Junior High School Chemistry Problems Urgent, Junior High School Chemistry Problems 。。。。。。

Assuming that the metal element in this metal oxide is also 2 valence, then the mixed oxide can be expressed as mo, and since it contains the element oxygen, the amount of the substance containing the element m is, the amount of the substance of the element oxygen is, and the amount of the substance of the element m is also.

So the relative atomic mass of the m element is.

It is known that one of the mixtures is MGO, and the relative atomic mass of MG is 24, which is greater than, so the metal element in the other oxide should be less than the equivalent relative atomic mass of 2 valence, and the only metal oxide that we have learned meets this requirement is the Al element, which is equivalent to 18 after becoming 2 valence, and the equivalent relative atomic mass of other elements is greater than that, so it is Al2O3

If the oxygen content in the MGO is 40% and the oxygen content in the mixture is 45%, then the other metal cannot be bivalent Because the oxygen content of MGO in the divalent metal oxide is the highest, and it is even more unlikely to be monovalent, because the maximum oxygen content in the monovalent metal oxide is Na2O, and it is less than 40% The only thing left is the trivalent metal The general formula of the trivalent metal oxide is X2O3 As long as the relative molecular mass of this metal element is less than two-thirds of the molecular mass of the metal element, the answer is AL.

In fact, to put it simply, as long as the chemical formula of metal oxide should be in the form of several metal atoms corresponding to one oxygen atom, and then calculate the oxygen content at this time, as long as it is greater than 45%.

This should be a gas collection cylinder, and the end from which it is introduced is related to the density of the gas.

When the density of the gas is smaller than the density of the air, such as hydrogen and ammonia, then it should be introduced from A, because the gas will float on the air, the air will be pressed down, and the air will flow out through B, which is called the downward air exhaust method.

When the density of the gas is greater than that of the air, such as carbon dioxide, then it should be introduced from the B terminal, and the gas will sink to the bottom, pushing the air upwards and the air flowing out of A. This is called the upward exhaust method.

The relative molecular mass of the air is 29, according to which the density of the gas can be judged whether the density of the gas is large or small.

The liquid inside is short in and long out, the air inside is lighter than the air in and long out, and the heavier air is long in and out.

The exhaust method collects gas: the gas with a density greater than the air density enters and exits from pipe A and pipe B: the gas with a density less than the air enters and exits pipe A from pipe B.

Drainage method to collect gas: the premise is that the gas is insoluble in water and flows from pipe A to pipe B.

Because air is a mixture, the relative molecular mass of air is about equal to 29, as long as the relative molecular mass is less than 29, the density is less than air, for example: the relative molecular mass of hydrogen is 2, less than 29, so it is a in and B out.

When the A end is entered, the gas is collected by the drainage method, the gas is light, and the pressure is applied above the liquid level to squeeze the water out.

The B-terminal entry is for the purpose of washing the gas and allowing the gas to be in full contact with the solution.

The B-end is through the water, like oxygen is through the B-side, usually through the B-side.

If the density of the incoming gas is less than that of air, it will be introduced from the A-terminus, and if it is heavier than the air, it will be introduced from the B-terminus.

The density of the gas is greater than that of air from the A terminal, and the density of the gas is less than that of air from the B terminal.

If it is used to collect gas from A, if it is used for washing gas from B.