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The position of the mercury ball is the temperature at which the steam is separated from the system, and it is more accurate to be the same as the boiling point of the substance to be distilled!

At this time, the temperature of the steam is slightly lower than the temperature of the liquid below, and it will not be equal!

If it is an alcohol lamp, adjust the distance of the flame from the bottom of the bottle to adjust the temperature.

When potassium chloride and manganese dioxide are separated, they should be dissolved first, manganese dioxide is not allowed to be dissolved in water, and potassium chloride is soluble in water.

After filtering, the potassium chloride will be removed, and a small amount of potassium chloride will stick to the solid surface of manganese dioxide, so there is washing, and it can be removed relatively cleanly.

1) Because to ensure that the distilled liquid is the target liquid, the temperature must be placed at the branch nozzle to control the temperature of the target purified product.

2) Equally, when separating two liquid substances with different boiling points, the temperature of the purified product must reach the target temperature, and the liquid will only vaporize into a gaseous state before it can be condensed.

3) The temperature of the target and other impurities is measured when the mercury ball is placed in the liquid, and the target purified matter should be measured when separating.

4) When heating with an alcohol lamp, when the eye-level thermometer is heated to the target temperature, the alcohol lamp is shaken back and forth to keep the temperature within the target temperature range.

1. It is placed at the branch pipe to measure the temperature of the fraction, which can reflect the content of the distilled fraction. The temperature of the liquid is not the same as the temperature of the steam at the branch mouth, so the thermometer should not be placed in the liquid. The amount and temperature of steam generation can be controlled by heating.

2.Potassium chloride is soluble in water, and manganese dioxide is insoluble in water. By washing with water, potassium chloride can be washed into the water, so that pure manganese dioxide is obtained. There is potassium chloride in the water, and after evaporation, it gives pure potassium chloride.

Because it is necessary to control the outlet temperature at the boiling point, it is not equal, and the heating is controllable.

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-)

Copper reacts with nitric acid to produce Cu(NO3)2 and nitrogen oxides. If copper is known to be amol, then the nitrate in Cu(NO3)2 is 2amol. Nitric acid is a total of b mol, and after removing the copper nitrate, all the rest is reduced (because it happens to be completely reacted), that is, (b-2a)mol

1.There is a white precipitate, and the reaction equation: ag+cl-=agcl 2There is a white precipitate, and the reaction equation is: Ba2+ +SO42- = BaSO4. If soluble in acid, it is barium carbonate, and insoluble in acid is barium sulfate.

3.Barium nitrate is added first, a white precipitate is generated, after the precipitation is filtered, HCl is added to the precipitate, and the dissolved is barium carbonate, and the reaction equation is: BAC3+2H+=BA2+ +CO2+H2O; Insoluble is barium sulfate; This proves the existence of CO32- and SO42-.

Finally, silver nitrate was added to the filtrate, and a white precipitate was generated, and the reaction equation was: AG+CL-=AGCL

It's called "electrode reaction".

Negative electrode: Cu-2E- = Cu2+

Positive electrode: 2ag+ +2e- = 2ag

Positive reaction: 2ag+ +2e- == 2ag

Negative electrode reaction: Cu—2E- ==Cu2+

<> I sent the front part of the first to return to the leakage of the manuscript.

<> satisfied with the head of the file, please take the old and prepare for the stupid destruction (