Chemistry problems for graduating classes, next year will be the graduating class, will chemistry be

The first sentence is fine, the solution is made up of solutes and solvents.

Yes, the main ingredient is salt.

Stratified, non-stratified, stratified, ethanol does not dissolve potassium permanganate.

Not necessarily. It is dilute hydrochloric acid, not concentrated hydrochloric acid.

Iodized salt is sodium iodide. Of course, it can dissolve in water.

1.There is no problem, the solution is all a mixture.

2.The iodized salt is potassium iodate, not iodine, otherwise the starch is not completely blue.

3.Stratification, non-stratification, stratification (in fact, ethanol has reducing properties and will react with potassium permanganate) proves that potassium permanganate solution cannot be dissolved in ethanol.

4.Not necessarily a dissolution reaction? Dissolution reaction? It's not called that.

5.This is related to activity and will be studied in high school later.

The reducibility is iron elemental "hydrogen" divalent iron.

Oxidation is ferric iron "hydrogen ions" divalent iron.

The reason why iron can react with acid to release hydrogen is actually a redox reaction.

Hydrogen ions are reducible, but they have limited ability to reduce iron to the form of ferric iron, and no matter how high they are, they have no ability.

And concentrated hydrochloric acid is the same, it is also bivalent iron.

If the sulfuric acid is concentrated, it will be passivated at room temperature, and the heating will produce ferric iron and sulfur dioxide.

Now you don't need to grasp so much, you just need to know that if the replacement reaction iron is bivalent, metathesis depends on the original valence, and the original price is the price.

1. The solution is a mixture, which is composed of at least two substances (solvent and solute) 2. Iodine refers to iodine element, which is insoluble in water, and iodized salt is the salt of iodine element, and it is soluble salt, which is soluble in water.

3. No stratification, and no stratification after **. This indicates that ethanol and water are miscible with each other.

4. No, (the process of one substance (solute) being evenly dispersed in another substance (solvent) to form a solution is called dissolution.) By definition, the dissolved solute and solvent are non-reactive.

5. This is because dilute hydrochloric acid has no strong oxidation and cannot directly oxidize iron to trivalent. (I'll learn this in high school).

Chemistry in the third year of junior high school is not difficult. But the beginning is important. Therefore, if the teacher asks you to memorize chemical symbols, you must memorize them carefully.

It's like learning pinyin in elementary school. After that, as long as you can listen carefully, there should be no problem. I remember saying this to our chemistry teacher when I was in junior high school.

And next year, when you go to high school, you will know that chemistry in the third year of junior high school is only a rarity in high school chemistry, and it will take less than a month to complete the review. Therefore, it is important to lay a good foundation when you are just starting out!

Learn not to ask why, not to get into the nitty-gritty.

For example, why P2O5 and not others, why Al2O3 can be called alumina and Fe3O4 must be called ferric oxide.

These will be solved quickly in the later study.

But if you don't let go.

It can make learning difficult.

The graduating class only learned chemistry, it can be seen that it is a junior high school student, rest assured, junior high school chemistry is not difficult, but the key is to lay a good foundation, remember what should be remembered, and have confidence in yourself.

Ou is about to enter the third year of junior high school The junior high school part of chemistry is very easy to learn, mainly by memorizing and cultivating interest in chemistry. I personally think that interest is very important, otherwise I will be bored after high school, if I am admitted to the university and have a chemistry major, then you will be nb, it is simply heaven. In there is that I don't think you need to study on your own, that little thing in junior high school, you don't know what the point is, or wait for the teacher to talk after the start of school, it's not difficult, as long as you don't desert!!

The most important thing is the chemical reaction phenomenon, the chemical formula, and the valency

Remember, you should be able to handle it later

The most important thing is to understand, to rely on one's own associative ability, to connect the micro with the macro, and to chemistry small kis

Hey... Chemistry in junior high school is too simple.

The line intersects the y-axis, and the c(zn2) mol l 1 of this point can be deduced from the logarithmic relationship, and the x-axis corresponds to the ph value.

In its negative semi-axis, the pH is less than, i.e., c(h+) 1 10 6 mol l 1 , and c(zn2 ) may be mol l 1

Brother, I was half wrong)

First of all, you should pay attention to the effective information in the question stem, and extract it, which will help you solve the problem below, and then carefully look at the flow chart, there will generally be solutions or precipitation and the like, try to push, especially in the solution, to mark out the ions in it, and then combine with the chemical basis, it is easy to solve. It should be added that sometimes the following questions may have hints.

How could there be?

Studying well and preparing is king.

good luck.