Sophomore chemistry, ask the teacher for help, a chemistry problem in the sophomore year, I hope the

The problem of pH = 10 heating evaporated salt is more complicated, and there are several situations.

The third distinction between hydrolysis and ionization is to see whether the water molecules of the reactive species are dismantled into H+ and OH-, which is hydrolysis, and ionization is generated by water and hydrogen ions.

1，ph=10

2. To see the composition of the salt solution, if the acid of the original solution is a volatile acid, then evaporation will produce gas, such as CuCl2 to obtain copper hydroxide If the metasolute is easy to be oxidized, the oxidation product is obtained, and if the original solute is easy to decompose, the decomposition product such as sodium bicarbonate solution becomes sodium carbonate.

3 The method is very simple, the hydrolysis reactant has water, and the ion symbol before and after hydrolysis is the same, and the ionization is opposite.

pH=10, weak alkaline cation and easy hydrolysis to evaporate to form the corresponding precipitation; Salt that is easy to decompose at high temperatures will not get the original substance by heating and evaporation; Strong acids and alkali salts can precipitate protosolutes.

The hydrolysis equation must have water, and the ionization equation is that the electrolyte or solution or water is broken down into ionic form.

I don't know how to ask questions.

1、ph=–lg10-10 =10

2. It can be judged if there is crystal precipitation.

3. Ionization is the process of ionizing hydrogen ions or hydroxide ions, and hydrolysis is the alkaline combination of weak acid ions in salt solution combined with water, or weak alkali ions.

1、ph=-log（ch+）=-log（

2. Generally, it can be divided into three categories:

One is strong acid and alkali salts such as sodium chloride and potassium sulfate solution, because there is no change in the heating process, so the solid product obtained by evaporation is still the original salt;

The second type is a strong alkali weak acid or weak alkali strong acid or weak acid and weak alkali salt solution, although there is hydrolysis of salts in the heating process, but the hydrolysis results do not generate volatile and insoluble water-insoluble products at the same time, such as sodium sulfide, potassium phosphate, etc., and the solid products are still the original salt after evaporation and burning. However, acid salts generally generate positive salts, solid nitrates need to be decomposed, and low-cost salts need to be generated into ** salts.

The third type is a soluble salt composed of weak alkali and volatile acid, which is hydrolyzed in the solution to form insoluble weak alkali and volatile acid, with heating and evaporation, the hydrolysis in the hydrolysis solution continues to increase and completely, generating insoluble alkali and volatile acid, as a result, acid and water vapor volatilize first, leaving behind insoluble alkali, after burning, insoluble alkali and then decompose, to obtain metal oxides, such as aluminum sulfide, iron bromide, aluminum chloride, iron oxide, etc.

3. The hydrolysis equation must be that the ions of salt (acid or metal cation and ammonium) react with water, and the ionization equation generally does not have water (except for the water ionization equation), and hydrolysis must be a reversible reaction, while ionization is not necessarily.

1 ph=10

2. The solid products after evaporation of salt solution can generally be divided into three categories: one is strong acid and alkali salts such as sodium chloride and potassium sulfate solution, because there is no change in the heating process, so the solid products obtained by evaporation are still raw salts; The other type is a strong alkali weak acid or weak alkali strong acid or weak acid and weak alkali salt solution, although there is hydrolysis of salts in the heating process, but the hydrolysis results do not generate volatile and insoluble water-insoluble products at the same time, such as sodium sulfide, potassium phosphate, etc., and the solid products are still the original salt after evaporation and burning. However, acid salts generally generate positive salts, solid nitrates need to be decomposed, and low-cost salts need to be generated into ** salts. The third type is a soluble salt composed of weak alkali and volatile acid, which is hydrolyzed in the solution to form insoluble weak alkali and volatile acid, with heating and evaporation, the hydrolysis in the hydrolysis solution continues to increase and completely, generating insoluble alkali and volatile acid, as a result, acid and water vapor volatilize first, leaving behind insoluble alkali, after burning, insoluble alkali and then decompose, to obtain metal oxides, such as aluminum sulfide, iron bromide, aluminum chloride, iron oxide, etc.

3. The hydrolysis equation must be that the ions of salt (acid or metal cation and ammonium) react with water, and the ionization equation generally does not have water (except for the water ionization equation).

pH=10 2 What impurities are there in the solution The ionization equation condition must be ionized.

Because c(hcn)>c(cn-) and c(hcn)+c(cn-)=, c(hcn) >

And the concentration of na is exactly.

So c(hcn) > c(na+).

c(hcn)+c(h+）_c(na+)cn-+h20=hcn+oh-

So HCN is exactly 1 2 of the oh- produced by its hydrolysis than cn, but there is also oh- of water ionization, so.

c(hcn)-c(cn-)]/2 _

At room temperature, the HCN solution is mixed with the same volume of the Nacn solution, and the solution is C(HCN) and C(CN).Then the pH 7 in the mixed solution [Originally, the concentration of the two particles is equal, and the c(hcn) c(cn) in the solution indicates that the ionization of HCN in the solution is less than the hydrolysis of CN, and the hydrolysis of CN produces OH, so the solution is alkaline. 】.

c(hcn) c(cn) cn is completely hydrolyzed into hcn, then c(hcn) is, because cn cannot be completely hydrolyzed to form hcn, it should be less than. C(OH [Because CN cannot be completely hydrolyzed, HCN and OH are generated.]cn +h2o==hcn+oh so c(oh should be less than more should be less than; Fill in or or

c(hcn)> c(cn-)

The material conservation formula is: 2C(Na+)= C(HCN) +C(CN-)C(HCN)> C(CN-).

Introducing c(cn-) while the charge conservation formula is.

c(cn-) c(oh-)=c(na+)+c(h+) because c(cn-) so c(oh-)>c(h+).

The solution is alkaline.

pH(greater than) 7,c(hcn)+c(cn-) =,【c(hcn)-c(cn-)】 2, less than) c(oh-) because from the above two conserved formulas, obtained.

c(hcn)-c(cn-)】/2 +c(h+)=c(oh-)

A is the anode. Because sodium hydroxide is formed in B, that is, the hydroxide ions left over from the reduction reaction of hydrogen ions in B are combined with sodium ions, so A is the anode.

2Cl (ion) - 2E---Cl2

n material is zinc. Because B connected to N is the cathode, N is the negative electrode of the galvanic battery, that is, the oxidation reaction occurs, so it is zinc that loses electrons as the material.

What's ......Don't be surprised if you're wrong.

a is the anode electrode reflected as: two chloride ions lose two electrons to get chlorine gas 2cl-2e===cl2

N is the cause of zinc: because B is red near B, OH- ions are produced near B, according to the reaction of electrolytic sodium chloride aqueous solution, B is the cathode, so A is the anode, N is the negative electrode, and Zn is the negative electrode in the reaction Zn+CuSO4=Cu+ZNSO4, so N is zinc. Thank you!

A is the anode, and the electrode reaction that takes place is the electrolysis of the anode of NaCl 2 chloride ions lose 2 electrons to produce chlorine gas.

The n electrode is copper, because you have to produce chlorine gas on the C rod, the cathode generates Naoh, and the anode must be an inert electrode (if the anode becomes iron, the iron will lose electrons), so M must be the negative electrode of the galvanic cell, and N is the positive electrode of the galvanic cell; In the electrolytic cell, m is the cathode, and n is the anode, so n is zinc.

Mark a mark on the graph by yourself, this kind of electrochemistry comprehensive question is often tested.

and acetic acid.

mg+2h+=mg2+ +h2↑

a24/a=2/

A = requires A, complete consumption of acid.

6.Slowly translate B upwards until B and C are at the same level as the liquid, as the pressure is to be kept the same.

1.Pick B. mg+2h+=mg2+ +h2↑

2 1 Assuming that it is the standard condition, the volume of H2 is v=n*vm=, which is actually slightly larger than this volume, and it is most suitable to choose a 200ml measuring cylinder.

l molvml = l, gas molar volume vm = v n = l mol

Analysis: This topic is a simple experimental device to study the reaction of monobasic acids with different acidity at the same temperature and pressure, the same concentration and the same volume of acidity react with a sufficient amount of magnesium belt, the volume of hydrogen gas is the same and the reaction rate is different, and the molar volume of gas under laboratory conditions is determined at the same time.

mg — 2h+

24 g 2 mol

a g mol

a During the reaction, the time required for the reaction to complete should be recorded to compare the reaction rate. B can be slowly moved up to the same level as the liquid in B and C. When the air tightness of the device is tested, it is slightly heated A, and the change of liquid in the right catheter in B is observed; The gas produced in this experiment is about 112 ml, so choose a 200 ml graduated cylinder.

Answer: Acid burette or ml pipette.

The time at the beginning and end of the reaction.

Slowly translate B upwards until B is on the same level as the liquid in C.

1) Keep the palms of both hands close to the outer wall of the Erlenmeyer flask for a while, if you observe a section of water column rising to the liquid level in the right catheter in the jar, it means that the device does not leak.

2)b3) l·mol-1

4) The reaction rate is different when the concentration of the acid is the same, which prevents the formation of galvanic cells and interferes with the observation of experimental phenomena.

I hope to add more points!

SO2, SO3, Cl2, and HCl are acidic gases that can be removed with alkaline solution (NaOH).

CO oxidizes to form CO2, which is removed by NaOH solution.

After the oxidation of NO2, NO2 is generated, which is passed into the NAOH solution, and because NO2 reacts with the water in the solution to form HNO3, it reacts with NAOH, so NO2 and NO2 are removed by this method

O2 is removed with potassium permanganate solution.

2.Anhydrous copper sulfate is blue when exposed to water, Cuo (black), long-stored phenol (pink), solid O3 (purple-black), bromine water (orange), AGI (yellow), Cu2 (OH) 2CO3 (green) ......

3.Potassium permanganate is a purple-black flake crystal at room temperature, which is easy to decompose when seen in light.

Potassium permanganate is prepared from manganese dioxide as raw material, used as disinfectant and bleach in industry, and in the laboratory, potassium permanganate is used for substance identification because of its strong oxidation and bright color, and acidic potassium permanganate is an important reagent for redox titration.

Potassium permanganate is more oxidizing in an acidic environment, and can oxidize chlorine, bromine, iodine, sulfur and sulfur dioxide. The reduction product of potassium permanganate in a neutral solution is generally manganese dioxide. Potassium permanganate oxidation product in alkaline environment is dark green potassium manganate.

4.Similarities: Uh...., all have s, o, all compounds....

Differences: After adding BA(OH)2 to sulfuric acid and sulfurous acid solution, precipitation is produced, but after hydrochloric acid is added respectively, the precipitate (Baso4) in sulfuric acid is insoluble, and the precipitate (Baso3) in sulfurous acid dissolves to form BaCl2, water, and SO2.

5.Magnesium, like aluminum, can react with oxygen in the air to form a dense oxide film, which can protect the magnesium inside, so it does not need to be sealed and stored. Highly reducing metals such as potassium, sodium, and calcium are preserved in kerosene.

In addition, the storage of reagents should be considered from the following aspects: whether it reacts with H2O, CO2, O2 in the air; whether it reacts with SiO2 in glass; whether it is easy to decompose when it sees light; Choose a jar or a jar according to the state of the reagent.

6.Reaction equation: mg 4hno3 ==mg(no3)2 2no2 2h20

3mg 8hno3==3mg(no3)2 2no↑ 4h20

Formula: Copper nitrate metal, no hydrogen is released in the reaction, concentrated nitrate is one or four brown, and dilute nitrate is three or eight no. over

I hope I can help you, and I wish you admission to the university of your dreams!

1 Do you need to design a set of instruments to eliminate or a single one?

2. Black carbon, yellowish sulfur.

3. Strong oxidation.

4 The difference between salt and acid You don't understand it at all?

5 Because air and magnesium react to form a dense oxide film that prevents further oxidation.

6 I won't write about it when it is reflected with dilute nitric acid, and it will also produce gas, not to mention confused, you haven't studied chemistry.

No oxidized to CO2 first, NO2 and then SO2 SO3 Cl2 No NO2 HC can be used to get out with NaOH. Reaction of alkaline solution and acidic gas. O2 can be removed with a solution of potassium permanganate.

2.Black potassium permanganate, yellowish sodium oxide, etc., too much.

3.Potassium permanganate has strong oxidizing properties and color rendering.

4 sulfite sulfate sulfate sulfurous acid sulfuric acid all contain s. Sulfite Sulfite S in sulfurous acid is 4 valent unstable, sulfate S in sulfuric acid is 6 plus very stable.

5.Magnesium reacts with oxygen, not with air. Sodium is kept in kerosene, k in paraffin, etc. Gold and silver are chemically stable, so you can just carry them on your hands.

6.When magnesium reacts with nitric acid, an oxide film is formed on the surface to prevent the reaction from occurring. Concentrated nitric acid is the same as dilute nitric acid.