Questions about chemistry are highly advanced.

In pure and dry air: at room temperature, it is very stable; When heated, copper forms black oxide, which is left in moist air containing CO2 for a long time: patina Cu(OH)2 CuCO3 is formed on the surface of copper; Silver and gold do not react.

Copper can react with sulfur; Silver reacts easily with sulfur and hydrogen sulfide; Gold does not react directly with sulfur. Prepare a dilute solution containing baking soda and table salt in an aluminum container, and when the blackened silverware is in contact with the aluminum container, Ag2S can be dissolved, and the blackened silverware becomes brighter.

Copper group elements can react with halogens: copper can react at room temperature; Silver reacts very slowly at room temperature; Gold reacts with dry halogens only when heated.

In the presence of air, copper can slowly dissolve in dilute acids; Copper is soluble in nitric acid or hot concentrated sulfuric acid Cu, Ag, Au soluble in oxygen-containing alkaline cyanide:

Cu is soluble in oxygenated ammonia:

Take a small amount of solid in a test tube, heat it with an alcohol lamp, and use a small beaker coated with clarified lime water in the test tube mask, if the small beaker turns white after a period of time, it proves that there is NAHC3, if there is no obvious phenomenon, then there is none.

Equation (principle):

2nahco3=△=na2co3+h2o+co2↑co2+ca（oh）2==caco3↓+h2o

It can be quantitatively assayed and titrated with hydrochloric acid. Let's assume that there is no NaHCO3 to calculate the volume of the required hydrochloric acid standard solution, and then see if the actual results are consistent with the theoretical calculations!

Heating, NaHCO3 is heated and decomposed into Na2CO3, CO2, H20, so just see if there is any gas generated.

When heated to a white solid, the presence of CO2 indicates the presence of NaHCO3

Can be heated There is gas generation (can make the clarified lime water turbid) - there is NaHCO3

If the tube connected to A is inserted into the liquid level, B is on the liquid surface.

1) open, close, 2) close, open, 3) the role of the reagent bottle to remove CO2 in the air, the role of the reagent bottle verifies that carbon dioxide is the final product of human metabolism.

The inhaled gas is first filtered through the reagent bottle. If there is CO2 in the air, the filtrate will absorb the CO2 in it, so that there is no CO2 in the air entering the body, so as to ensure that the CO2 measured in the reagent bottle does not come from the air.

The reagent bottle detects carbon dioxide and emits the possibility of coming from the air, which can only be considered as the final product of human metabolism.

Propylene (CH3-CH=CH2), which occurs under the condition of light, is a substitution reaction, and the substitution reaction can only be the substitution of hydrogen on the alkyl group by chlorine atoms, that is, the hydrogen on "CH3-", not the hydrogen on "CH=CH2". If you substitute one hydrogen, you can only get one product, because those three hydrogen allegories, substituting two hydrogens, can only get one product, and substituting three hydrogens, you still get one product. So up to three kinds of organic matter with different boiling points can be obtained.

They were: CHCL-CH=CH2, CHCL2-CH=CH2, and CCL3-CH=CH2, respectively.

It should be 3-chloropropylene, 3,3-dichloropropene, 3,3,3-trichloropropene.

The methyl group on propylene is replaced by a chlorine atom and can have 3 substitution products, namely monochlorosubstitution, dichlorosubstitution, and trichlorosubstitution.

Therefore, up to three kinds of organic matter with different boiling points can be obtained (organic matter with similar structure, the higher the molecular weight, the higher the melting boiling point, because the larger the molecular weight, the greater the intermolecular force).

d Possibly.

There have been many misconceptions or misconceptions about hydrogen energy, thinking that water can provide hydrogen energy. This question sets it as a secondary energy source, which is relatively accurate. Since it is a secondary energy source, it must require other energy inputs to split water to produce hydrogen.

Cheap energy comes from the world, not necessarily from special chemicals, but also from natural water, wind, tides, the sun, and nuclear energy. As for which one is cheaper, it all depends on the development and progress of technology.

Whether the high temperatures generated by solar energy can cheaply decompose water into hydrogen also depends on the progress and development of technology.

b da water does not decompose it is impossible to have hydrogen.

cWater splitting is a process of absorbing energy and can never release heat.

The equation of trilogy in atoms: number of nuclear charges = number of protons = number of electrons outside the nucleus and number of atomic numbers.

Number of protons + number of neutrons == relative molecular mass.

An atom is made up of a nucleus and electrons outside the nucleus.

The nucleus is composed of protons and neutrons (not divided into two layers) each proton has a unit positive charge, and the number of protons is called the number of nuclear charges, so the number of nuclear charges = the number of protons in the nucleus, We often say that the "nuclear charge number" of the oxygen atom is 8, that is, the proton number of the oxygen atom is 8.

We can also judge the number of protons of an element based on its atomic number, for example, the atomic number of oxygen is 8, the number of protons of oxygen is 8, and the number of electrons outside the nucleus of oxygen is 8.

This is because each electron has a negative charge of one unit, and the whole atom is invisible, i.e., electrically neutral, so the number of nuclear charges must be equal to the number of electrons outside the nucleus.

Atomic number = number of nuclear charges = number of protons = number of electrons outside the nucleus.

Mass number = number of protons + number of neutrons.

Atom x: number of nuclear charges z = atomic number = number of protons in the nucleus = number of electrons outside the nucleus.

Cation xn+: nuclear charge number z = atomic number = number of protons in the nucleus = number of electrons outside the nucleus n anion xn-: number of nuclear charge z = atomic number = number of protons in the nucleus = number of electrons outside the nucleus n mass number a = number of protons z + number of neutrons n

What is the number of molecules of an oxygen molecule!! Isn't that all the numbers clear?

In this kind of question, remember that the number of molecules in 1mol of molecules is (na=). So calculate how many mol (the amount of matter) there is and multiply it by na).

2g of hydrogen has 1mol, so the number of molecules is one.

The number of molecules of 2molCl2 is 2*.

The amount of 16go2 substance is. So the number of molecules is one.