Sodium acetate is made into ice, and the solution is cooled to how many degrees, must it be distille

Point water into ice. Preparation and operation: Put 60 grams of sodium acetate crystals (NaAC·3H2O) in a 250 ml beaker and inject 40 ml of distilled water, then heat on a water bath until the crystals are all dissolved, continue for a few minutes, take out the beaker containing the solution, and let it cool to room temperature.

Use a glass rod to reach into the solution and gently rub the wall of the cup or stir the solution or put a sodium acetate crystal into the solution as a "seed crystal", and suddenly needle-like crystals will be precipitated in the solution, and quickly spread to the bottom of the entire beaker, as if forming an "ice cube".

Note: Do not shake or stick to dust during the cooling process! Sodium acetate**!

Principle: This is an experiment on the instability of supersaturated solutions. The hot-saturated solution of sodium acetate is cooled undisturbed, and crystallization tends not to occur.

This solution is called a supersaturated solution and is a metastable system (unstable system, but still exists). When this solution is stirred or the "seed crystals" of solute are added, crystals of excess solute can be precipitated.

P.S. The same experiment can be carried out with sodium nitrate and sodium sulfate crystals (NaSO4·10H2O). Directly with sodium thiosulfate (commonly known as hypo:

Na2S2O3·5H2O) was carefully heated and dissolved into a supersaturated solution by using its crystal water, and the experimental phenomenon was more obvious.

It can be replaced by distilled water, heat the water to 60-80 degrees Celsius, add sodium acetate until it cannot be dissolved, and then cool to room temperature or below, if the crystals are precipitated during the cooling process, it can be reheated and then cooled, and the sodium acetate after the experiment can be reused.

Glacial acetic acid distillation temperature: 16 degrees Celsius. In general, the boiling point of the mixture is lower than the boiling point of any component in the mixture, and its melting point is 16

6, boiling point 1179, what temperature is suitable is related to the amount of other components mixed in it and its melting and boiling point, if it is water, it should be no problem at 100, but for these substances with a slightly higher boiling point, it is recommended to use vacuum distillation when **.

Acetic acid dimer.

The crystal structure of acetic acid shows that the molecules are bound into dimers (also known as dijunctions) by hydrogen bonds, and dimers are also present in the vapor state of 120. Dimers have high stability, and have been proven by freezing point reduction molecular weight determination and X-ray diffraction to prove that carboxylic acids with small molecular weights such as formic acid, acetic acid, and even gaseous states exist in the form of dimers in solid and liquid states. When acetic acid is dissolved in water, the hydrogen bonds between the dimers will be broken very quickly.

Other carboxylic acids have a similar dimerization phenomenon.

The above content reference: Encyclopedia - acetic acid.

toGlacial acetic acidFor solvents, withPerchloric acidWhen titrating the base of the standard solution, add the method between the two:

Glacial acetic acid of perchloric acid.

When the solution is used as a titrant, the perchloric acid in it must be close to pure, but the general mass fraction of perchloric acid used can only reach about 70%, so acetic anhydride should be added to change the water in it into acetic acid.

When titrating very weak bases with perchloric acid, the use of non-aqueous solvents (acetic acid acetic anhydride) can enhance the strength of the weak bases, increase the transition at the end of the titration, and increase the accuracy of the analysis.

Principle. The titration process requires a quantitative reaction, which must be complete and fast, i.e., the equilibrium constant and the rate constant should be large. Moreover, the reaction must not have by-products that interfere with the measurement, and side reactions are not allowed.

In the titration of the two solutions, the solution of known concentration is contained in the burette and the solution of unknown concentration is contained in the Erlenmeyer flask below. A solution of known concentration is usually referred to as a standard solution, and its concentration is measured by titration with a solid reference reagent that is not easily perishable.

There is nothing to say about the crystallization experiment of sodium acetate supersaturated solution, as long as sodium acetate solid is put into the sodium acetate supersaturated solution, or the solution is stirred with a metal rod, the saturated solution can be crystallized, that is, it becomes ice-like crystals. Then the key is the production of sodium acetate supersaturated solution.

It's actually pretty simple. At a higher temperature, prepare a saturated solution of sodium acetate, and then let the temperature of the solution slowly decrease, and a saturated solution of sodium acetate will be obtained.

For example, heat the water to 60 degrees, gradually put the sodium acetate into it, stir thoroughly, when the sodium acetate is no longer dissolved, the solution at this time is the saturated solution at this temperature. Be sure to remove the sodium acetate solids that are not dissolved in the solution, or add water at the same temperature to dissolve all the sodium acetate solids. When the temperature drops, a saturated solution of sodium acetate is obtained.

The greater the temperature drop, the better the experiment. But the chances of failure are also high. Be sure to handle it gently and do not allow the solution to be shaken.

If you want to perform sprinkling water into ice, it is best to sprinkle a small amount of sodium acetate on the table beforehand, and of course not let others know and find out. When the supersaturated solution is poured out slowly, there is a pile of ice on the table.

1 Take a 250ml beaker.

Infuse 50 ml of distilled water.

Add sodium acetate.

Dissolve it in water, stirring constantly, until it cannot be dissolved, with a thermometer.

The temperature of the measured solution is: , and the temperature of distilled water is, so the dissolution of sodium acetate is exothermic. (According to the actual operation, we use crystalline sodium acetate ch3coona·3H2O about 19 grams.)

2 Add another double amount of sodium acetate to the beaker, that is, 19 grams, and then put it on the electric stove to heat it completely to form a supersaturated solution. 3 Clean the sodium acetate on the inner wall of the beaker with a washing flask, pay attention to wash it with as little distilled water as possible, and then put it at room temperature to cool it slowly. 4. In the cooled supersaturated sodium acetate solution, gently touch the surface of the solution with your fingers, and the solution will gradually "freeze" in an instant, and the fingertips of the touch will feel slightly hot, and the "frozen" sodium acetate crystals will release heat, touch the beaker outside the wall, feel hot, and measure the surface temperature of the "frozen" sodium acetate with an infrared thermometer

41℃。Note: We conducted this test twice, the first time we touched the surface of the solution with our fingers, the solution did not react, and then the fingers dipped a little solid sodium acetate to touch the solution, and the solution immediately "froze" in an instant; In the second test, in order to see carefully, I got closer to the supersaturated solution, and blew lightly, only to see that the solution was "frozen" in an instant.

The children exclaimed: the supersaturated sodium acetate solution is so fragile?! It's a pity that the first test didn't expect to shoot **, and the second time was not open **, the solution was "frozen", although there was a certain regret, but we were very excited to see the results of the experiment.

Acetic acid. Water = hydrogen ion + acetate ion.

Also according to the chemical equilibrium constant.

The concentration of water remains unchanged after adding water, and the concentration of other ions decreases, so the chemical equilibrium constant decreases and promotes ionization, but because ionization can only be close to the original concentration of each substance, the concentration of each substance decreases, so C

Hello, I think a=b=c

Because no matter how the acetic acid is ionized, the amount of acetate ion + hydrogen ion in the solution is the same, so the concentration of the sum of the two in the solution is also the same, so a=b=c

There are also questions on the Internet that say that the answers are equal.

From A to B, C, the concentration of acetic acid is getting smaller and smaller, and the less acetic acid is contained in the same volume of solution, the less sodium hydroxide is consumed.

The degree of ionization of acetic acid should not be considered in this question, because sodium hydroxide reacts completely with any acid, regardless of the strength of the acid.

A. The conductivity of the solution is related to the ion concentration, the larger the ion concentration, the stronger the conductivity, and the greater the H+ concentration, the smaller the pH value, so the order of the pH of the three-point solution A, B, and C is C>A>B, so A is wrong;

B. The more dilute the solution, the greater the degree of ionization, so the ionization degree of acetic acid at A, B, and C is AC, and the test paper cannot be wetted by pH test paper, and the wetting will reduce the concentration of acetic acid, so C is wrong;

D's answer is incomplete, so it is impossible to judge whether it is correct or not.

Strong, learned. It's not good when I go to school in physics and chemistry!