A few questions for high school chemistry review, senior year review, please ask a few chemistry que

How to say that?

1 mole of any particle or substance, when its mass is measured in grams, is numerically related to the phase of that particle.

Equal to atomic mass or relative molecular mass.

Just remember: the relative molecular mass is equal to the molar mass of the substance!!

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Now to prepare CuSO4 solution 250ml, copper sulfate crystals containing crystalline water CuSO4 are required

How many g?, 5h2o?Why is the 5mol of water in the copper sulphate crystal not taken into account in the calculation?

What does it mean to not consider the 5mol of water in the copper sulfate crystal? Think about it! When calculating the mass of copper sulfate crystals, you need to calculate! It's 250g mol instead of 160g mol

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c=(What does 1000ml l in 1000ml l m mean, and when is it needed.)

Multiply by 1000? Does it have anything to do with ?

1000ml L is actually a unit conversion problem, which means: 1000ml = 1L

But I don't know why it flashed suddenly.,To analyze the specific problem specifically.。。。

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The solute in the solution of NH3 dissolved in water is calculated as NH3".

Because the number of NH3 is much more than NH3·H2O

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What should be the next steps?

Just look at the textbook for yourself.

Volumetric flasks can't be used for dilution, isn't the washing and volume setting process diluting?

The teacher said, "Child, don't be so fond of getting into the horns!"

I said, "Son, it's okay to drill a horn point, but you have to drill it properly!"

That is: many steps are for the sake of safety and accuracy, and the volumetric flask cannot be used to dilute, but cannot be used to dissolve! Here is a special case, concentrated sulfuric acid is liquid, adding water is dilution, in fact, it can be understood as dissolving concentrated sulfuric acid, so it can not be operated in a volumetric flask.

Of course, when you dilute to a certain extent, you can pour it in and add water to dilute it, and then you can... Shrewd.. Don't get into the nitty-gritty.

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A certain amount of liquid compound XY2 is burned exactly completely in a certain amount of oxygen, XY2 (L) + 3O2 (G).

XO2(g)+2YO2(g) The volume of the product measured after cooling is 672ml, and the density is .

It can be calculated that XO2 is generated, YO2 is generated, and why the oxygen that is reacted is is.

What about xy2? This is so annoying... Can you not answer???

Oops... Well, it's actually the conservation of oxygen atoms, and then what about xy2, because o has already appeared in the title, which means xy2 is oxygen at noon!

Note that x and y actually represent one element.

1.No, it must be converted into ferrous hydroxide ...... first

2.The turbidity is divided into emulsion and suspension. The suspension can be filtered, because it is a small solid particle, and the emulsion is not, and the liquid particles are inside, and the method of extraction and separation should be used

3.Tyndall and electrophoresis are indeed colloidal, and the concept of Brownian motion is that "the phenomenon of suspended particles moving irregularly without stopping is called Brownian motion", so it is not necessarily colloidal. The main reason for the stable existence of iron hydroxide colloids is that the colloids are positively charged and adsorb the anions in the water, and the anions repel each other, resulting in the inability of the colloids to aggregate, resulting in colloidal stability.

It has nothing to do with Brownian motion......And I think it's because of the colloids that they are so tightly connected that they collide and cause Brownian motion.

A: 1Can copper hydroxide be converted to iron hydroxide in one step? The latter has a small solubility and should be fine. And the answer is no, why?

Generally, no. But if the question gives the solubility product, and then ask whether it can be transformed, it is okay. (The premise is that the solubility product of Fe(OH)3 should be small).

2.The turbidity can be separated by filtration (the suspension can be separated in this way, and the emulsion will be divided).

Tyndall phenomenon, Brownian motion, and electrophoresis are all properties specific to colloids (Brownian motion is not unique to colloids, turbidity fluids also have Brownian motion).

The main reason for the stable existence of iron hydroxide colloids is the Brownian motion of the colloids (this is a secondary reason, the main reason is that the colloids are charged).

1. Of course not, don't forget, if copper hydroxide is to be converted into iron hydroxide, it will also be separated by ferrous hydroxide during the period. If I'm not mistaken, ferrous hydroxide is very unstable and easily converted to iron hydroxide, but don't forget its existence. 2. The turbidity is divided into emulsion (milk, etc.) and turbidity (adding soil to the water), the emulsion cannot be filtered, and the suspension can.

3. That's right, those three are the properties of colloids, but the properties of colloids are not the reason for the stable existence of colloids, they are used to judge whether a solution is used for colloids, and the reason for the stable existence of colloids is the interaction between colloidal particles.

1. It is converted into ferrous hydroxide first.

2. Emulsion is not good.

Brownian motion is not a property of colloids, turbidity fluids also have Brownian motion, and if the colloids are not charged, they will not be electrophoresis.

The iron hydroxide particles are charged and repel each other, resulting in the inability of the rubber particles to aggregate, resulting in colloidal stability.

1. Middle school chemistry is written to have a reaction of gas, precipitation or water to react, which does not mean that a precipitate with a slightly higher solubility can be reacted into a precipitate with a slightly lower solubility, and a reaction with copper hydroxide will definitely react into a dissolved matter.

2. The turbidity can be divided into suspension and emulsion, and the suspension can be separated by filtration, but the emulsion cannot be separated by filtration.

Brownian motion is not colloidal-specific, it is written in the book.

Because they all have the same kind of charge, the colloidal particles are mutually repellent and are not easy to aggregate into large particles.

As soon as you know, why bother.

1.Both are microsoluble substances and cannot be separated.

2.(1) Please read the book about the properties of turbidity;

2) Brownian motion is ubiquitous and not colloidal.

3) The stability of ferric chloride colloids is because the main reason for the stable existence of ferric hydroxide colloids is that the colloids are charged (positively charged) and adsorb the ions (anions) in the water, and the anions repel each other, resulting in the inability of the colloids to aggregate, resulting in colloidal stability.

One question, it can only be converted into ferrous hydroxide first.

In the second question, filtration can only be used to separate the precipitate from the solution.

Brownian motion is not a property.

The main reason for the stable existence of iron hydroxide colloids is that the colloids are charged (positively charged) and adsorb ions (anions) in the water, and the anions repel each other, resulting in the inability of the colloids to aggregate, resulting in colloidal stability.

1.The two are not of the same type. A small solubility is not equal to reaching its precipitation equilibrium constant of 2

Take care to distinguish the properties of the emulsion from the suspension; Non-endemic; There are two reasons for the stability of colloids: First, colloidal particles can be charged by adsorption, and the same kind of colloidal particles have the same kind of charge, and the same kind of charges will repel each other.

1.Didn't understand ......

2.(1) Emulsion is not allowed.

2) Brownian motion is the commonality of all liquid substances, dispersion systems (solutions, polymer solutions, sols), and even liquids, and the essence is the irregular motion of liquid molecules.

3) The reason for the stability of the colloid is the force at the interface between the colloidal particles and the water (which can be seen as the surface tension).

1. The transformation of insoluble substances should not only look at the solubility, but also compare the solubility product.

2. The turbidity is divided into suspension and emulsion, the suspension is separated by filtration, and the emulsion is separated by separating.

Brownian motion is not a property specific to colloids.

The reason for the stable existence of colloids is that the colloids have the same electrical properties.

1. It may be due to the different pH required for precipitation.

2. Filtration is only used for solution ......Let's ......

Brownian motion is a phenomenon that is common to all gaseous liquids.

The main reason for the stable existence of ferric hydroxide colloids is inter-charge repulsion.

2. To add that not all colloids can be electrophoresised, and neutral colloids cannot [such as starch.

Gas washing cylinders generally have the following functions:

1. Washing gas 2. Collecting gas (divided into up, down, and draining method) 3. Observing the gas flow rate (see bubble velocity).

Long in and short out: gas washing, upward air exhaust method, observation of gas flow rate; Washing gas and observing the gas flow rate require the gas to be in full contact with the liquid in the bottle, so it should be long in and short out; The upward exhaust method requires air to go out from above, so it also needs to be long in and short out.

The safety bottle of anti-sucking only plays the role of holding the liquid when the sucking occurs to prevent the liquid from entering the reaction vessel, so the requirements for this are not high, but it is best to have both short or short inlet and long out (to avoid the incoming liquid does not pass through the catheter orifice and sucks again).

The principle of sucking is caused by the difference between the gas pressure inside and outside the device (when the external air pressure is the internal air pressure, the air pressure presses the liquid into the device, which is suction) If the end of the catheter is just flush with the liquid level, see if the liquid has not passed the catheter orifice, if it has not passed the catheter orifice, the air pressure difference can be generated.

Take, for example, children's shoes.

In the process of gas drying (or impurity removal), if a solution is used, then it needs to be long in and short out; If it is short in and long out, it will press the liquid over or gasp. The role of the safety bottle can indeed play a certain degree of sucking, but it cannot fundamentally solve the problem, so don't be mistaken about whether it is a long in and short out, or a short in and long out.

There is no principle for suction, only the reason, which is caused by the unequal pressure on the two sides. There are no specific examples and no explanations. If the end of the catheter is just flush with the liquid level, there is a possibility of sucking or not, and this specific problem is analyzed on a case-by-case basis.

First of all, in the first stage (memorizing concepts), what you have to do is to master the most basic conceptual knowledge, memorize chemical equations, summarize the equations that are often used in each exam, including balancing, and remember to be ripe, so that you can win a little time to do other questions in the college entrance examination (the college entrance examination is time-consuming, and it is difficult to complete all the questions, so there is no need to waste time calculating the balancing in the examination room for such instinctive notes).

The second stage (doing exercises) is to do a certain number of different types of questions, prepare a correction book, and sort out the mistakes during this period in this book (the book should be thicker, and you should have a sense of achievement, hehe), don't be afraid to make mistakes, you must know that during this period, it is a good thing to be able to make mistakes, at least you can find your own problems and correct them in time.

Finally (review),In this final sprint stage,You don't need to do so many questions.,Just take out your thick correction book and flip it over.,The questions that have been done can be put aside.,It's not very good to prepare a book again.,Find the more raw questions from the correction book.,Practice repeatedly,Oh,That's right,It's best to classify the papers of each big and small exam together.,After reading the wrong book, you can attack the above questions.,A few days before the exam, Then do a few more finale questions (must do), oh, at this stage, you have to do a set of questions every few days, familiarize yourself with the types of questions, and master the answering skills.

That's probably it, by the way, in the examination room, you have to know how to give up, first do the subjects that you have learned well, pick the questions that can be scored in order, and finally study those "additional questions".

Biology is the simplest of science, and the questions on biology are all conceptual things, so I suggest you buy a pass, the concepts on it are relatively detailed, or you can also use them to memorize if you have previous class notes, in short, conceptual things to memorize, and then pick up the common short-answer questions to the correction book and look through it, and the biology level can be completely passed.

I just took the college entrance examination this year, I hope these things are of some use to you, I wish you the title of the gold list!

The first round reviews the basics, the second round can consider doing some difficult problems, and the last round recommends returning to books, and most of the college entrance examination is still in books. I'm supposed to be a master of biology, but there's no special method, and there's a notebook that goes into great detail. You can try to do more questions, and if you do more, you will remember it, and it is easy to forget it by hard memorization, and what you memorize may not necessarily be used.

Do easy questions and medium difficulty questions, you don't have to do too many difficult problems, but you should be able to categorize, which can improve efficiency.

First, refine and condense the basic knowledge, shorten the content of the textbook to a form that is easier for you to remember, and understand the specific meaning of each part of the content against the exercises.

Second, do enough practice questions to filter out all the details of what you have learned and how to solve them. First do the more basic practice questions to directly reflect the learning content, and after there is basically no problem, do some more difficult exercises, and it is best to see the mechanism of the question.

The third step is to go back and sort out the basic content condensed earlier, and make more detailed supplements and annotations, and focus on the parts that were unclear and easy to make mistakes in the past to correct the mistakes.

If you can forget all those materials as well as you have ever seen a movie, you can go to the exam! Congratulations!