Chemistry problems, urgent solutions, urgent solutions to chemical problems

1. You can use NaOH, but this thing is relatively high.

2. Hypochlorous acid does decompose under light, but the decomposition rate is not so fast. In general, the decomposition of hypochlorous acid mostly occurs after its bactericidal effect. Therefore, the effect of light on its sterilization effect is not so great, and it is usually the effect on the storage process of hypochlorous acid.

3. The solubility of Cl2 gas produced in the solution can be reduced with saturated salt water, so that more gas can be volatilized. As for chlorine, there must be a certain degree of dissolution in saturated brine, but with saturated saline, the solubility of chlorine will be significantly reduced.

4. During the dissolution process, it will absorb heat, so that the water vapor will condense into droplets.

5. In fact, most liquids are volatile, but the speed of volatilization is different. Volatility refers to those liquids that evaporate at a faster rate.

6. From the perspective of liquids, volatility is the difficulty of surface molecules to disperse into air or gas without bondage. The more intense the molecular movement, the smaller the binding effect, and the easier it is to volatilize.

7. This should be said according to different situations. If the purity of the species is not high and the impurities are not easy to remove, there can be less impurities left. In addition, under different preparation conditions, impurities can be removed at one time or step by step.

1.No. 2. Decomposition is slow.

3.In addition to HCL, chlorine is also dissolved in water, and the reaction between chlorine and water is reversible, and the chloride ions in saturated salt water shift the balance of chlorine and water reaction to the left, so that no new impurities will be produced.

4.It may be that the HCl molecule adsorbs multiple water molecules to form small droplets.

5.Volatility should include aspects such as whether the substance is volatile or not.

6.The concept of volatility is the only way for molecules to be volatile when molecules are in constant motion.

7.It is not necessarily undemanding, and there can be a little impurity.

1.I don't know, I don't think so.

2.The decomposition rate is slow in places with low light, such as indoors.

Dear landlord, what's the problem?

Why don't you give that question, dear? How embarrassing.

Assuming that the volume of gastric fluid in the human body is V, the excess HCL can be removed after taking N tablets of gastric stool, and since the density of gastric fluid is about 1g cm, the volume of gastric fluid is approximately equal to the mass of rock slag.

Under normal circumstances, the HCL content is about, and the average value is about.

Now that its content is found to be, the excess HCL is about.

The dosage is calculated as follows:

al(oh)3 + 3hcl = alcl3 + h2ov*

The solution gives n=(v*

This question lacks a key condition, the volume v of gastric juice, so it is strictly impossible to calculate the specific result.

After investigation, under normal conditions, the amount of gastric juice in the human stomach is about 10 100ml, and the average value is about 50ml

The daily gastric secretion of the human body is about 1500 2500ml, and the average value is about 2000ml.

n1 = 1 tablet.

If the second value is taken to calculate, then there is.

n2 = tablets. It seems appropriate to take the first value, given that the amount of gastric juice varies from person to person and that gastric juice will continue to be secreted.

It should be enough to take 1 2 tablets at a time.

Analysis: There are a total of 4 elements, some of which can react with dilute hydrochloric acid, indicating that one of the active metals is generated, forming a light green mixed solution, indicating that there is an iron element, and the resulting solution is a mixture, indicating that there is also a substance that reacts with dilute hydrochloric acid, but it is colorless.

Excess metal aluminum is added to C, filtered, and a mixed solution E is generated, and the solid D metal aluminum and ferrous chloride are replaced, but the solution is still a mixed solution, indicating that there are still those that do not react with Lu, and they are not K, Na, Ca, so it can only be mg

E contains AlCl3, and F is Fe, Al

After the full reaction of solid D, a colorless gas G is generated, and the black solid H indicates that there is C in D, and H is Cuo

Excess dilute sulfuric acid was added to the black solid H to generate blue solution II as CuSO4

The answer is: 1) Fe, Cu, C, Mg

2) Light green mixed solution, C is a mixed solution of ferrous chloride and magnesium chloride, and solid D is copper.

Mixed solution E is a mixed solution of aluminum chloride and magnesium chloride.

Solid f is iron.

The colorless gas g is carbon dioxide.

The black solid h is copper oxide.

Blue solution i is a copper sulphate solution.

Let's start with the gas g.

Human metabolites are colorless, gaseous, and burning, so it's definitely carbon dioxide, and it's gone.

Pushback d is a solid that is insoluble in dilute hydrochloric acid, and there must be carbon elements in it, and after burning, a black solid will be formed.

Note that the full combustion here actually indicates that all the carbon elements are burned out, and a large amount of oxygen enters d) the black solid H reacts with dilute hydrochloric acid to form a blue solution, so it must be copper ion pushback, copper elements do not react with dilute hydrochloric acid, oxidizable copper can react with dilute hydrochloric acid to form copper chloride and water, so it makes sense, so it is concluded that there must be copper and carbon elements in A, and react with dilute hydrochloric acid to form colorless gas b and flammable, suspected to be hydrogen, and the following is verified to form a light green solution after reacting with acid, which should be divalent ferrous ions So there must be iron in elemental A.

And it makes sense that iron does react with dilute hydrochloric acid to produce hydrogen.

However, it is not possible to determine whether magnesium and zinc are present in the alloy.

Therefore, the following addition of excess aluminum to the light green solution is to verify that it contains magnesium and zinc, and if it contains any of them, then solution c not only has ferrous ions, but also a strong base, and the excess aluminum will react with the strong base to form hydrogen.

However, ferrous hydroxide, which is a weak base, does not.

Since experiments show that no hydrogen is generated, it is inferred that there is no magnesium and zinc in C, so the alloy should only contain three elements: copper, carbon and iron.

Method 1 measures the density of two solutions, the denser is the aqueous solution, and the smaller is distilled water. Method 2 is distilled with two solutions, and the last residual is aqueous solution, and the other is distilled water.

Magnesium carbonate. It is easy to decompose into when calcined.

Magnesium oxide. and carbon dioxide.

In the end, all that is left is magnesium oxide, the element magnesium.

There is no change before and after the reaction, the total mass.

If the measurement is equal, the mass fraction of magnesium in the original mixture is equal to that of magnesium in pure magnesium oxide.