Conservation of chemistry in high school 1, three conservation laws of high school chemistry

Conservation is the most basic thing that high school chemistry should master, and it is very useful.

Conservation of mass means that the sum of the masses of each substance before and after a chemical reaction does not change.

Conservation of elements means that the types of elements that make up the substance before and after participating in the chemical reaction remain unchanged, and the number of atoms does not change.

Conservation of electrons means that in the redox reaction, the total number of electrons obtained by the oxidant is equal to the total number of electrons lost by the reducing agent.

Conservation of valency refers to the equality of the absolute values of positive and negative valency in a compound or mixture.

The first three of them are more important, when you write a chemical formula, you can test it by different methods, for example, you can use the chemical formula written by the conservation of elements, you can use the electron conservation test, try to use different methods, reduce the possibility of error.

There are still many rules to follow in high school chemistry, the basic ones must be memorized, and the ones that should be memorized must be memorized, and it will be much easier to do the questions. Special reactions should be familiar, and memorization is also a good way to write chemical formulas. You can also buy a little more reference books, read the easiest way to read the reference books, and then understand and remember, in this way, you will save a lot of time when you do the questions, you must figure out the essence and principle, otherwise some things will not work by rote.

Chemical conservation is divided into conservation of mass and conservation of charge.

Conservation of mass means that you write the same number of atoms on both sides of the reaction equation.

e.g. 2 H2 + O2 = 2 H2O; h four on the left and two on the left and two on the left and right.

Conservation of charge is the algebraic sum of the two sides of the reaction equation you wrote.

For example, 2 H+ +CO2 2- = H2O + CO2 left = 2+(-2)=0

Right = 0 = Left side.

There are a lot of problems that can be solved with these two.

A lot. 1 Conservation of charge: such as the ionic reaction formula of sodium hydroxide and aluminum hydroxide:

OH- +Al(OH)3 = ALO2- +2H2O (the total number of charges on the left and right sides of the chemical formula is the same).

2. Conservation of materials:

Na2CO3 solution: Na+=2CO3- +2HCO3- +2H2CO3

That is, the atom is conserved, and the amount of Na is equal to twice the number of ions containing C.

3 The number and type of atoms on the left and right sides of the chemical formula are the same, that is, the atoms are conserved.

It's very unsystematic, you have to read the information book.

It is necessary to memorize a few chemical formulas appropriately, but once you know the principle, you can write down many of them even if you have not seen them.

There is the law of conservation of mass, and there is conservation of charge, and there is conservation of proton number.

It is recommended to use a knowledge map, so that you can grasp the knowledge points. There are many chemical conservations, and the basic mass is conserved, which is commonly used in junior high school. The most commonly used in high school is the conservation of charge and the conservation of the number of atoms before and after trimming.

The writing of the chemical formula should pay attention to the algebraic sum of the valency of the elements in the compound as zero. This requires you to remember the regular valencies of common elements. This is how it is easy to write, and it is recommended that you memorize it with a mantra:

Monovalent potassium hydrochloride, sodium silver, divalent barium oxygen, calcium, magnesium, zinc, trialuminum, tetrasilicon, pentanitrogen, phosphorus, ditriiron, 244 carbon, 246 sulfur are complete, 2467 manganese mind, copper and mercury bivalent is the most common, and the elemental valence is zero.

There are three conservation laws in high school chemistry: conservation of protons, conservation of charge, and conservation of materials.

Proton conservation means that the number of protons lost by the acid is the same as the number of protons gained by the base.

Conservation of charge: 1. The algebraic sum of the positive and negative valency of the elements in the compound is zero.

2. The total number of positive charges carried by all cations in the solution is equal to the total number of negative charges carried by all anions.

Conservation of materials: 1. Conservation of particles containing specific elements.

2. The specific particles formed between different elements are conserved in the ratio of birot.

3. The relationship between specific particles is conserved.

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The three major conservations are as follows:

1. Conservation of electric charge.

That is, the solution is always electrically neutral, so the total positive charge of the cation band is the total negative charge of the anion band.

2. Conservation of materials:

That is, the specific proportional relationship between some elements present in the composition of the added solute, since there must be H and O elements of water in the aqueous solution, the equation in the conservation of materials must be the relationship of non-H and O elements.

3. Conservation of protons.

That is, the conservation of H+, the total loss of H+ in the solution is equal to the total number of H+, or the total amount of H+ ionized by water in the aqueous solution is always equal to the total amount of Oh- ionized by water.

Introduction:

Chemistry is a kind of natural science, mainly at the molecular and atomic levels, studying the composition, properties, structure and change laws of matter, and creating new substances (the essence is molecules that do not exist in nature). The world is made up of matter, and there are two main forms of change: chemical change and physical change (there are also nuclear reactions).

Take a look at it first, ask me if you don't know!

1. Conservation of charge: In the electrolyte solution, no matter how many ions exist, the solution is always electrically neutral, that is, the total number of negative charges carried by anions must be equal to the total number of positive charges carried by cations, which is the so-called law of conservation of charge, such as the following relationship in NaHCO3 solution: C(Na+)+C(H+)=C(HCO3-)+C(OH-)+2C(CO32-).

2. Conservation of materials: In the electrolyte solution, due to the hydrolysis of some ions, the types of ions increase, but some key atoms are always conserved, such as S2- and Hs- in the solution can be hydrolyzed, so the S element exists in three forms: S2-, Hs-, and H2S, and there is the following conservation relationship between them: C(K+)=2C(S2-)+2C(Hs-)+2C(H2S)=

3. Conservation of protons: H+ and OH- ionized by water in any solution are always equal, that is, the ratio of H and O atoms in the solution is constant 2:1, so there is: C(H+) + C(Hs-) + 2C(H2S) = C(Oh-).

The total number of positive charges carried by the cation is equal to the total number of negative charges carried by the anion c(Fe3+)*3

c(k+)*1

c(so42-)*2

c(k+)c(k+)=

All positive charges in the solution = all negative charges Find all the positive and negative ions in the solution and write all the positive ions on the side of the equal sign.

Write all negative ions on the other side of the equal sign, and if the solution is neutral, you don't need to write hydrogen ions and hydroxide ions in the solution.

According to the above method, it is obtained that 2C(Mg2+)3C(Al3+)= C(Cl-) and the ion if it is 123......Price.

This ion concentration is also multiplied by the corresponding valence.

Your first question is a question that you should also know about the precipitation equilibrium constant of magnesium hydroxide and aluminum hydroxide ksp otherwise it will not be answered.

Because you've all written it wrong.

The conservation of protons is not the ionization of water h+=oh-, but the protons provided by the acid in the solution are equal to the protons accepted by the base, which is the same as the conservation of transferred electrons in the redox reaction.

The moment NaHC2O4 dissolves in water, both HC2O4- and H2O start giving H+ as acids, and these H+ are acquired by another HC2O4- and H2O (as bases).

For every proton that an acid loses, it is left with a conjugate base (HA=H++A-, A- is called the conjugate base of HA, and HA is called the conjugate acid of A-). Every time a base gets a proton, it becomes a conjugate acid. According to this correspondence, hc2o4- gives protons and leaves c2o42-, and h2o gives protons and oh- remains, so c2o42-+oh- is the total number of protons provided by the acid.

In the same way, H2C2O4+H3O+ (hydronium ion, i.e., H+) is the number of protons accepted by the base. According to the conservation of protons, there is C2O42-+OH-=H2C2O4+H+.

While NH4Cl is soluble in water, NH4+ and H2O give H+ as acids, and the conjugate bases are NH3 (which will continue to react with water to become ammonia monohydrate) and OH-. The base in the solution is only H2O, and the conjugate acid is H3O+, so the proton conservation is NH3 H2O+OH-=H+, which is the proton conservation of NH4Cl.

Originally, we also know that NH4Cl solution is acidic, H+>OH-. And what you wrote and what you checked, both are h+

The amount of ammonia chloride and sodium hydroxide is equal, and the chemical equation we write should be a 1:1 relationship to produce sodium chloride and ammonia. Because sodium chloride is a strong electrolyte, while ammonia is a weak electrolyte.

Therefore, the sodium ion is equal to the chloride ion and the solution is alkaline after the reaction, so the hydroxide ion concentration is greater than the hydrogen ion concentration. The amount of ammonia chloride and sodium hydroxide is equal, and the chemical equation we write should be a 1:1 relationship to produce sodium chloride and ammonia.

Because sodium chloride is a strong electrolyte, while ammonia is a weak electrolyte. Therefore, the sodium ion is equal to the chloride ion and the solution is alkaline after the reaction, so the hydroxide ion concentration is greater than the hydrogen ion concentration.

I don't understand what you're asking, friend, a reminder, option b sodium hydroxide and ammonium chloride will react to produce sodium chloride and ammonia monohydrate. You calculate according to that concentration, and the reaction occurs in a ratio of exactly 1:1, and the chemical equation:

NaOH+NH4Cl=NaCl+, so it should be, the solution is alkaline after a one-to-one reaction (with the alkalinity of ammonia monohydrate). Now write the hydrolysis equation: I won't write sodium chloride, ammonium ion + hydroxide;

H2O = hydroxide + hydrogen ions.

In the above 2 formulas, you find that hydroxide ions are the most. So how do ammonium ions and hydrogen ions compare? It depends on the degree of ionization of ammonia monohydrate and water, ammonia monohydrate is higher than water, think about it, if there are really so many hydroxides and hydrogen ions in the water, then you can still drink water happily?

The degree of ionization of water is very small. I think so.

First of all, we must understand the reaction process, and secondly, we must understand how many substances are involved in the reaction, in this problem, the total reaction is NH4Cl + NAOH=NACl + NH4OH, the reaction is carried out in an alkaline solution, the reaction is a displacement reaction, so the solution is still alkaline OH H, the charge is conserved NA+H+NH4=OH + CL and because NA=Cl the result is out.

1.The aqueous solution of ammonia monohydrate is alkaline because ionization is greater than hydrolysis.

2.Sodium hydroxide is a strong base that is completely ionized, oh, the ionization of water in an aqueous solution is a small part, and the hydrogen and oxygen supply that comes out of the sodium hydroxide store will inhibit the ionization of water.

3.First of all, in the aqueous solution, the ionization of water is almost negligible, ammonium ions and hydroxide ions are produced in the ammonia monohydrate store, and the hydroxide ions will further inhibit the ionization of water, while in ammonia monohydrate, the hydrolysis of ammonium ions only accounts for a small part.

I haven't been to school in years,? Forgot about those topics? It's kind of funny in retrospect. Do you think so?

Problem 1: Digitize the specific concentration C. Let 1mol l be c(Na2SO4) = 1mol L

Then take 1L of the Na2SO4 solution, which contains 2mol of Na+ and 1mol of SO42-

Ion concentration in solution C(Na+) = 2mol L C(SO42-) = 1mol L

In essence, the reason why the number ratio is 1:2 is precisely to satisfy the conservation of charge. While the sodium ion has one positive charge, the sulfuric acid base group has two negative charges, and the two sodium ions must be used to satisfy the charge conservation.

So we get the formula C(Na+)=2C(SO42-)=2C(Na2SO4).

Problem two: Conservation of charge, this is a mixed solution. There is a repeat in the sulfate concentration. It can only be calculated according to the conservation of charge.

So each Al ion has a positive charge of three units, and each potassium ion has a positive charge of one unit.

Each sulfate carries two units of negative charge according to the conservation of charge necessarily 3C(Al3+)+C(K+)=2C(SO42-).

I feel like you're talking a bit too much and a bit of a mess...

How to say it. The solution is neutral, that is, the algebraic sum of the total charges of the anion and cation is 0, so it depends on the amount of charge of an ion band and the positive and negative.

For example, 1 Na+ has one positive charge, and 1 SO42- has two negative charges, so the number of SO42- should be multiplied by 2