles.Obviously, this is the intention of cobalt God.

But Li Zheng couldn't see through.

"Why..."

Before he could ask, Shen Yiyun replied, "when dropping reagents, it was inevitable that some of them would stick on the wall of the bottle. He did this in order to wash down the other raw materials on the wall of the bottle with anhydrous ethanol."

Li Zheng's "Oh" voice, this just realized.

It is impossible to write these small details on the test questions.

Only those who have done a lot of experiments will naturally form some habitual skills.

Now it's just beginning. There must be a lot of these tricks.

Cobalt God, let's show you how to learn.

On the opposite side, after the cobalt God has prepared the solution, put the flask on the oil bath pan bracket, fix it, and then use a high-precision plastic syringe to take some piperidine, put the needle into the bottle and inject it carefully, and the solution will turn yellow.

"Hum..." Shen Yiyun suddenly smiles, but soon stops.

What did she see?

Li Zheng didn't know.

I don't even know if I asked.

Well, I don't ask. I'll just pretend to understand.

"Hum."

However, the cobalt God did not pay attention to them at all. He took a tube of glacial acetic acid and hung it on the beaker motionlessly. It was fixed in the middle of the beaker for a long time before dropping it.

Different from the natural and unrestrained action before, these two drops are very careful, and they must be afraid to touch the bottle wall.

Chemical experiments are very strict with the dose requirements. Most of the time, only one drop, a little more or less, will affect the reaction rate and reaction volume, and even unexpected strange reactions will occur in serious cases, eventually leading to the failure of the experiment.

Take the preparation of coumarin for example, the final yield score is as high as 40.

The theoretical yield is 2.53 G.

But that's just theory, and it's not a molecule that's lost production.

In the environment of university laboratory, the limit of yield is about 90% of the theoretical yield under the condition of human manual operation.

Therefore, when scoring, the final yield as long as higher than 80%, that is, full score, 40 points.

70%, 35 points.

60%, 30 points.

And so on.

Looking at the cobalt God who skillfully placed the condenser tube, Shen Yiyun finally got serious: "this kind of problem, from the undergraduate standard, as long as the production rate reaches 70%, it is excellent."

"That's 1.78 grams..." Li Zheng muttered, "you can get full marks in the competition, and the production rate should be higher than 80%, that is 2 grams. "

"Almost impossible." Shen Yiyun shook his head very confidently. "It's not that it's impossible in theory, but it's impossible for people who do it for the first time. It's very good to reach 70%. If you have a week and do it dozens of times repeatedly, constantly fine tune the dose, time and temperature, and pursue the limit, you may still be able to work out some methods to improve production."

"Dose, time, temperature..." Li Zheng couldn't help saying, "isn't this alchemy..."

"It's not much." Shen Yiyun raised his glasses. "Chemical experiment, in essence, is to manipulate the molecular activities of the micro world and create the needed substances through the magic of bonds and rings."

"Well..." After hearing this, Li Zheng felt that he had finally touched the threshold of chemistry.

At this time, he looked at Shi Yang, who was concentrating and smiling.

Li Zheng seemed to see a creator of the micro world.

In fact, this is the pleasure of chemistry!

Damn it.

The hands are itching.

I really want to do the experiment.

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