I love chemistry!! But, help!! Chemistry

If I'm not mistaken, when you speak actively, you may make something that goes beyond the content of the textbook or beyond the requirements of the curriculum standard (if you are in junior high school, then your speech may involve high school or even college knowledge), so that the teacher will think that you are too messy. In fact, it is good to read more extracurricular books, but I have a unique insight that I suggest you communicate with the teacher after class, because if you ask it in class, the teacher can't know what you're talking about, but the teacher can't explain it for you alone in class, because other students don't know! Besides, you have extracurricular skills, but don't often use them in the test papers, if you exceed the requirements of the course standards, it is a mistake!

Therefore, it is recommended that you keep quiet and consider the feelings of teachers and classmates when using the knowledge correctly, so that the problem will be solved?

I am also a chemistry major in high school and hope my advice will be helpful to you.

Hehe, you ask your class what the people think is the best, ask a few more people, see if your opinion is objective or just your own bias, maybe a little bit is definitely not the teacher who is jealous of you and excludes you, either I don't like your too flamboyant style, or I just want to leave some opportunities for other students to learn to speak!

What are you doing with him, my table mate is the kind of person who is naïve and knows a lot of chemistry knowledge, he doesn't raise his hand and shouts out, the teacher is not in a rut, you just answer the call in class, don't care if the teacher calls you or not, but are you sure that you are not excluded because of your bad performance, the teacher should not hate students who love to learn.

I've had this question before. Maybe the teacher will take care of the whole class, since you know how the teacher won't call you, or the teacher has his own good intentions, so you don't get too flustered. Maybe you read some extracurricular books and understand some extracurricular knowledge, and you use it at the time, but there is no requirement for this lesson standard, which will make some students dizzy, and the teacher does not want to waste time to talk about it.

So you'd better not use some extracurricular questions in the future just to go to the teacher.

You're not telling the truth

How can there be such a chemistry teacher

I suggest you change schools

Or you take the initiative to talk to your teacher, maybe he expects something else from you, don't think of the teacher as you say, and your relationship will get worse and worse, and it's not good for you, it's not good for the teacher

Oh, hello landlord, I also like chemistry the most!

It's good that you like chemistry and you have an interest in learning. If you are willing to drill chemistry, the results will definitely be good.

The teacher excludes you, don't care. You have to learn chemistry better and get high scores in exams to prove your ability! Give the teacher a powerful riposte! See he's still squeezing you out... Work hard to learn well, as long as you have real skills in your hands, you are not afraid of anything!

Happy New Year's Day and academic progress!

Ignore him, the more he excludes you, the more you have to show him.

Your teacher is too jealous, just leave him alone and do what you think you want to do.

Go your own way and let others say go!

Don't pay attention to the teacher, do whatever you like in chemistry class.

To sum up, the ions that must be contained in sewage are Ba2+, the ions that OH- definitely do not have are SO4 2-, and the ions that cannot be determined by CO3 2- are K+, Cl-

Take a little sewage, drip into dilute H2SO4 to produce a large amount of white precipitate, and then add dilute Hno3 precipitation, which does not disappear.

This sentence indicates that there must be Ba2+, because H2SO4 and Ba2+ produce BaSo4 white precipitate.

Since there is Ba2+, there must be no SO4 2- and CO3 2-, because both SO4 2- and CO3 2- will precipitate with Ba2+, so that no colorless and transparent solution will be obtained.

Tested with pH test strips, the test strips are dark blue.

This sentence indicates alkaline, so there must be oh-

k+ and cl- cannot be judged.

ba2+、oh-

co32-、so42-

k+，cl-。

Colorless and transparent, indicating that Ba2+ CO32-SO42- can not coexist, adding H2SO4 to produce a large amount of white precipitate, and then adding dilute HNO3 precipitate, does not disappear, indicating that this precipitate is BaSO4, so there must be Ba2+, so there can be no CO32-, SO42-.

Tested with pH test strips, the test strips are dark blue.

It means that the solution is strongly alkaline, so there must be oh-.

1. Colorless and transparent, then it is necessary to exclude the ions that will precipitate each other in the possible examples mentioned above.

For example, Ba2+ and CO3 2-, SO4 2-

2. If the white precipitate insoluble in nitric acid occurs with the addition of sulfuric acid, it is determined that there are Ba2+ ions, then SO4 2- and CO3 2- must not exist.

3. The pH test paper is blue, and the solution is alkaline. The ions that can be alkaline on it are no longer CO3 2-, so there is only OH-.

So there is definitely ba2+, oh-

Definitely not CO3 2-, SO4 2-

Indeterminate: k+, cl-

The ion that Ba2+ H+ OH- definitely does not have is CO32- SO42- The ion that cannot be determined is K+ Cl+

There is definitely ba2+, oh-

Definitely not. Cl-, K+ cannot be determined

Because there is precipitation in the dropping of sulfuric acid, and nitric acid does not disappear, there is Ba2+, the sewage is colorless and transparent, and there is Ba2+, so there is no SO4 2-, CO3 2-, PH test strip test dark blue, alkaline, so yes, K+ can not be determined.

CO32- ions are pale blue and therefore do not contain, while Ba2+ and SO42- cannot coexist through. Get, contains Ba2+, no SO42-Indicates that the liquid is an alkaline solution, so it contains oh-, while.

k+ cl- is not possible to determine whether it is contained or not.

is a compound, but the NaCl solution is a mixture because the solution is a solute plus a solvent.

2.Many organic substances can be used as solvents, such as ethanol, propylene glycol, ether, petroleum ether, xylene, kerosene, gasoline, ......

3.Reactive metals are easy to react with oxygen to form oxides, in which metals lose electrons and form cations, so the active metal oxides produced are naturally ionic compounds, and then belong to electrolytes. The first floor says that "all metal oxides are non-electrolytes, and metal oxides can only conduct electricity if they are dissolved in water to produce the corresponding alkali, and they themselves do not conduct electricity."

This is not true, because the electrolyte is not necessarily dissolved in water ionization, and the substance that conducts electricity in the molten state is also an electrolyte. In addition, in the high range, only H2O is a weak electrolyte in non-metallic oxides, and the other non-metallic oxides are non-electrolytes

4.Organic substances such as sucrose, alcohol, and glucose are not mixtures, they are non-electrolytes5As for the method of setting 1, I can't explain it clearly, so let's see the reference materials for details.

1. The solution includes solutes and solutions, so it is a mixture, such as alcohol, gasoline!

Could you please double-check the equation? I don't remember having Cu2P, well, that's okay, but there's a couple of places where there is sulfuric acid on both sides of the equation, which is inappropriate, and the molecular formula for white phosphorus is p4, which affects whether to choose a or b, and the trim coefficient is 11 15 24 5 6 15, but the faster way to do this is to calculate it based on the conservation of electron gains and losses.

I've also referred to a few other similar issues.

You can definitely see it.

The concentration of ammonium iron alum standard solution is 25 mg l.

Get the formula: a = - c =

The sample is diluted 50 2 = 25 times in total.

The iron content in the sample is 25*

It can only give you an idea, and the calculation is too complicated.

1. Calculate the concentration of the standard Fe3+ solution first

2. Linear regression: determine the functional relationship between the iron standard solution and absorbance a=f(v)3. Substituting the measured absorbance into the linear regression equation to obtain the concentration of Fe This is a typical colorimetric method, involving the content of the linear regression equation. The chemistry college entrance examination is definitely not examined.

Calculate Fe content by insertion method:

Wait for the name to be solved.,Hey.,It's a pity that I don't even know the absorbance of chemistry in high school now.。