The third unbelievable chemistry question for junior high school 10

Let me say a few words.

This statement is not true, because it is the reactants that participate in the reaction that are equal to the mass of the product.

The reactants include two aspects:1Participating in the reaction ("participating in the reaction" means that the molecule has a chemical change, so the molecule is consumed and does not exist) 2

Those that do not participate in the reaction ("not participating in the reaction" means that the molecule does not undergo chemical changes, i.e., the secondary molecule still exists).

Both 10g and 7g are reactants, but 3 of those 10g are not involved in the reaction and the remaining 7g are involved in the reaction.

In the equation of chemical reactions, the equals sign is the reactant in front of the equals sign, and the product behind is the product.

I'm not an expert, but I'm just learning right now, hehe, I hope mine is useful to you, the sum of the masses of the substances participating in the chemical reaction is equal to the sum of the masses of the substances produced after the reaction, this is the law of conservation of mass, you know, 7g, although there are 10g, but only 7g participates in the reaction, and the reactants are the ones who participate in the reaction, and they participate, you know.

The reactants are sometimes incompletely reactive, so there is a surplus after the reaction, and their mass is still equal, I think 10g is the reactant.

The sum of the masses of the reactants before and after the chemical reaction is equal to the sum of the masses of the products produced, and the reactants referred to here must be the mass of the substances that actually participate in the reaction.

A substance of 7g should be a reactant. According to the law of conservation of mass.

The substances that participate in the reaction and have a reaction are the reactants.

There is a very classic problem to add 50g of a metal mixture of mg, fe and zn to a sufficient amount of dilute sulfuric acid, and completely react to generate 242g of metal salt, and find the quality of hydrogen released. Because it is a sufficient amount of dilute sulfuric acid to completely react, the mass of the metal is all within 242g, and 242-50=192g is directly used to obtain the quality of sulfate combined with the metal. And then with the ratio of sulfate to hydrogen, 96 grams of sulfate are reacted to get 2 grams of hydrogen, and here 192 grams of sulfate are reacted, which is 4 grams of hydrogen.

Note that when the mass is known, it is independent of pressure.

So 32 grams of SO2 contains the number of molecules = 32 64 =

22 grams of CO2 contains the number of molecules = 22 44 = equal. Choose C

As many as possible, the number of molecules is related to the amount of matter, and the two are the same.

C should be chosen. The amount of the two substances should be equal at this time, both are.

The amount of c matter is the same, so there are the same amounts.

The number of molecules is related to the amount of matter, and has nothing to do with others, and the quantity of matter is only related to mass, and the bridge between the two is molar mass, so don't be confused by the interference information of the topic, the molar mass of sulfur dioxide is 64, and the molar mass of carbon dioxide is 44, so the number of molecules is all, which has nothing to do with pressure, temperature, etc.

1.Because the nails are submerged in water, there is no oxygen, but they will rust in small amounts. 2.

Obviously, B is the most prone to rust, so the amount of oxygen absorbed increases, C has a little rust, and D has no rust at all. A reacts with hydrochloric acid to release hydrogen, so the mass is reduced. b>c>d>a。

If there is no doubt,

Tap water also contains a small amount of chloric acid and oxygen, which will also make iron nails rust b rust the most, so the mass is the most, c is slightly rusty, the quality is slightly increased, d, the quality is unchanged, a iron is dissolved, the mass is minimal, if you have any questions, please ask. If there are no problems, please give a 5 star. Thank you.