Get a chemistry expert to do you a favor 100

Recommend a teacher's book to you, I think back then, brother, I just read this teacher's book and did the questions on that book. The chemistry score is called a backgammon.

Send me a text message and I'll tell you which teacher it is.

And middle school chemistry, the teacher said**You learn**, don't go back and make up for the front, if you don't have that time, wait for the review and then follow the teacher's footsteps, the safest.

What grade are you in now?

If it's the third year of junior high school, buy a system review book right away, make up it from scratch, it should be in time, I made it up later, and I did well in the exam, so I must find a book with full content!

I'm from Shanghai.

First of all, you should cultivate your interest, if you don't like it, then you don't have to work hard, you should feel that you can learn it well, then you can learn it well" If you want to take 1 chemistry in the science subject of the college entrance examination, you must have a high score. Chemistry as long as the concept is memorized, the method is mastered, the typical example problems are done, and everything is OK >>>

Starting from the chemical elements, the law of acid-base firefly reactions, the sequence of metal activities, and then the equations, do your homework carefully.

My teacher said that when you master the basics of chemistry, you often understand it when you listen to it, but when you do it, your mind is blank"Tricks", just open up the second pulse of Ren Du.

Chemistry is simple, as long as you understand the class and then review it, but you haven't listened to the lecture before, then find a good friend in chemistry and make up for it for a long time, starting from the simple one.

Dizzy, how do I think chemistry is the easiest of all? If you want to take 1 chemistry in the science department of the college entrance examination, you must have a high score. Chemistry as long as the concept is memorized, the method is mastered, the typical example problems are done, and everything is OK >>>

I'm from Shanghai, I'm in college, I still chose chemistry in high school, and I made up for the chemistry of my younger siblings and neighbors, so look for me.

If you spend your QQ time studying chemistry, you will learn something.

409637970 Look at it, I'm from Qingdao."

My dad teaches junior high school chemistry and want to ask him for help?

Contact me if you want to – send me a message).

553018430 No, oxide glass is divided into silicate glass, borate glass, phosphate glass, etc. Silicate glass refers to glass with the basic composition of SiO2.

It is not possible to react without strong acid to make weak acid.

By calcium hydroxide solution.

Buy this resource book and take a look.

These are the basic questions.

Categorize it several times when understanding.

A systematic summary.

None of the above questions are a problem.

Everything in the world is made up of various elements. Please select the appropriate elemental composition of oxygen, carbon, hydrogen, and calcium, and write a chemical formula that meets the following requirements (only one for each element).

Metal oxides (CAO), acids (H2CO3), bases (Ca(OH)2), salts (Ca(OH)2CAC3), organic disinfectants (CH3CH2OH).

A chemical equation for the neutralization reaction is written using the above substance: (H2CO3+Ca(OH)2 =CaCO3+2H2O).

Calcium oxide cao

CH3COOH acetate

Calcium hydroxide Ca(OH)2

Calcium carbonate caCO3

Ethanol (alcohol) C2H5OH

2ch3cooh+ca(oh)2====ca(ch3cooh)2+2h2o

There are many kinds of acids, mainly organic acids, but the easiest thing to think of is carbonic acid, but in the general equation, carbonic acid is not written directly, but carbon dioxide and water.

cao ch3cooh ca(oh)2 caco3 c2h5oh

2ch3cooh+ca(oh)2==(ch3coo)2ca+2h2o The calcium acetate upstairs is slightly problematic The acetate should be written in front of it is more conventional.

It's very simple, the key is to understand the definition of each substance.

Calcium oxide, carbonic acid, calcium hydroxide, calcium carbonate, ethanol, the chemical formula can be written.

h2co3+ca(oh)2 =caco3+2h2o

I can't do anything else, but I'm very good at chemistry. Now that I'm in my third year of high school, many people ask me how to study chemistry when they ask me about chemistry. But as far as my limb experience is concerned, learning chemistry, especially memorizing equations, must get to the bottom of it!

Chemical systems are like a spider's web, and there are many connections between them. Most people have a headache and think that there are already a lot of knowledge points, and there are so many connections, wouldn't it be more troublesome!In fact, this kind of connection is a shortcut to facilitate memory.

Every time I learn a new aspect, I often connect with what I have learned before, and then I only need to memorize a few new knowledge points to master it. The most recent tests have all scored above 95 points. If you want to make up for it, it's not impossible.

But don't be greedy for questions, you must get to the bottom of the question, do this question, dozens of questions!For example, the learned δg = δh-tδs, the more chaotic, the greater the δs, so we know why SiO2 can react with CaCO3 at high temperature to form CO2 and Casio3, because the entropy of the gas is large, the chaos is large, we can also know why ethyl bromide reacts with sodium hydroxide, in water, it is ethanol, in ethanol, it is ethylene. It's like similar to each other, but the polarity of the ethanol molecule is too low.

Why benzene reacts with bromine, iron bromide should be used as a catalyst, because iron has bivalent and trivoidal valence, and can have iron bromide and ferrous bromide, so iron atoms can control the input and output of a single bromine atom, we all know that atomic reactions are easy to molecules. It can also be related to why catalysts generally like to look for transition elements, because there are many valence states of transition elements! In your own work, think about how much knowledge you have not digested.

In order to avoid always not knowing how to do the question, knowing the answer only to suddenly realize, and then feel that I am not working hard enough, the IQ is not high, how can the person who asked the question be so smart! I'm sure you'll be able to gradually find confidence in doing the questions, and in the exam, despise the chemistry questions!

In Question 1, Part 1, copper does not react with dilute sulfuric acid, and the remaining insoluble matter is the copper in the original mixture.

i.e. m(cu, mixed) =

In the second part, the copper does not react with the copper sulfate, and the Fe is all dissolved and replaced with the copper in the copper sulfate.

The insoluble substance is copper, but it is divided into two parts: one is copper in the original mixture, and the other is in copper sulfate.

There is the copper that was replaced.

m(cu, total) = m(cu, mixed) + m(cu, generated) =

Therefore m(cu, generated) =

At this time, Fe has the following relationship with copper sulfate, let the Fe mass in the mixture be W, yes.

fe+cuso4===cu+feso4

w so w = the percentage of cu in the mixture is (one part is the same as half of the mixture).

cu% = Question 2:

1) The amount of hydrochloric acid is sufficient, and the mass of H2 produced by the three metals is X, Y, and Z respectively, so there is the following relationship.

mg---h2 zn---h2 fe---h2

30g x 30g y 30g z

It is obtained by the proportional relationship.

x= y= z=

2) The amount of hydrochloric acid is sufficient, and the masses of each of the three metals are A, B, and C respectively, so there is the following relationship.

mg---h2 zn---h2 fe---h2

a 30g b 30g c 30g

The relationship between the Khan and the Khan can be solved.

a=360g b=975g z=840g

I've written as much detail as possible.,It took a lot of time.,The landlord gave you a good review.,It's not in vain that I'm working so hard.,Hehe.。

One part adds a sufficient amount of dilute sulfuric acid, and after the reflection is completed, there is an insoluble substance, indicating that the copper in it is another part of the solution with a sufficient amount of copper sulfate, and finally the insoluble matter is obtained, which contains the original copper and the copper replaced by iron Replaced by copper =

Since iron and copper are one for one, iron is.

So the same mass fraction is.

mg---h2 mg---h224 2 24 230 x y 3024x=2*30 24*30=2*yx= y=360g

The same goes for the other two.

1.Analyse.

A sufficient amount of dilute sulfuric acid is added to one serving, and after the reflection is completed, there is an insoluble substance "It can be known that the insoluble matter is copper, that is, there is copper in one part, then there are 13 grams of copper in the original mixture;

The other part adds a sufficient amount of copper sulfate solution, and the final insoluble matter can be known to produce the quality of the copper is:, Fe+CuSo4==FeSo4+Cu

56---64x=

If there is iron in one serving, there is total iron in the original mixture.

The mass fraction of copper in the original mixture is: 13g (13g+2.).Solution: If each of the three metals is 30 grams, the mass of hydrogen produced is X, Y, Zmg+2HCl==MgCl2+H2

30g---x

x=zn+2hcl==zncl2+h2

30g---y

y=fe+2hcl==fecl2+h2

30g---z

z=mg+2hcl==mgcl2+h2

x---30g

x=360g

zn+2hcl==zncl2+h2

y---30g

y=975g

fe+2hcl==fecl2+h2

z---30g

z=840g

1.The answer is.

The insoluble substance of the first part is copper, and the mass is, that is, the mass of the copper in the mixture, and the insoluble substance of the second part is also copper, and the mass is, why would the second part be more than the first? That's because the second part has a displacement reaction, and the iron replaces copper, so the more is the mass of the replaced copper, that is, the amount of iron substance, so the mass of iron is.

zn--h2, fe--h2, do your own calculations, practice more.

A few days ago, I gave other students a method and introduced it to you, (with changes) for your reference.

First of all, adjust your mindset. This is critical. To adjust your mentality, at least, for the sake of your goal, you have to work with it"Rapport".

If you are already planning to learn it well, I will introduce you a little bit of my experience in learning and teaching, but you must have patience and perseverance to endure hardships.

1. Now, take the time to read the chemistry textbook and notes, and mark the knowledge that you don't think you remember, so that you can easily focus on it in the future;

2. Do a good job of the teacher's unified review materials, not wait for the teacher to speak, so the effect is not good, after class, you should not understand the questions and do not understand the questions, use notes, textbooks and other materials or ask others to sort out, it is best to organize in the notebook, and more strengthening; If you feel that you have spare energy, you can carefully select a suitable material for yourself to improve and improve;

3. There are many comprehensive review exams, and when the teacher analyzes the test papers, he should not only listen attentively, but also sort out the difficult points, sort out every knowledge point that he does not understand, so as to check and fill in the gaps, improve in an all-round way, and persist until the college entrance examination, even during the college entrance examination.

4. Especially in chemistry and biology, don't underestimate the textbooks and original notes. From the second semester of the third year of high school to the college entrance examination, you should read the textbook at least three times, the first time, read carefully, read the content of the selected school, and mark the places that you feel are confused and have not remembered; After the second pass, you have to focus on it, and read it all anyway on the last time.

Stick to it, the success or failure of the comprehensive depends on whether chemistry is good or not!

What a way to help You have to be interested and confident in everything you learn.

1.Because they are all divalent metals, the product bit XSO4 is obtained, so you can think of 40 grams of metal mixture as a metal X, and then finally get 136 grams of XSO4 136 grams, 136-40 = 96 grams = 1mol of SO4 weight, so you can know that there is 1mol of H2SO4 to participate in the reaction, so H2 1mol is released, which is 2 grams.

The element is 2 8 6 structure S, the Z element is 2 6 structure O, sulfate, sulfite, and the X element is +1 valence element, so C is chosen

10 xx=20/24

10 grams of pure magnesium can theoretically produce 5 6 grams of hydrogen, and there are still 2 grams of hydrogen, either there is a non-weighting substance in it (such as sodium, molar mass 23 is smaller than magnesium, and many more, this is just one example) or increase the production of hydrogen, such as aluminum.

2al+3h2so4==al2(SO4)3+3h2 They are 2:3 reactions, so only D can be chosen