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Anonymous users2024-02-071. The right way to learn.
Although chemistry is a science course, there are still many things that need to be memorized, so when high school students learn chemistry, they should not rely on all the problems, but also take time to memorize.
For students with poor grades, the learning method is the most important, can you seriously follow your own plan to improve yourself step by step, to improve your grades in various subjects, I have studied in Gaotu High School before, I have made a study plan, you can go to Gaotu High School to find out, the execution can only rely on the mutual supervision of classmates' parents.
2. Good study habits.
Not only chemistry, but also other subjects in high school should also have good study habits. Before class, take a look at what the teacher is going to talk about and try to understand it, that is, do a good job of pre-class; Prepare everything you want to use before class, take down everything you don't use, tidy up the desktop, find things conveniently without wasting time, and there will be nothing else on the desktop to attract your attention.
3. Listen carefully in class.
Most of the students who did not do well in high school chemistry did not listen carefully in class, and they couldn't learn it after class, and then they didn't do it. You must know that the most learning time every day is in class, and learning can only be understood by the teacher's explanation, if the class efficiency is not high, it will be difficult to improve the chemistry score.
4. Wrong question book.
Sorting out the wrong questions is a process of self-improvement, tidying up the mistakes made in the learning process, and then looking at their own mistakes, correcting them, and trying not to make a second mistake, so that the small problems in learning have been corrected, and the learning efficiency has been greatly improved.
However, high school students are pressed for time, and it will be a waste of time to sort out each question, so it is recommended to sort out the common mistakes and key questions. Mark the other questions and make time to review. False Swift Scramble.
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Anonymous users2024-02-06It is necessary to memorize more reactions, memorize familiar with them, do more problems, and memorize models.
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Anonymous users2024-02-05n(h)=2n(h2o)=
The rest is o.
C: H: O=1:2:1 can be obtained
So the simplest (experimental): CH2O
m（x)=60
The molecular formula is C2H4O2
2.(1) CH2-Co-CoCH3 (2) CH3CH2COOH CH3CO-CH2OH and HCoOC2CH3 (there are three types).
3.There are 3 kinds, and I'm posting a picture.
Analysis: salting out generally refers to the process of adding inorganic salts to the solution to reduce the solubility of a substance and precipitate.
After the addition of sodium chloride, the solution has a certain amount of Na+, which reduces the solubility of sodium of higher fatty acids, while glycerol and water are misluble in any ratio and are not affected by it, so they are separated.
I wish the landlord a better level!
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Anonymous users2024-02-04This is how the first question should be solved.
Suppose this substance is a (the middle unit is omitted, it is difficult to write) n(c)=
n(h)=2*(
n(a)=n(c) n(a)=2 n(a) n(h)=4, so the molecular formula is preliminarily c2H4O?
A molecular weight 60 = 12 * 2 + 4 * 1 + 16 *?
Therefore, the molecular formula is C2H4O2
2 Ibid. 3 I won't send a picture, just look at the above!
4a a: water ethanol miscible water and other immiscible water are lighter than carbon tetrachloride; Water is heavier than hexane (colorless transparent liquid, volatile. Specific gravity, soluble in alcohols, ketones and ethers, insoluble in water. ）
B: Glycerol is soluble in water and cannot be separated.
C: CaCO3 precipitate was generated.
D: The narrative is inaccurate.
Chemistry is more memorized than Chinese and English, and it is not good to learn chemistry if you don't spend some time memorizing. If you can't learn chemistry well, you can only say that you don't memorize enough.
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Anonymous users2024-02-032na+2h2o=2naoh+h2↑
is sodium, which produces hydrogen, according to the molar volume of the gas.
If the reaction is generated, then c=nv=
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Anonymous users2024-02-02Solution: n(Na)=,N(NaOH)=n(Na)= then the solution after the reflection: C(NaOH)=
n(h2)=from 2na h2
i.e. v(h2)=n(h2)*vm=
The equation in your book must be like this: 2h2(g) +o2(g) = 2h2o(l), right? >>>More
There are two main factors that affect the radius: one is the number of electrons outside the nucleus (generally speaking, the more electrons there are, the farther away from the nucleus, the larger the radius). >>>More
In this reaction, there is only the electron gain and loss of nitrogen element, the valency has risen and decreased, so C is wrong, the increase of nitrogen in metadimethylhydrazine is oxidized, it is a reducing agent, so a is wrong, the reaction is the recombination of atoms, so there is an endothermic and exothermic process, C is wrong, D is left, of course, there are eight electrons transferred from two N2O4 to N2 D is correct.
It doesn't seem to be a contradiction. The structure of the electron layer is the same, which means that it is the same three-layer and the same four-layer ......For example, Na and Cl, the radius of Cl is much smaller. >>>More
Organic substitution can also be understood as replacement.